Sudan Academy of Sciences

Governmental University for Postgraduate Studies

I

Comparison between INAA and ICP-OES: Analysis of Sudanese

Medicinal PlantsA thesis submitted in partial fulfillment of requirements for the degree of

Master in nuclear sciences & technology

July 2014

ByElsadig Abdelmoniem Sheikhaldin

B.Sc. of Mathematics and Physics

University of Khartoum

Supervisor

Dr. Ammar M Ebrahim

Sudan Atomic Energy Commission

Sudan Academy of Sciences (SAS)

Governmental University for Postgraduate Studies

Atomic Energy Council

Comparison between INAA and ICP-OES: Analysis of Sudanese

Medicinal Plants

A thesis submitted in partial fulfillment of requirements for the degree of

Master in nuclear sciences & technology

By

Elsadig Abdelmoniem Sheikhaldin Mohammed

B.Sc. of Mathematics and Physics

University of Khartoum

Examination Committee

Title Name SignatureSupervisor Dr Ammar M Ebrahim s /

- L . . . . y . . . .

External examiner Dr Abubakr Mustafa Idriss, - • I

r ^ r * V ^ J

>•

July 2014

List of contents

Page

Dedication

Acknowledgements n

Abbreviations m

Abstract IV

Arabic Abstract ; Vj 1 i p *List of hgures 1 VI1

---------------- ....... ................ ...........—W

List of'TablesI1|

1 VIIii

j Chapter One: Introduction1

lij

i1. Introduction ; ilLI. Medicinal plants ■ ,i\

1.2. Historical roots of medicine in Sudan .ii1.2.1. Traditional Sudanese medicine

i

1.2.2. Overview of medicinal plants in Sudan \ n ! P

L

1.3. Importance of trace elements i— 1------------------------

1.2.1. Chromium ! 4IrI

1.2.2. Copper 14

1.2.3. Iron ! 5

1.2.4. Magnesium

1.2.5. Zinc\--------------------------1

! S1

1.2.6. Calcium 6l!L

1.2.7. Potassium | 6|i

1.2.8. Manganese 6l

1.2.9. CobaltJ

7' ' im ' ' —----1 1 " 1

1.2.10. Strontium 7

1.3. Role of trace elements in medicinal plants nl

i _ . . .

1.5. Instrumentation 8

I1.5.1 Instrumental Neutron Activation Analysis (INAA)

1.5.1.1. Basis principles

8! 9

1.5.1.2 INAA how does it work?

15.1.3. Neutrons sources

; | 0; .__

t ^j

1.5.2 The general equation of neutron activation !41.5.3 Types of standardization 16

1.5.3.1 The ko-comparator method1

17

1.5.3.2 Applications, Advantages and Limitations of NAA I i ni /— .—* i

1.5.4 Inductively Coupled Plasma-Atomic Emission Spectroscopy (1CP-AES)

Chapter Two: M aterial and M ethods

2 Material and Methods !1 ^ »

2.1 Sample collection ! 24. _____ 1

2.2 Sample drying and homogenizingr •

j 241j ____ _

2.3 1CP-OES measurement ' A 1III

2.3.1 Sample preparation 24

2.3.2 Sample analysis 26I

2.4 INAA measurements

2.4.1 Sample preparation

! Ni

jii

2.5.2 Sample irradiations and measurements 2 6

Chapter Three: Results and Discussion i_____1__

3. Results and Discussion 281

3.1. Quality control ........... f--------------------i A Q 1 O1f

3.2. Comparison of INAA and 1CP-OES results\ ----- ----------------- ’1 n

s ^

\» ...... .....■■ ■—---— • ■

3.3. Conclusions 38ii

Chapter Four: References !j1i

— --------------------------------.

4. References 39

(Dedication

To my beloved parents

To my aunt A watif

To my brothers and sisters

To my close friend Ahmed Hamed

To all o f them...1 dedicate this work

Elsadig

I

Acknowledgments

Foremost and ultimate thanks to Allah. My deepest and sincerely thank to my supervisor Dr.

Ammar M. Ebrahim for his guidance, understanding and patience throughout this study.

This work was done with the help of the staff at the Research Unit of Analytical BioGeo

Chemistry and the financial support of Helmholtz Center Munich - German Research Centre for

Environ- mental Health, Neuherberg-Germany. The practical work at the reactor is done with the

support and understanding of the staff of National ETiergy Center of Nuclear Science and

Technology-Morocco and the financial support award of the International Atomic Energy

Agency (IAEA). Thanks are also due to Dr. Saif Aldin M Babikir for a fruitful cooperation and

for his willingness to respond to my inquiries.

II

Abbreviations

f * - -

Abbreviation

ATP

Name

Adenosine triphosphate

CRM

DON A A|

Certified Reference Material

Delayed Gamma-rav Neutron Activation Analysis+ / w/ w'

Gil1!'

Glucose Tolerance Factor

! HPGE High Purity Germanium1i

. .............. . _____ _________L_ _ . . . . . . . . . . . . . . ... ____ _______________ . . . . . . . . . . .

: KT-Ol s

IN A A

Inductively Coupled Plasma-Optical Emission Spectroscopy

Instrumental Neutron Activation Analysis

PGNAA

: PMT*

Prompt Gamma-rav Neutron Activation Analysis

Photo Multiplier I’ube

SD Standard Deviation

SRM

WHO1

Standard Reference Material

World Health Oruanization

WT%1

Weight percent

r ^

Abstract

The aim of this study was to provide elemental concentrations in medicinal plants and mainly to

compare the two different determination methods (INAA and ICP-OES after wet digestion)

Elemental analysis of 14 Sudanese medicinal plants was carried out using INAA and ICP-OES

techniques. The selection of reported elements was done according to the intersection of

elements determined by both techniques. This intersecting element list contained Ca. K. Fe. Mn.

Mg, Sr, Zn, Cu, Co and Cr.

INAA correlated well with ICP-OES measurements of the same plants as long as concentrations2

were sufficiently above LoQ. Correlation coefficients (R ) in this case is close to 1. Generally.

INAA results tended to be higher compared to ICP-OES. The performance and possible sources

of errors of both techniques was discussed also with respect to measurements of certified

reference materials. INAA provided the advantage of having both, faster and non-destructive

sample preparation than ICP-OES. Therefore, INAA may be a technique of choice for Ca. K, Zn

and Mg elements specifically when samples are needed for further investigations. Regarding the

low concentrations e.g. for Cr, Ni or Cu, ICP-OES is the superior technique over INAA due to

the sufficiently low limits of determination and thus gaining more detectable results at low

concentrations.

I V

Jilajll AjjLLaU ( i l l i j -‘L nU l ClAjUill i Cj Ujc- ^ 0jJ>i3l jj^-saUxJl j J l ojiA >■ Og'i

4_ilc. !$,Li)j I *4 ) ( IC P - O E S ) ^ ! ^ ' L . j ^ b 4JjS-Jl aMJI Abbb* J ( IN A A ) ^ iy ~ ^ - -e b b

f ajiwillSll (jx i ^ 4»uAjLa]l 4j )lLd CLlgj. Amj uc' \\\ \j<A 1 j

OljUill Ljlilfr (j-iiil ICP-OES 4-kJJj fjSlb lAUk Ualfijl INAA 4-kujlJh? l&dc. J^x^ull

^ / f a

U*Jl j£\ JJ« ** * ! JaJjullijLj (Jjlaall ljUu (jl # jA-eaUxjI L-lic-V -lauu all <o 1.1. <JJ )ii JaLiijV , 3-aljtx 4<u3 Clul£ j

4_i3ljJaA J j j j l a ^jC> l^jlc- (Jj^a^Ldll 0jUull 4 jjlL dJl .lie- £-»Ja3 * u-ilc-V lk_£-lc'l J-i^' j J v—Ll

4 LdjiMJ'L!V b

JX ALbbll Abiill U jL u c I jL w b l]J U 4.1c. I b e ib liu Jl c i ib l ^ J e j A ^ ^ J b I C P - O E S J t IN A A A ijjia b jjx b

ja ba.b. bUliA - ‘'■~'r- 1 . ^ ** blljllj r* 3}.' ‘J ~1T 4l ; j ; ’1* -4l . ■ i —Li' J )l-» i

. ** it w+\\ \r„ q fl Vi'

41J INAA ( jic J j i b I C P - O E S u ' ^ <_>4ajJlj (JSbJl , _>-=>be J ib A ^ b b b il JySI jb b ^ 1 3 L b j b b e

Ab j 2SI j Aj’i j8%. l^xbbj J jSI J i l l lia> A_Joibbll jijill w""'1 4 ^ j b b

V

List of Figures

Paget.........

11Figure 1.1 Diagram illustrating the process of neutron capture by a target nucleus followed by the emission of gamma rays

Figure 1.2 Flow chart for a gamma-ray spectroscopy system 13|

21r

Figure 1.3 Schematic representation of a radial Inductively coupled plasma optical emission spectroscopy (ICP-OES)

Figure 1.4L

The excitation, relaxation and subsequent emission of light from electrons,

21

Figure 3.1 IN A A SRM ] 547 relative error % ! - ]

I Figure 3.2 ICP-OES ERM-CD 281 relative error %T

31J_____ . . . ,

Figure 3.3|

ICP-OES ERM-BB 150 relative error % N|

S i

[ j

Figure 3.4 Plant calcium contents measured by INAA and ICP-OES 35r

i

Figure 3.5 Plant potassium contents measured by INAA and ICP-OES j 3^

Figure 3.6J!

Plant zinc contents measured by INAA and ICP-OES 36 jj•

: Figure 3.7 Plant manganese contents measured by INAA and ICP-OES ! 37

Figure 3.81

• 1

Plant magnesium contents measured by INAA and ICP-OES j 37

Figure 3.9f1b . . .

Plant iron contents measured by INAA and ICP-OES 371

i1

Figure 3.10Jti

Plant cobalt contents measured by INAA and ICP-OES 38 ;j1i

Figure 3.11- ' ‘ ‘ 1 ---------------" -------------------- — — — ------------ - ---------------- - --- ----------------------- !

Plant chromium contents measured by INAA and ICP-OES 38 '

VI

List of Tables

f

Pace

Table 1. 11

Analytical features of INAA & ICP-OES ' ^

i

Table 2.11

Common, scientific names, part used and collection areas of studies medicinal plants

25

j_____

Table 2.2 1

Relevant Nuclear Data for determined radionuclides 27i

Table 3.1 11

Elemental concentration (Mean ± SD mg/kg) of SRM 1547 (peach leaves) using INAA ;

. . . . . . . . . . . . . . . . _______ J _____ ... -

Table 3.2r

j

Elemental concentration (Mean ± SD mg/kg) of reference ERM-CD 281 (rye grass) using ICP-OES

---- . J

30

Table 3.31

1

ICP-OES measurement (Mean ±SD mg/kg) of reference material milk powder (ERM-BB150) 30

Table 3.41

Element concentration (Mean ±SD mg/kg) in Sudanese medicinal j plants obtained by INAA

1|

i11

Table 3.511

Element concentration (Mean ±SD mg/kg) in Sudanese medicinal ! .

plants obtained by ICP-OES !

11. . L

VII

Chapter One

IntroductionLI. Medicinal plantsWorldwide, medicinal plants have been used since time immemorial. They have served as

cheaper alternative to orthodox drugs. A great number of research conducted on these medicinal

plants often focus on the organic action of these medicines with little attention going to the

elemental contents. Due to their potential impact on human health, the pharmacological

properties of these medicines must be studied. The pharmacological properties have been

attributed to active chemical contents (Debrah et al.« 201 1). In recent years, there has been a

gradual revival of interest in the use of medicinal plants in developing countries because herbal

medicines have been reported safe and without any adverse side effect especially when

compared with synthetic drugs. Medicinal plants play significant role in providing primary

health care services to rural people and are used by about 80% of the marginal communities

around the world. Besides that, every human needs a daily supply of different types of food

materials to enable a healthy life. However, the productive value of food depends on the quantity

eaten and the extent to which the food is consumed with the required energy,

and vitamins (Hussain et aL, 2013).

in, minerals

Medicinal plants have evolved over the centuries as essential parts of African civilization and arc

widely recognized today as representing its rich cultural and scientific heritage. The increasing

demand for medicinal plant products has renewed interest in the pharmaceutical industry m the

production of herbal health care formulations, herbal-based cosmetic products, and herbal

nutritional supplements. Thus, in addition to serving medical and cultural functions, medicinal

plants in Africa have economic importance. Global and national markets have been growing for

medicinal herbs, and significant economic gains are being realized through the sale of medicinal

plant products ( Dzoyem et al., 2013).

Medicinal plants have been widely used to treat a variety of infectious and non-infectious

ailments (Mukhtar et al., 2008). They come into preparation of various modern drugs or even

they have been used as the principal source of raw materials for conventional drugs in the

developing countries; these plants are easily found in local market. There is great interest in

tracing the essential elements and the composition in medicinal science; it is believed that the

1

great majority of elements are as key components of an essential enzyme svstem or vital bio­

chemical function (Selvaraju et al., 2011).

Sudan has an immense diversity and variation in vegetation and is one ot the richest countries

with regard to phytopharmaca. Although herbal remedies are often perceived as being natural

and, therefore, safe, they are not principally free from adverse effects. While man> investigations

of the quality values of medicinal plants are being reported in the current literature, iess emphasis

has been made on the metal content of herbal products (Ebrahim et al.. 2012).The climate ot

Sudan ranges from completely arid to tropical zones with a wide range of biociimatic regions,

from the almost barren deserts in the North to the tropical rain forests in the extreme South of the

country. The diversity of the climate of Sudan is responsible for its very rich flora. Research on

medicinal and aromatic plants began a long time ago, but this was carried out in a scattered and

unstructured fashion until the establishment of the Medicinal and Aromatic Plants Research

Institute (M A PR I) in 1972 (Eltohami 1997).

1.2. Historical roots of medicine in Sudan

1.2.1. Traditional Sudanese medicine

Sudanese folk medicine represents a unique blend of indigenous cultures of Islamic. Arabic and

African traditions. Consequently, treatments exist for a variety of diseases, both epidemic and

endemic. To face these diseases, people have tapped the environmental resources, e g. plants,

minerals and animal products for the management of their health (Khalid et al.. 2012 > in this

respect, the Sudanese have amassed a large body of curative methods, techniques and recipes.

Readers mav find further recent and detailed information in the descriptive inventorv. whichm/ I r '

appeared in the Atlas of Medicinal Plants series published by Medicinal and Aromatic Plant s

Research (MAPRI). This series includes comprehensive surveys of the medicinal plants Erkavvit.

Nuba Mountains, White Nile, North Kordofan, and Angasana Though not yet investigated

systematically or in depth, there are clues in literature about the bioactivity of medicinal plantv;

and their chemical constituents. Sudanese medicinal plants have been reported to exert

antimicrobial activity against viruses, bacteria, and protozoa (Ahmed et al., 2010). As infection N

with worms or molluscs represent a common affliction in that area, medicinal plants have been

considered for treatment of these infections. Immunomodulatory properties of Sudanese

medicinal plants have also been observed. In this review, we provide an updated overview of the

most important plants used in Sudanese traditional medicines (Khalie et a l . 2012).

2

1.2.2. Overview of medicinal plants in Sudan

The flora of Sudan consists of 3137 documented species of flowering plants belonging to 170

families and 1280 genera. It is estimated that 15% of these plants are endemic to Sudan, The

intersection of cultures and the unique geographical position of Sudan hold great potential for

research in many fields, the most important of which is medicinal and aromatic plants. The

diversity of climates in Sudan results in a rich variety of flora species corresponding to the wide

range of ecological habitats and vegetation zones. In Sudan, it is a common practice to collect

medicinal plants from their natural habitats for home consumption and export. Plants collected

from different localities or geographic regions may have different chemical compositions. This

may be explained by differences in climate, temperature, rainfall, altitude, day length and UV-

radiation, all of which play an important role in plant development and affect the biosynthesis of

secondary metabolites with biological activity. In general, generation of volatile oils appears to

be enhanced at higher temperatures (Khalid et al., 2012). Continuous rainfall can lead to a loss of

water soluble substances from leaves and roots by leaching and also makes collection and drying

more difficult. For example, when peppermint is grown in Sudan under long-day conditions, the

leaves contain high amounts of menthone and menthol with only trace amounts of menthofuran.

whereas peppermint plants grown under short-day conditions contain menthofuran as the major

component. The amount of bitter constituents in Gentiana lutea increases with altitude, whereas

alkaloid contents in Aconitum napellus and Lobelia inflate and essential oils in thymus

peppermint decrease. Pyrethrum delivers the best yield of pyrethrins when cultivated near the

equator and at high altitudes (Khalid et al., 2012).

1.3. Importance of trace elementsTrace element is defined as any element present below -0.1 wt. %. Units such as ppm. ppb. ppt

(parts per million, billion, trillion) are used to describe the concentrations of trace elements in a

system. The human body is composed of elements which can be roughly divided into abundant

elements and trace elements. Abundant elements consist of the major elements that are involved

in the formation of covalent bonds and are important constituents of tissues (oxygen, carbon,

hydrogen, nitrogen, etc.) and of the total body weight, and the semi-major elements account for 3

to 4% of the total body weight. Deficiency of major elements can lead to nutritional disorders,

and their presence in excess can cause obesity (Wada 2004).

3

Essential trace elements of the human body include zinc (Zn), copper (Cu). selenium (Se)

chromium (Cr), cobalt (Co), iodine (1), manganese (Mn), and molybdenum (Mo). Although

these elements account for only 0.02% of the total body weight, they play significant roles, e.g,.

as active centers of enzymes or as trace bioactive substances. A major outcome of trace element

deficiencies is reduced activity of the concerned enzymes (Wada2004). However, since each

trace element is related to so many enzymes, deficiency of a single trace element is often not

associated with any specific clinical manifestations, but rather manifests as a combination of

various symptoms. Because of the presence of trace elements in very small amounts and the

absence of specific clinical features associated with their deficiency, often difficult lor clinicians

to identify deficiencies of some particular trace elements ( Wada 2004).

1.3.1. ChromiumCr plays an important role in diabetes treatment. It is an important element required for the

maintenance of normal glucose metabolism. The function of Cr is directly related to the

function of insulin, which plays a very important role in diabetes. Cr deficiencies in diet

produce elevated circulating insulin concentrations, hyperglycemia, hypercholesterolemia,

elevated body fat, decrease sperm counts, reduce fertility, and shorten life span. Cr is found in

the pancreas, which produces insulin. One usable form of Cr is the Glucose Tolerance Factor

(GTF). The important constituent of GTF is Cr which helps in potentiating of insulin. Chronic

exposure to Cr may result in the liver, kidney and lung damage (Zetic et ai, 2001)

1.3.2. Copper

C'u In humans is necessary for the development of connective tissue, nerve coverings, and bone.

It is also participates in both Fe and energy metabolism .Cu acts as a reluctant in the enzymes

superoxide dismutase and several others oxidizes that reduce molecular oxygen. There is about

80 mg of Cu in the adult body and median intake of Cu ranges between 1.0 and 1.6 mg/day in

adults. Good sources of dietary Cu are liver and other organ meats, oysters, and nuts, seeds dark

chocolate and whole grains. Cu deficiency in humans is rare, but when it occur leads to anemia,

leucopenia and inclusive osteoporosis in children. Excessive dietary Zn can cause Cu deficiency.

Chronic Cu toxicity is rare in humans, and mostly associated with liver damage. Acute Cu

intoxication leads to gastrointestinal effects characterized by abdominal pain, cramps, nausea,

diarrhea, and vomiting (Fraga 2005)

4

1.3.3. IronIron is the most abundant trace element in human bodv, a structural component in heme protein s

hemoglobin, myoglobin, and cytochrome-dependent proteins (Griffiths 2007).A large quantity is

also stored in proteins like ferritin and hemosiderin. Its role is in oxido-reduction. by conversion

of the Fe (II) and Fe (III) forms. The free ion would cause oxidative stress. Iron deficiency leads

to severe anemia. Excess iron can give gastrointestinal problems, vomiting, and diarrhea, ending

with cirrhosis for chronic exposure. It may also be carcinogenic. Hemochromatosis is a genetic

disease in which iron is absorbed in excess from the diet and accumulates in different tissues

with altered distribution (Griffiths 2007).

Iron interacts with other metals: copper, manganese, zinc, and chromium. Iron-binding proteins

can bind other cations, such as manganese, zinc, and vanadium, thereby contributing to their

transport (Ballatori 2002).

1.3.4. MagnesiumMagnesium is an intracellular ion which acts as a cofactor in oxidative phosphorylation in the

synthesis or utilization of ATP (e.g. in muscle contraction). Many of the adhesion molecule

I.e. proteins involved in direct cell-cell contact have magnesium located at the binding site of

the molecule. Its plasma concentration relative to calcium affects nerve transmission and

muscular contraction. The concentration of substances likes fattv acids, phvtate. and

phosphorous in the gut contents affects magnesium absorption. Its absorptive pathway is

common with calcium (Makrides and Adelaide 2010).

Mg deficiencies encourage deposits of unabsorbed minerals upon heart muscles., kidneys and

arteries. The kidneys are very efficient at maintaining body levels, but not in cases where the diet

is deficient. Mg acts in the cells of all the soft tissues, where it is part of the protein-making

machinery and is necessary for the release of energy. A fair amount of information on these

elements and their roles in various physiological processes, their ways of functioning and

necessity would be of paramount importance to understand the progression of various diseases

and their remedies (Selvaraju et al., 2011).

1.3.5. Zinc

Zn is another essential, relatively non toxic and enzymatic metal for both plant and animal. Zn is

necessary for the growth and multiplication of cells (enzymes responsible for DNA and RNA

synthesis), for skin integrity, bone metabolism and functioning of taste and eyesight. Zn plays an

5

important role in production, storage, and regulation of insulin, Zn deficiency is characterized b>

recurrent infections, lack of immunity and poor growth. Growth retardation, skin changes, poor

appetite and mental lethargy are some of the manifestations of chronicallv Zn-deficient. human

subjects. The high concentration of Zn in flowers suggests its possible use m sex tome, treatment

of worms, eve trouble and skin disease. Zn is essential for the function of the immune svstem

cells and Zn has been shown to be effective in the treatment of common cold (Mossad a a/..

1996). Zn is also required for the activity of more than 100 enzymes associated with

carbohydrate and energy metabolism, protein degradation and synthesis (Selvaraju ei ui., 201 1).

1.3.6. CalciumCalcium is an important trace element because of its role in bones, teeth, muscular system and

heart functions. It is required for the absorption of dietary vitamin B. for the synthesis of the

neurotransmitter acetylcholine, for the activation of enzymes such as the pancreatic lipase

(Lokhande et al., 2010). Calcium is necessary for the coagulation of blood, the proper

functioning of the heart and nervous system and the normal contraction of muscles. Its most

important function is to aid in the formation of bones and teeth (Saraf and Samant 2013 ).

1.3.7. PotassiumPotassium ions are the most abundant cations in the human body. It is extremely important for

the cells in the body. It is essential for smooth flow' of communication signals from cell to cell

and its deficiency can contribute to diseases like stroke, heart problem, diabetes and

hypertension. It acts in the intercellular fluid as the primary ion. Potassium together with sodium

helps to regulate the water balance within the body. It regulates the transfer of nutrients to th v

cell, transmits electrochemical impulses and is necessarv for normal growth and enzvmaticA w w

reactions. The average human consumes potassium up to 7 gm a day and has a store of

some 140 gm in the human body, mainly in the muscles. K is of importance as a diuretic

(Raman et al., 2013).

1.3.8. Manganese

The kidney and liver are the main storage places for the manganese in the body. Mn is essential

for normal bone structure, reproduction and the normal functioning of the centra! nervous

system. Its deficiency causes reproductive failure in both male and female. Mn is also important

for several enzymatic processes. It helps in eliminating fatigue and reduces nervous irritability

(Lokhande et al., 2010).There are two enzymes known to contain Mn; pyruvate carboxylase and

6

superoxide dismutase (Niamat et al., 2012). Apart from physiological importance experimenta

data have pointed out the pharmacological implication ot this element especial 1\ m

prevention and treatment of diabetes mellitus (Debrah et a/.,(2011).

1.3.9. CobaltCobalt is an essential trace element and forms part of the active site of V itamin B:: . The amount

of cobalt required in the human body is very small and it contains only about 1 mg, Cobalt salts

in small doses have been found to be effective in correcting mineral deficiencies m certain

animals. But in large doses it is carcinogenic. There are no established criteria limits for cobalt m

medicinal plants (Raman et al., 2013),

1.3.10. StrontiumStrontium (Sr) is a mineral with a reported effect on the reduction of bone fracture risk.

Strontium is able to substitute for calcium in hydroxyapatite (bone crystal}. The uptake of high

strontium concentrations is generally not known to be a great danger to human health In one

case someone experienced an allergic reaction to strontium, but there have been no similar cases

since. For children exceeded strontium uptake may be a health risk, because it can cause

problems with bone growth. When strontium uptake is extremely high, it can cause disruption of

bone development. But this effect can only occur when strontium uptake is in the thousands ot

ppm range. Strontium levels in food and drinking water are not high enough to be able to cause

these effects (http://www.lenntech.com/periodic/elements/sr.htm).

1.4. Role of trace elements in medicinal plantsTrace elements play a very important role in the formation of the active chemical

constituents present in medicinal plants. However, a direct correlation between elemental

composition of the medicinal plants and their curative properties has not been established yet.

The quantitative estimation of various trace element concentrations is important for

determining the effectiveness of the medicinal plants in treating various diseases and also

to understand their pharmacological action. The elemental status of plant is necessary for new

drug development research in raw herb. Therefore, proper scientific investigations are required

to explore the exact medicinal potential of plants. This is very important not only for the

safety of consumers, but also for medical advisors (Selvaraju et aL, 201 1).

Most of the trace elements are essential to life, but thev can have deleterious effects when' r'

present in excess. Death and disease related to acute or chronic exposure have been

7

documented for some of the essential trace elements. It is essential to know the trace elemental

concentration in medicinal plants from the point of view of’ nutritional requirement and

intoxication risk associated with their consumption. The effects and influence of trace elements

on administration of medicinal plants is also essential to understand the pharmacological

action of herbs and to decide the dosage of the herbal drugs prepared from these plant

materials (Raju et al., 2013).

The elemental composition of many plants is known. It will be very interesting to determine their

trace elements’ status. It is surprising to note that many curative effects of medicinal plants used

in the traditional system of medicines are due to the presence of very minute quantities of trace

elements. Important constituents of the body such as enzymes are intimately associated with the

chemical elements. Elements, particularly essential trace elements play both curative and

preventive roles in fighting diseases such as Fe in anemia and iodine in goiter. The deficiency of

trace elements in human subjects can occur under most practical dietary conditions. Many

diseases which have been considered incurable may now possibly be treated by balancing the

disequilibrium of these elements in the human body (Shirin et al., 2009).

1.5. Instrumentation

1.5.1. Instrumental Neutron Activation Analysis (INAA)The accurate determination of trace concentrations of elements in complex matrices such as

rocks, soils, plants and sediments are very important in both mineral exploitations and soil

fertility mapping. Methods that can be used for the analysis materials such as atomic absorption

spectrometry (AAS), inductively coupled plasma-atomic emission spectrometry (ICP-AES) or

mass spectrometry (ICP-MS), all of which require dissolution and sometimes subsequent

chemical treatment of the sample to ensure full dissolution with the inherent risk of

contamination .However, a method with widest acceptance and unique advantages in areas such

as sensitivity, speed, precision, cost, low matrix effects, and preservation of sample known as

Instrumental Neutron Activation (1NNAA) (Funtua et al., 2012).

INAA is one of the most reliable methods for measuring the elements, regardless of

chemical form. It does not require complicated sample digestion steps, which minimizes

the possibility of analyte loss and contamination. It is less strongly affected by the matrix

of the sample because of the high penetration power of neutrons and gamma rays and is

not affected by the chemical and physical states of the analyte elements (Kim e/a/.. 2013).

8

INAA has been commonly used to perform multi elemental analysis in a variety of

environmental studies due to its sensitivity and accuracy (IAEA-1215. 2001). Furthermore.

INAA based on the relative method is used to maintain the high level of accuracy required.

However, it is important to adjust experimental parameters for an optimization and to give

results within statistical control. Manv elements can be determined with higher sensitivity b\

optimizing the irradiation, decay and counting times (El-Taher and Alharbi 2013). Also i\A A

has been used for the assessment of elemental composition in soils successfully (Haciyakupogiu

et al., 2014). NAA is considered as the referee method of choice when new procedures are being

developed or when other methods yield inconsistent results do not agree. Nevertheless, until

recently, its applicability was not possible in many cases and in many matrices where final

sensitivity was affected and reduced by the limited performance of detectors and electronics.

Very recently, a new generation of digital signal processing-based germanium y-ray

spectrometers has provided unprecedented superior performance (Hamidatou et al.. 2013). This

new technology allows dramatic improvements on the previous analogic electronic chains,

giving a combination of high resolution, throughput, count rate stability and long-term stability

of both resolution and peak shape. In applications involving high or widely varying count rates,

the new systems allow the best resolution and peak stability, providing excellent y spectra for an

accurate analysis of samples of different origin and composition (Kharfi 2013 ).

Neutron activation analysis (NAA) is a nuclear process used for determining the concentrations

of elements in a vast amount of materials. NAA relies on excitation by neutrons so that the

treated sample emits gamma-rays. It allows the precise identification and quantification of the

elements, above all of the trace elements in the sample. NAA has applications m chemistry

but also in other research fields, such as geology, archaeology, medicine, environmental

monitoring and even in the forensic science (Hamidatou et al., 2013).

1.5.1.1. Basis principlesThe sequence of events occurring during the most common type of nuclear reaction used for

NAA, namely the neutron capture or (n, y) reaction, is illustrated in Figure 2.1. Creation of a

compound nucleus forms in an excited state when a neutron interacts with the target nucleus via

a non-elastic collision. The excitation energy of the compound nucleus is due to the binding

energy of the neutron with the nucleus. The compound nucleus will almost instantaneously de-

excite into a more stable configuration through emission of one o> more characteristic prompt

9

gamma rays. In many cases, this new configuration yields a radioactive nucleus which also dc-

excites (or decays) by emission of one or more characteristic delayed gamma rays, but at a

much lower rate according to the unique half-life of the radioactive nucleus Depending

upon the particular radioactive species, half-lives can range from fractions of a second to several

years (Kharfi 2013),

In principle, therefore, with respect to the time of measurement, NAA falls into two categories:

prompt gamma-ray neutron activation analysis (PGNAA). where measurements take

place during irradiation. The PGAA technique is generally performed by using a beam

of neutrons extracted through a reactor beam port. Fluxes on samples irradiated in beams

are in the order of one million times lower than on samples inside a reactor but detectors

can be placed very close to the sample compensating for much of the loss in sensitivity

due to flux. The PGAA technique is most applicable to elements with extremely high

neutron capture cross-sections (B, Cd, Sm, and Gd); elements which decay too rapidly to

be measured by DGAA; elements that produce only stable isotopes (e.g. light elements):

or elements with weak decay gamma-ray intensities. 2D, 3D analysis of (main ) elements

distribution in the samples can be performed by PGAA (Kharfi 2013),

Delayed gamma-ray neutron activation analysis (DGNAA), where the measurements

follow radioactive decay. DGNAA (sometimes called conventional NAA) is useful for

the vast majority of elements that produce radioactive nuclides. The technique is flexible

with respect to time such that the sensitivity for a long-lived radionuclide that suffers

from interference by a shorter-lived radionuclide can be improved by waiting for the

short-lived radionuclide to decay or quite the contrary, the sensitivity for short-lived

isotopes can be improved by reducing the time irradiation to minimize the interference of

long-lived isotopes (Hamidatou et ah, 2013),

1 0

neutron b -pkirtjc If

* * m •* * *ca pfu re

# *

#■ * * * ♦ ' ■ # *

&

A yZ *

** ** •*/ - VI* * * 4 *• * # * •"

• # <

UJor npo uncinucleus

A+12 X’

iv e

A*121X

rofri|;»f ciarnfriai actatiori POAA

\decay

\

A* 1Zi1 X A-1

7 - 1k t o 11 ijM-h

X* \ .jtjcay lyamriv radiation

NAA

Figure 1.1: Diagram illustrating the process of neutron capture by a target nucleus followed by

the emission of gamma rays

This selectivity is a key advantage of DGNAA over other analytical methods. In most cases, the

radioactive isotopes decay and emit beta particles accompanied by gamma quanta of

characteristic energies, and the radiation can be used both to identify and accurately quantify the

elements of the sample. Subsequent to irradiation, the samples can be measured instrumentally

by a high resolution semiconductor detector, or for better sensitivity, chemical separations can

also be applied to reduce interferences. The qualitative characteristics are: the energy of the

emitted gamma quanta (Ey) and the half life of the nuclide (Tv,). The quantitative characteristic

is: the 1 intensity, which is the number of gamma quanta of energy Ey measured per unit time

(Hamidatou et al., 2013). For example, consider the following reaction:58Fe + n 59 Fe + Beta’ + gamma rays58 59Fe is a stable isotope of iron while Fe is a radioactive isotope. The gamma rays emitted

during the decay of the 39Fe nucleus have energies of 142.4, 1099.2. and 1291.6 KeV.

and these gamma ray energies are characteristic for this nuclide (Be et al.. 2004). The (n. y)

reaction is the fundamental reaction for neutron activation analysis

11

The probability of a neutron interacting with a nucleus is a function of the neutron energy Thi s

probability is referred to as the capture cross-section, and each nuclide has its own neutron

energy-capture cross-section relationship. For many nuclides, the capture cross-section is

greatest for low energy neutrons (referred to as thermal neutrons). Some nuclides have greater

capture cross-sections for higher energy neutrons (epithermal neutrons). For routine neutron

activation analysis we are generally looking at nuclides that are activated by thermal neutrons.

The most common reaction occurring in NAA is the (n. y) reaction, but also reactions such as (n.

p). (n, a), (n, n') and (n, 2n) are important. The neutron cross section, a. is a measure for the

probability that a reaction will take place, and can be strongly different for different reaction

types, elements and energy distributions of the bombarding neutrons. Some nuclei, like

‘ "U are fissionable by neutron capture and the reaction is denoted as (n, 0- yielding fission

products and fast (highly energetic) neutrons (Hamidatou et a l , 2013).

I.5.I.2. INAA how does it work?

A gamma-ray spectroscopy system consists of a detector (and high voltage pow er supply for the

detector), pre amplifier, spectroscopy amplifier, analog-to-digital converter, multi-channel

analyzer, and an output device. A sample is presented to the detector (Ge in the case of gamma-

ray analysis). In order to minimize thermal noise the detector is kept at cryogenic temperatures

(liquid nitrogen, temperature = 77K). The initial signal is very small and the pre-amplifier,

attached directly to the detector, amplifies this signal. The signal is shaped by the spectroscopy

amplifier and then converted from an analog to a digital signal by the analog-to-digital converter

The results are stored in digital form (multi-channel analyzer). In modern gamma-ray

spectroscopy systems the high-voltage power supply, spectroscopy amplifier, analog-to-digital

converter, and multi-channel analyzer are combined into a single module. A computer is used to

visually show' the resulting spectrum and to do calculations on the spectrum. Various algorithms

are used to determine the shape and energy of each gamma-ray peak present in a spectrum and to

determine the area encompassed by the peak (i.e., the gamma-ray intensity). Subsequent decay,

interference (if required), fluence, fission product corrections, and comparison with a standard

lead to a quantitative analysis figure 1.2.

12

Figure 1.2: Flow chart for a gamma-ray spectroscopy system

1.5.1.3. Neutrons sources26 ^ c ^( j ^ a ,J) f ■; ^

• Isotopic neutron sources'. like Ra (Be). ' Sb (Be), “ ‘Am (Be). J Cf. The neutrons have

different energy distributions with a maximum in the order of 3--4 MeV; the total output iS

typically KT-lO's GBq'or, for 252Cf, 2.2* 10

• Particle accelerators or neutron generators: The most common types are based on the

acceleration of deuterium ions towards a target containing either deuterium or tritium, resulting^ ^ 'i

in the reactions _H(2H,n) He and H(2H,n) He. respectively. The first reaction, often

denoted as (D.D). yields mono-energetic neutrons of 2.5 MeV and typical outputs m the order

p j I

“s' g' (Hamidatou ei ai. 013).

of 108-1010 -s ; the second reaction (D,T) results in monoenergetic neutrons of 14.7 MeV

and outputs of 109— 1011 s 1 (Kharfi 2013),

'Nuclear research reactors: The neutron energy distribution depends on design of the reactor

and its irradiation facilities. An example of an energy distribution in a light water moderated

reactor the major part of the neutrons has a much lower energy distribution that in isotopic

sources and neutron generators. The neutron output of research reactors is often quoted as

neutron fluence rate in an irradiation facility and varies, depending on reactor design and15 1 1 > • ^

reactor power, between 10 and 10 m'V . Owing to the high neutron flux, experimental

nuclear reactors operating in the maximum thermal power region of 100 kW -10 MW with a

-i

j ^ J J • «J

maximum thermal neutron flux of 10-10 neutrons cm “s are the most efficient neutron

sources for high sensitivity activation analysis induced by eoitherrna! and thermal neutrons. The

reason for the high sensitivity is that the cross section of neutron activation is high in the thermal

13

region for the majority of the elements (Hamidatou et ai. 2013). There is a wide distribution ot

neutron energy in a reactor and, therefore, interfering reactions must be considered, in order to

take these reactions into account, the neutron spectrum in the channels of irradiation should be

known exactly. E.g. if thermal neutron irradiations are required, the most thermalized channels

should be chosen. Although there are several types of neutron sources (reactors, accelerators, and

radioisotope neutron emitters) one can use for NAA. nuclear reactors with their high fluxes of

neutrons from uranium fission offer the highest available sensitivities for most elements.

Different types of reactors and different positions within a reactor can vary considerably with

regard to their neutron energy distributions and fluxes due to the materials used to moderate (or

reduce the energies of) the primary fission neutrons. This is further elaborated in the title

"Derivation of the measurement equation". In our case, the NAA method is based on the use of

neutron flux in several irradiation channels of the research reactor (Hamidatou et ai. 2013).

In many cases NAA can be performed nondestructive!}', this analysis mode being termed

instrumental NAA (INAA). In the cases where the induced radionuclides of trace

elements are masked by matrix activity, a radiochemical separation (i.e. a post-irradiation

procedure) is mostly used to eliminate matrix activity or to separate the radionuclides of interest

in the so called radiochemical NAA (RNAA) (IAEA-TECDOC-1121-1999).

1.5.2. The General Equation of Neutron Activation Technique

LetN be the number of radioactive nuclei produced during irradiation t. a be the cross-section of

the reaction, O the neutron flux, n number of target nuclei and A the decay constant of the

radionuclide formed (Shaddad 1995).Then we have the following differential equation

dN_~dt

— <£>cr n - AN

Where the first term on the R.H.S describes the increase of N because of the activation process,

while the second term given the decrease of N due to decay

The general solution of such differential equation is:

N = e{- A,)[c + <7 n J<D(f) e(k,)dt

Where the flux <t> is assumed to be time dependant and C is a constant of integration. However

if the flux is constant, i.e. 0= O0 and assuming the initial condition N=0 at t =0. then we have

N(t) = Oocr /7(1 - eA

(-;.o(3)

14

(4)

The activity at time t will be

A{t) = XN{t) = <£>ocr n - e {-At )

After the end of irradiation, A decrease exponentially and after a time ti following end of

irradiation we have

Alt1 Alt) e -A lt=t(5)

If the activity measurement is preformed during the time interval between tj and t;. then the

expected number of decay events Ac will be given by:

A<3> o cr n e (- A e (-*(/ - t ,)) 1 (- / _ ))

c A(6)

Where, t=t, is the irradiation time, ti-t=tw is waiting time and t;-ti is the counting time

Accordingly equation (6) can be written as

AO oct n l (- >. *, ) 1 e I-'Ak ))

c x (7)

Clearly, the average number of counting decay events Nc will be less than A, due different

effects such as the efficiency of the detector£ for the particular energy and for the particular

counting geometry, and the intensity of the measured gamma line 1 so :

K = eIAc

Also the number of target nuclei is given by

( 8 )

n =N

a

Wmf(9)

Where m = the mass of the element in the sample. W = the atomic weight. Na =Avoaadro’s

number=6,02.10“ mole"1, f = the relative isotopic abundance ofthe target isotope.

From the equations (7), (8) and (9) we have for the basic equation of neutron activation analysis:

-i

Ac =N am f Q o a e I (l e (- / u ) 1 e

W X ( 10)

15

1.5.3. Types of standardizationFor the determination of element concentrations in NAA three types ot standardization

(calibration) can be used:

• relative (using synthetic, mostly multi-element standards)

• single-comparator, most frequently employing the so called kf,-standardization

• Absolute (parametric).

Since unacceptable uncertainties are still associated with the values ot nuclear

parameters, namely activation cross sections o0, resonance integrals 10. gamma ray emission

probabilities y. and isotope abundances 0 (in order of decreasing importance), the absolute

standardization is used only rarely and will not be dealt with in the present report (IAEA-

TECDOC-1121-1999).

In the relative standardization method, a chemical standard with a known mass of the

element is co-irradiated with the sample of a known mass and both are counted, usually in the

same11 “

eometrical arrangements with respect to the HPGe detector, so that the absolute

efficiency of the detector need not be determined. When short-lived radionuclides are to be

measured both the standard and sample may be irradiated separately using the same reactor

conditions, usually with a monitor of the neutron fluence rate.

In the case of relative standardization, the analysis results are traceable to the materials used in

the preparation of standards. Depending on the purity and stoichiometry of the compounds used,

traceability to the mole can be established (IAEA-TECDOC-1 121-1999 ).

The concept of the k0-standardization in NAA. one of the most frequently used single-

comparator (mono-standard) methods, is based on co-irradiation of the sample and a neutron

fluence rate monitor and the use of an experimentally determined composite nuclear constant kft

Details of the ^.-standardization have extensively been described in the literature (De Cone

1987), In the case of ^-standardization; the analytical results are linked to the k«-factors.

absolute detector efficiency and neutron spectrum characteristics. The k0-factors have been

reliably determined in two independent measurements which were related to purity and

stoichiometry of various materials (IAEA-TECDOC-1 121-1999). The absolute detector

efficiency calibration is routinely performed using internationally recognized radioisotope

standards. For determining the neutron spectrum characteristics, internationally recognized

16

certified reference materials for neutron dosimetry are available, (high purity metals or Ai

alloys containing certified amounts of Au. Co. In and U) (IAEA-TECDOC-1121-1999),

1.5.3.1. The ko-comparator methodThe ko-based neutron activation analysis (ko-NAA) technique, developed in 1970s. is being

increasingly used for multi-element analysis in a variety of matrices using reactor

neutrons (De Corte et at., 1987). In our research reactor, the ko-method was successfully

developed using the Hogdahl formalism. In the ko-based neutron activation analysis the

evaluation of the analytical result is based on the so-called k0- factors that are associated with

each gamma line in the gamma-spectrum of the activated sample (Hamidatou et at., 2013 ). These

factors replace nuclear constants, such as cross sections and gamma-emission probabilities, and

are determined in specialized NAA laboratories. This technique has been reported to be

flexible with respect to changes in irradiation and measuring conditions, to be simpler than the

relative comparator technique in terms of experiments but involves more complex formulae and

calculations, and to eliminate the need for using multi-element standards. The ko-NAA

technique, in general, uses input parameters such as ( 1) the epithermal neutron flux shape factor

(a), (2) subcadmium-to-epithermal neutron flux ratio (/), (3) modified spectral index r (a) vT„

To, (4) Westcotf s g(Tn)-factor, (5) the full energy peak detection efficiency (£p),and (6) nuclear

data on Qofratio of resonance integral (Io) to thermal neutron cross section (Go) and k,,. The

parameters from (1) to (4) are dependent on each irradiation facility and the parameter (5) is

dependent on each counting facility. The neutron field in a nuclear reactor contains an epithermal

component that contributes to the sample neutron activation (Mustra et at., 2003) Furthermore,

for nuclides with the Westcotf s g (Tn) factor different from unity, the Hogdahi convention

should not be applied and the neutron temperature should be introduced for application of a more

sophisticated formalism (De Corte et at., 1987) the Westcott formalism. These two formalisms

should be taken into account in order to preserve the accuracy of ko-method. The ko-NAA

method is at present capable of tackling a large variety of analytical problems when it comes to

the multi-element determination in many practical samples.

I.5.4.2. Applications, advantages and limitations of NAAWhile liquid samples (if certain precautions are taken) can be analyzed by INAA, solids are

the matrix of choice for this technique. Virtually any material can be analyzed and limitations

are largely due to the chemistry of the matrix. For example, it would be difficult to obtain low

17

detection limits for a sample of pure iron because given the half-life (44.6 days) of Te„ the

sample will have a high background for an extended period of time and shorter half-life

isotopes will be gone from the sample before this background is reduced. Examples of the ty pe

of materials that can be analyzed by 1NAA are:

• Rocks, minerals, and soils

• Atmospheric aerosols

• Archaeological artifacts

• Tree rings

• Dust in ice cores

• Hair, nails, skin, etc.

• Plant and animal matter

• Coal

Advantages of NAA:

Activation analysis measures the total amount of an element in a material without regard to

chemical or physical form and has the following advantages:

(1) Samples for NAA can be liquids, solids, suspensions, slurries, or gases. Samples do not have

to be put into solution or vaporized.

(2) One of the most important a advantage of NAA is that it is nearly free of any matrix

interference effects because the atoms of matrix are composed of H. C, O, N, P. and Si that do

not form any radioactive isotopes. This makes the method highly sensitive for measuring trace

elements, thus the vast majority of samples are completely transparent to both the probe (the

neutron) and the analytical signal (the y-ray) (Verma 2007).

(3) NAA is nondestructive in that the integrity of the sample is not changed in any manner by

pre-chemistry or the addition of any foreign materials before irradiation - thus the problem of

reagent-introduced contaminants is completely avoided (Verma 2007).

(4) NAA requires only small amounts (100-200 mg) of sample material.

(5) The analytical approach for NAA for most elements of interest is primarily an instrumental

technique and does not require any post irradiation chemistry (Verma 2007).

(6) NAA is a multi-element analytical technique in that many elements can be analyzed

simultaneously in a given sample y-spectrum without changing or altering the apparatus as is

necessary in atomic absorption.

18

(7) NAA is fast in that many samples can be irradiated at a given time for main elements and

counted later on a given decay schedule.

(8) Sensitivitv to trace elements: The sensitivity obtained by activation analysis is a lunctior v > i

the neutron cross-section of the element in question, available neutron flux, length of irradiation,

resolution of the detector, matrix composition, and the “total’" sample size. Hence, increasing

neutron fluxes, increased irradiation times, and the major advances in nuclear detector

technology in the areas of increased efficiency and resolution have pushed the detection limits ot

most elements of interest to the very low levels.

Limitations of"NAA are:

V1) Interferences can occur when different elements in the sample produce y-ray s ot nearly the

same energy. Usually this problem can be circumvented by choosing alternate v-rays for these

elements or by waiting for the shorter-lived nuclide to decay prior to counting. The limit of

detection for a particular element will depend upon the measured count rate of the y-ray being

monitored and the background upon which that y-ray peak sits. The measured count rate for a

given isotope can be increased by (a) increasing the detector efficiency (moving the sample

closer to the detector) (b) increasing the irradiation time and (c) decreasing the decay time. The

sensitivity of the measurement can in many cases be improved by increasing the overall signal or

total number of counts. This is accomplished by simply increasing the measurement time.

2) The limit of detection for an element can be lowered if we increase the ratio of the activity of** ++

the y-ray of interest to the background through any combination of steps (a), (b ) or (c) mentioned

in (1). Conversely, changing the detector efficiency, irradiation time, or decay time to cause a

lower peak-to-background ratio will worsen the detection limit. The change in -to-

background ratio is primarily a function of the activity of other isotopes produced in the neutron

irradiation of the sample.

3) The most important limitation is that it takes a lot of time to complete a full analysis Because

all radioactive isotopes have different half-life times, they can be divided into three categoric s:

short-lived nuclides (half-life time from less than Is up to a few hours), middle-living nuclides

(half-life time of a few hours up to several days), and long-living nuclides (half-life time of

several days up to weeks, months or even years). When one wants to measure the elements

which form long half life radionuclides, one has to war for a fewr weeks m order that the

19

nuclides with short- and middle half-life times can decay and should not cause any interference,

and make the detection limits better.

A few elements like Pb, Cu, Al, P, S, etc. have small capture cross-sections and short radioactive

half-lives and are thus difficult to detect. The XRF technique has an advantage over NAA

technique due to these reasons (Verma 2007).

1.5.4. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES):

Inductively coupled plasma-optical emission spectroscopy (ICP-OES) is a powerful tool

for the determination of metals in a variety of different sample matrices. With this technique,

liquid samples are injected into a radiofrequency (RF)-induced argon plasma using one of a

variety of nebulizers or sample introduction techniques (Boss and Fredeen 1997). The sample

mist reaching the plasma is quickly dried, vaporized, and energized through collisional excitation

at high temperature. The atomic emission emanating from the plasma is viewed, collected with a

lens or mirror, and imaged onto the entrance slit of a wavelength selection device. Single

element measurements can be performed cost effectively with a simple monochromator-

photomultiplier tube (PMT) combination, and simultaneous multi-element determinations are

performed for up to 70 elements with the combination of a polychromators and an array

detector. The analytical performance of such systems is competitive with most other inorganic

analysis techniques, especially with regards to sample throughput and sensitivity (Ghosh et

al.. 2013).

The fundamental operating principle governing the ability of an inductively coupled plasma

optical emission spectrometer to analyze a sample is the ability of the atoms constituting a

sample to emit light at certain wavelength (Fig 1.3).

20

Digital Da

OpticalPath

ji_i i - •

b , rv

\

\Detector

Torctv

Nebulizer &Spray Chamber

.a Captureand Instrument

ControlI jJ! !r — vIb

HCP

Plasma Gas Auxiliary Gas

NebulizerGas

■Sample

Figure 1.3 Schematic representation of a radial ICP-OES

m

Exoit i o n«Ato nria i mission

Fig 1.4 The excitation, relaxation and subsequent emission of light from electrons, at

wavelengths of 330nm and 590nm, in the sodium atom

The ability of atoms, or ions, to emit light is derived from the ability of the plasma to

excite atoms, or ions. Excitement of an atom or ion occurs in the case of the SC P. by absorption

of thermal energy by atoms, or ions, causing electrons to undergo transitions to higher

21

[ w v V * Ienergy orbitals (Fig 1.4). As the excited electrons return to the ground-state energ}

energy is emitted in the form of photons of defined energv

Each element has a unique emission spectrum derived from ns unique electronic

configuration. The emission wavelengths associated with each element are derived from ihe

difference between the energy levels involved in each of the orbitals that partake in the energ}

transitions of the electron. The number of emission wavelengths, associated with a particular

atom or ion, will increase with an increase in the number of electrons associated with the

nucleus Once emission spectra have been generated, these spectra have to be detected and

recorded (Downer 2008). This is accomplished writh the use of a spectrometer, which splits

the composite radiation emitted by the sample into separate wavelengths and measures the

intensity of the desired wavelength.

ICP-OES is a fast, accurate, precise and relatively easy to use multi-element analytical technique.

The calibration curves generated are linear over approximately five orders of magnitude. T he

practical limits of quantification can be as low as lOOng.mL^.This technique is most suitable for

analyzing elements in the concentration range of O.lto I0,G00|ig.g~'( which translates to 0.01%

to 100% (by weight) in an actual solid sample (Downer 2008).

The following is a list of some beneficial characteristics of the ICP source (Ghosh et al. 2013)

High temperature (7000-8000 K)

High electron density (1014-1016cm3)

Appreciable degree of ionization for many elements simultaneous multi v lement

capability (over 70 elements including P and S)

• Low background emission and relatively low chemical interferences

• High stability leading to excellent accuracy and precision

• Excellent detection limits for most elements (0.1 -100 ng mL)

• Wide linear dynamic range (LDR) (four to six orders of magnitude)

• Cost-effective analvsis

22

Table 1.1 Analytical features of INAA & ICP-OES

Analytical features11

il

INAA j ICP-OES|

l---------------------------------------------

Accuracy11

Excellent j Excellent!i

LOD1

Excellent Goodiii

ii

Sample Typej

solid & liquid : Liquid, i I !

j... ............... i .

Multi-elemental1

i

i

Yes | Yes1 1

1

i

Matrix Effects Low | Mediumi]i

Spectral Interference Low I High1

i1i

Detection LimitsL

0.001-1 ug/g i-30ng/mi1

i4

1i

________ {

Instrument Priceili

i

More than $250.0000 j $100,000 to $250,00011111

23

Chapter Two

Material and Methods2.1. Sample collectionFourteen popular Sudanese medicinal plants were collected from a local market in

Sudan. Botanical identification and authentication of the collected species with

deposition of herbarium specimens have been done by the Medicinal and Aromatic

Plants Research Institute (MAPRI) - National Center for Research-Sudan. Common,

scientific names and collection areas of studies medicinal plants are given in Table2.l.

2.2. Sample drying and homogenizing

Samples were dried at room temperature before transportation to the laboratory. There,

freeze drying was applied at 101 °C sample temperature (Christ-Heraeus Beta freeze

dryer, Osterode, Germany) for four days until weight constancy was reached. Aliquots

of the plant material were cut into small pieces using a ceramic knife and subsequently

ground and homogenized using an agate ball mill. The resulting fine powder was used

for analysis (Ebrahim et al., 2012).

2.3. ICP-OES measurement

2.3.1. Sample preparation

The dried and homogenized samples were properly weighed into quartz vessels (around

100 mg). Subsequently, 1 mL HNO3, suprapure, sub-boiling distilled (Merck.

Darmstadt) was added. The vessels were closed and introduced into a pressure digestion

system (Seif, Unterschleissheim) for 10 h at 1701C. The resulting clear solutions were

diluted to 10.00 mL with Milli-Q H20 (Ebrahim et al., 2012).

24

Table 2.1: Common, scientific names, part used and collection areas of studies medicinal plants

Botanical namei

Local namei■ FamilyiPart used Collection area

Acacia nilotica (L.) Willd. Ex Del.

El-Garad. . . . . . . . ------------- r

Mimosaceae ' Fruits Khartoum Nilei

! Bank1

Acacia Senegal (L.) Willd.

-------------- 1--- --- rAl-hashab Fabaceae- ! Lxudates and , Al Obeid

!! Mimosoidae Woods

Balanites aegyptiaca (L.)Del

Laloub1

1

Balanitaceaciiij

Fruits and Gedarili; Seeds! Seeds Ai l awCajanus cajan (L.)Millsp. Aladsia ' Fabaceae-

PapilionoidaeCapsicum frutescens L.

tShatta Solanaceae

!fruits Khartoum Nile

bankCitrullus colocynthis (L.)Schrad,

Al-handal1------------

Cucurbitaceae Fruits and West Omdurman Seeds

Cucurbita maxima L. Al Garah Aseli I Cucurbitaceae j Seeds Sinnar:

!

CymbopogonproximusSt—

Maharaib Poaceae i Leaves Butanai_____________________________________________________________________________________________________

Foeniculum vulgare P .

M ill.Alshamar Apiaceae \ Whole plants i Dongola

11L

Guiera senegalensis J.F.Gmel.

Gubeish Combretaceae"

Leaves Tandalti

Stems Abu FlamedHaplophylumtuberculata Flazai

Rutaceae

Lawsonia inermis L.- --- |

HennaJ

iLvthraceae 1 Leaves Khartoum localw’ 1i

marketNieella sativa L.

11______________________ 1

" ” 1 AlkamoonAlasod 1

--------------------------------------- T

Ranunculaceaei... . i

Seeds Khartoum local, marketI?

Salvadora persica L. Arakii Salvadoraceae i Leaves Kassala

11l

25

2.3.2. Sample analysisAn ICP-OES “Spectro Ciros Vision” system (SPECTRO Analytical Instruments GmbH

& Co. KG, Kleve, Germany) was used for Ca, Cr, Cu, Fe, K, Mg, Mn, Ni and Zn

determination in digested samples. Sample introduction was carried out using a

peristaltic pump equipped with an “antipulse-head” (SPETEC, Erding, Germany),

connected to a Mein hard nebulizer with a cyclon spray chamber. The measured spectral

element lines were Ca 317.933 nm, Cr 267.716 nm, Cu 324.754 nm, Fe 259.939 nm. Mg

279.079 nm, Mn 257.611 nm, Ni 231.604 nm, Zn 213.956 nm. The RF power was set to

1400 W, and the plasma gas was 13 L Ar/min, whereas the nebulizer gas was 0.6 L

Ar/min. For quality control, standard reference materials, rye grass (ERM-CD281) and

milk powder (ERM-BB150), were digested parallel to samples and analyzed together4

with the samples by ICP-OES.

2.4. INAA measurements

2.4.1. Sample preparation

Dried and homogenized plant samples, ranging between 1.0-0.2 g. were individually

packed in polyethylene irradiation vials. CRM 1547 (peach leaves) was used as certified

reference material for checking the consistency of the measurement technique.

2.4.2. Sample irradiations and measurements

The irradiations were performed at Morocco research reactor type Triga Mark II with1 z

maximum thermal flux of (1.944x10 n.cm s ). The details of the physical parameters that

determined the accuracy and precision of INAA are shown in Table (2.2).

The packed samples were individually irradiated for 25 s at a thermal flux of

-2-1

1 -26x10lzncm"z s' 1 in order to facilitate detection of short lived radionuclides. Samples

were counted immediately for 20 min.

Other batch of weighted samples was irradiated for 4 hours to detect long lived

radionuclides. After one month cooling interval, the gamma spectrometry system

equipped with a high purity germanium detector (HPGe) was used for sample activity

measurement. The measured activity of each sample was corrected for decay and

counted for one hour. Spectral analysis was performed with Ginie2000 software.

Calculations were performed using ko-IAEA program.

26

Table 2,2. Relevant Nuclear Data for determined radionuclides

Nuclideanalyzed

RadionuclideDetected

Half lifeT1/2

} .................... * ?

Gamma ray Branching ratioenergy (keV) (%)

l b M g 2/Mg 9.45 min 1014.44 28.00 j1 i11

i_____________________________________________________________i____________________________________________________________ ;

12.36 h 1524.60 18.08j

'i

^ C r 51Cr 27.7 d 320.080 10.08i ;

” Mn 5bMn 2.58 h 846.760 | 98.851!J

59Fe 44.5 d 1099.25 56.501 ;

"39Co 5.27 Y 1173.24 99.90ii!j

~ T J C u 12.70 h 1345.77 39.00iJ1

65Zn 243.9 d 1115.55 ! 50.701j1j

4SCa ^ C a 8.7 min 3084.40 91,70i

^ S r X5Sr 64.8 d 1065.00|

33.01

27

Chapter Three

Results and discussionOne of the most important issues regarding use of medicinal herbs is their trace element and

heavy metal contents. Adequate and necessary precautions should be taken into account while

supplementing the trace elements through such medicinal plants, in order to avoid other

complications of metal toxicity accompanied with the use of these plants.

Many analytical techniques are employed for quantifying trace elements in plant samples. The

principles of such technique were varied and each has its own consideration. Some of them apply

acid digestion for the samples prior analysis, as in the case of ICP-OES. while others requires

few sample preparations steps such as INAA. The selection was based on the reliability of the

results and the practical features. For example, a method could give acceptable results, but

requires sample preparation inadequate for the number of samples to be treated. Additionally, the

choice of method was also relied on the form of the material to be analyzed. For soil, sediment

and plant, INAA had the great advantage of not requiring samples to be dissolved. ICP-OES

requires dissolved samples, with non-negligible risk of pollution and lost. Some metal oxides

were incompletely dissolved, because all chemicals could not be used.

This study compares trace element concentrations (Ca, K, Zn, Mn. Mg, Sr, Fe. Cu. Co and Cr) in

14 Sudanese medical plants determined in parallel by INAA and ICP-OES to get information on

which technique is preferable at different matrices and element concentrations. The aim is also to

provide Information about measures to avoid technique-biased results.

3.1. Quality control

In order to evaluate the accuracy of the elements concentrations measured by the two employed

techniques, certified reference materials (CRM), namely ERM-CD 281 (rye grass) and ERM-BB

150 (milk powder) were used for quality control of ICP-OES measurements. While for INAA

technique CRM 1547 (peach leaves) certified reference material was used to quality control also.

The analysis of reference samples were used to specify the best method for each of the elements

of interest in our study as well to estimate the possible relative error of each technique. From the

tables 3.1 to 3.3 INAA showed an overestimation for the most of analyzed element with an

expectation of K, Ca and Mn that showed a negative relative error. A good agreement was

recognized for all listed elements when compared with their corresponding certified values, w ith

28

an exception for Cr which showed dramatically elevation will i 5 C ! ci l < X

Zn found to be in very low quantities . its measured vaw-, sho\x o

values with relative error of amount 4.4%.

On the other hand, ICP-OES underestimated in average across ail eicmcm-

material or - 2.3% in milk powder. The deviations of specific element1: -- .n j j

4,9%. Ideally, both techniques expected to provide the same result- and m em

The slight underestimation of ICP-OES measurements is characieri/xd '

findings: the SD bars still overlap with certified mean values \ r V - . * ; V•• • : d i iV.i.!v

certification, indicating that deviations from the target values are wnau 5 : i V !

more pronounced in the rye grass CRM. which is to c o n ta in

metals as oxides or silicates than the milk powder sample Conwixcd.

< ..n o n : - ;I i r ! I ^ %

. A; ac

concentrations of the most studied elements using 1NAA could he related w i i At i i

matrix, as well as some problems at low element concentration is delected.

In conclusion, the elemental levels obtained for employed reference material s

different techniques were in agreement with their certified values, suggesting

non-destructive IN A A and destructive ICP-OES for plant elemental anaf\ S ! x

Table 3.1 Elemental concentrat ion (Mean ± SD mg/kg) o f SRM 1 547 i peac % u I

1 Element ! Measured value !mg/kg ;

Certified value mg/kg1 • 1

Ki!1

23028 i|1i

24300

Mgj

4403 !•l!i

4320

i Ca.

_____ j13594 1

.i:[

15600

Fe 239 11!|2 i 8

f .... ■ ■ i i ,Zn

|_ . _ __ 118.68

,i'1[7.9

Mn 91.87 i 98

S b*" i

\

% J<

\

Table 3.2 Elemental concentration (Mean ± SD mg/kg) of reference ERM-CD 281 (rye grass) using ICP-OES

Element Measured value mg/kg

Certified value mg/kg

Relative Error %1

1

|

B 5.5± 0.2 5.5± 0.5 0.011

1

Cr 22.7± 0.4 24.8± 1.3 -8.5 j1

1

1

Cu 9.7 ±0.2 10.2± 0.5

1 | i

i kO

Mn 77.5 ±1.1 82± 4 -5.5 !1

\1

lr

Ni 13.9 ±0.3 15.2± 0.6 -8.61

1

Zn 28.3± 0.3 30.5± 1.1 -7.2!

1i

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ J

Table 3.3 ICP-OES measurement (Mean ±SD mg/kg) of reference material milk powder (ERM-BB150)

Element Measured value mg/kg

Certified value mg/kg

Relative Error % ■

!!Ca 13760±150 13800±800 -0.3

i

K 16590±200 17000±100 -2.4!

Mg 1240±30 1260±190 -1.6 !: |

Na 4140±10 4180±190 -0.9 1J

Cu 0.97±0.02 1.08±0.06 -10.1

Fe 4.54±0.06 4.6±0.5 -1.4

Mn 0.28±0.01 0.29±0.02 -1.811

Zn 45.14±0.61 44.8±2 0.811|1___________________ 1

h

30

INAA SRM 1547

-20 - lO O lO 20 30 40 50 GO 2 0Relative Error %

Figure3.1 INAA SRM 1547 relative error %

-1 0

Figure 3.2 ICP-OES ERM-CD 281 relative error %

ICP-OES ERIV1-BB 150

-12 -lO -S -6 - 4 - 2 0 2

Relative Error %

Figure 3.3 ICP-OES ERM-BB 150 relative error %

31

5.2. Comparison of INAA and ICP-OES results

j en e ra l lv . the d i f f e r e n c e in e l e m e n t s c o n te n t o f the m e d ic in a l p lan ts is m o s t i \ . iscuix 'dw .

l i f f e ren c es in the p re fe re n t i a l a b s o r p t io n o f the p lan ts , in ad d i t io n the m in e ra l c o m p o s i t i o r

;oil in w h ic h the p la n t s are g r o w n . O th e r fac to rs tha t re la te to the v a r i a t io n s m e o n c e n t r a t

n c lu d e use o f fer t i l izers , i r r iga t ion w a te r an d the c l im a t i c c o n d i t io n s .

\ c o m p a r i s o n b e t w e e n th e t w o d i f f e re n t ana ly t ica l m e t h o d s w a s c o n d u c t e d to d e t e n m n c u

l i f fe rence in th e d e t e r m i n e d c o n c e n t r a t i o n s o f th e s e e l e m e n t s can be o b s e r v e d . A s can nc

i ' ■■ V

f • t

I V

ion a im

1 i’ V * •1 \ C i 1

sl l 1;

ab le s (3 .4) an d (3 .5) . all e l e m e n t s in the s a m p l e s w e r e d e te c te d by I C P - O f S . w h i le the results

rom I N A A s h o w e d tha t the t e c h n i q u e w a s not ab le to m e a s u r e s o m e d e m e n t s , such as ( a N t

md C r in th e s a m e s a m p l e s w h ic h the i r c o n c e n t r a t i o n s are p robab lv be low the d e te c t io n m m :

::ach e m p l o y e d t e c h n i q u e has its o w n c o n s id e r a t i o n s and a d i f f e re n t approach. , i lo w e v e r . in ordci

o rely on bo th t e c h n i q u e s the re is e x p e c ta t io n o f s o m e c o r r e l a t io n s b e tw e e n t h e r e s u l t s

tehieve th is p u rp o s e , a c o m p a r i s o n b e tw e e n ten e l e m e n t s ( d a . k . I e. \ i n . M g. Sr. / m l u. ( A

md Cr) has been c o n d u c t e d . T h e se lec t io n o f th e s e e l e m e n t s w a s d e c i d e d a c c o r d in g to th

n te r se c t io n o f e l e m e n t s d e t e r m i n e d by bo th t e c h n iq u e s .

ITie c o r r e l a t i o n s b e t w e e n the resu l ts o b ta in e d for the a b o v e m e n t i o n e d e l e m e n t s w e re e x a m i n e e

nd the o b t a in e d c o r r e l a t i o n c o e f f i c ie n t ( R d and s lo p e v a lu e s w e re d i s c u s s e d ! rom fiiiutxw (-i4

97). s tromz c o r r e la t io n w a s o b s e r v e d for all e l e m e n t s w ith h iuh c o n c e n t r a t i o n s such as (. a (R

>.92 1). k ( R “ 0 .9 0 1 ) an d M n ( R “ ^ 0 .975 ) . A l th o u g h Z n d e m e n t ton nd m a co n -d d c rah le l o w

[mounts . g o o d a g r e e m e n t b e tw e e n the t w o d i f fe ren t t e c h n i q u e s w as n o t i c e d w i th R (). o'

implying the ab i l i ty o f bo th t e c h n i q u e s to d e tec t th is e l e m e n t e f fec t ive ! ;v even ai \erv i raee

imounts

vlg e l e m e n t s h o w e d s lo p e va lue c lo sed to o n e (0 .9 0 4 ) w h i l e it is c o r r e la t io n c o e f h c i c m 1C

) .648,T h is c o n t r a d i c t i o n can be jus t i f ied bv the ab i l i ty o f bo th t e c h n i q u e s to m e a s u r e * ]

dem ent w h e n its c o n c e n t r a t i o n s w e re below 2 0 0 0 irm/ka . H o w e v e r , a b o v e t ins c o n c e n t r a t io n a

i iscrepancv b e t w e e n the resu l t s o b t a in e d bv both t e c h n i q u e s co u ld be o b s e r v e d with ratio w

ibout 1.4. as p r e s e n t e d in fm u re 3.8. f r o m the resu l ts o f r e f e r e n c e m a te r i a l s ( f a b l e s

N A A s h o w e d o v e r e s t i m a t i o n o f c o n c e n t r a t i o n o f th is e l e m e n . w h i l e K IM )l S unde res t im a te^

ts c o n c e n t r a t io n w i th th e s a m e a b s o lu te a m o u n t for IN A A .

32

Similar to Mg and Co was found to be significantly affected when it is concentration getting

lower than 0.5mg/kg (figure 3.8, 3.10). Moreover; 1NAA was not able to detect its

concentrations in some studied plants.

Regarding Fe (figure 3.9), very strong correlation (R2 = 0.992) was reported for this element

however the value of the slope was less than one (0.729).This indicating the variation between

the results obtained by the two implemented techniques for the same samples.

In this study, most values of Cu and Sr were not detected by INAA for the most studied plants

(below 3 mg/kg for Cu and 78 mg/kg for Sr), for this reason the correlation for both elements

was not conducted.

33

Table 3.4 Element concentration (Mean ^SD mg/kg) in Sudanese medicmai i i

Plant Ca Kj Zn Mn

1l

N E1

mg/kg mg/kg m g/kg mg/kg^ r ' ^ »-* ; mg/kgj 1 1 i w l\ W •, *15 , : ^< W.. s

Acacia nilotica ( L . ) 6955±5 12080+ 10.28+1 i 3.24± ; 649.3::: Z0 : r

•• • 1. .b \

-A ** V'\ ■ ; —w,,

Wild. ! \ Dei. 7,9 >

1|

1.61 ! S 1i i l f

1.2 1 44.7i1 A ^! e .. /

Acacia Senegal (L.) : 8039+2 ; 7872 ; i ! N D ND 1282±3 7S OS r\ ‘ * r

' N " *j \ ;Wild

1

.9• 1 i / -i ■> ij ; 1 1

s "S. N, j V.

Balanites aegyptiaca 751.4+ | 19100: i1 i N D ND 433.4+ ND^ /’Hi

sM ' \ . ;K ; V’•fc .

L.) Del 6.71

i . . .

1.4 :11

1 1.4 '• 4-

Cajanus cajan (L.)+ • s ! /48.2± ; 13990± 31.07+6 ! 3.57± 1026±4 ND \ i * i

; > *. N\Vlillsp 5 2•w* *

lj . . ..

! 1 - 1 s1

i j

.4 16 iV

Capsicum frutescens ■ 874.7±| 1 27430± ;| j 19.07+2 14.95+ 1795*4 ND 2 ! 8 4 ~ i J ' * *■ h_ ;T

1

- 5.8f1 ■- I ! I m ; 0.8 c ">

* r

\ s% >1 . J— \ ’

Citrullus colocynthis 602.4±1

5624+1 25.72+1 15.37± ; 2043+6 ND — , fc i ' ! ) ! -■ : i- i j > i : ^L

/.Schrad. ! 1 0 .6! •; .

i

6.5 28.9

Cucurbita maxima ' 371 .9± ! 7772±l I 73,03±3 16.23+ ' 1901 =*=2 \ 1) O ■>. ^ - " E'.S; “S , . 1

\ / \ [N. — f

w p 6.9 ! s1 11 1L | .6 N

J .8—

w ■' \ *"• » N. r

■'ymbopogon 1263+7! 6354—1 1 1.66=2=1 145.5+ 975.8+ N D 28 VS-. \D x -V .P

Aoximus Stapf. ..5• Si j ■ i1 i

| i

/ 4.8 10.5 N -v S - ■ \

- -"K

-oeniculum vulgare ] 3670± 26440± 27.92±8 83.5+1 5419±6 134.8- 28S7 -:.3 \ ! ) ' : h

’Mill 5.1 ! 1.6 !1 I

_ L .. . i

ip.r M 0.1 - O « it _ i, i

juiera senegalensis 13360± ! 9 0 8 2 + I !I ! 26.85^8 556.4+ 2 5 7 i±S N D :■ 8 . 5 - \ !) +M T ■

T.Gmel. JOi !1 S '1 — i ; 1 i |f |

.8 b

iapiophyllum tuber- 6586±4 : 14270: i 8.57+25 ND 1022+1 \ i a \D \ i

alarum ! 1.6 j! |

.9 0 . 5 18.ii

.awsonia. inermis L 10880+J

: ND !1 ' i li i: i

13.93 41.71 +i

/

2913+31

1 /

1

1 /4_a-5..6

20SNr:; 0,U

V l\ \} >

■

Cgella sativa L. ; 6 7 1 2 : 5 ; 8921+1 j 45.6+6. , 39.2+1 3806+5 ND K) 18-5 ( 'l ’ 'A . % / 's .

!i1ji

1 1 .7 ■D 5.11

|A - ■ V- j N

alvadora persica L. 8018±5j 13740+ ' ND ND : 679 .2=t 200+ iI \[) N[ •\ rV ; ; - *

.6i 1.6 1 1.7i

34

Table 3.5 Element concentration (Mean±SD mg/kg) in Sudanese medicinal plants obtained by 1CP-OES

Planti

Camg/kg

Kmg/kg

Znmg/kg

Mnmg/kg

Mg Sr Fe Cu Co Cr mg/kg 1 mg/kg j mg/kg ; mg/kg mg/kg : mg k

Acacia nilotica (L.) Willd. Ex Del.

6540±311

12200± 353

11 ±2. 0

10i 0.c6

459±2J9

77.3±5 250±9.0 ; 3±0.2 i 0.6±0. 0.6=4i ,i rAcacia Senegal (L.) Willd.

7595±79

7440±721

0.2±0.1

2±0.01

1235± | 8I.6±7 36 |

10± 1.0 1 1 ±0,1 i 0.6±(.) ' 0.6±( 1 , !

Balanites aegyptiaca (L.) Del.

850±9 16300±282

3±0.1 1.3±0. 1

519±9 .2

6.8±1 | 12±0.9 ; 1.1 ±0.1 : 0.6±0. i 0.53=1 1

Cajanus cajan(L)Millsp,

640±24

14900± 141

33±0.4

14±0.1

1040±0.01

4.7±0.81 35±1.0 : 12±0.4 I 0.5x0. ! 0.6±(1 ’ 1 11 -f

i

Capsicum frutescens L.

716±7 22300±141

17±0. 2

12±0.2

1485±35

5.3±0.911F

i _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

174±2 I 10±0.1 ! 0.5±0. | 0.5±(1 i '? ; i !1 ... f

Citrullus colocynthis (L) Schrad

505±12

4960±3a

28±4.6

15±0. 8

2070± j 2.6±0.1 1 28 !

46±5.0 | "±0.5 i 0.5±0. I 0.6=C’ 1] ! >1 ....... .. i 1 _i__ ' __Cucurbita maxima L 531±1

06860±1

1374±1.

J32±0.

13750±

423.1 ±0.1 ; I73±I3 ! 12±0. 1 ! 0.6±0.

1 il ■ 1 1 i1 i i

0.6=C

CymbopogonproximusStapf.

1170± 0.001

5950±0.001

22±5 209±10

880±12

1.1 ±0.9 \ 189-10 : 1-0.1 0.6±0.1 I: : 1l . ... ... 1 .. .. ._

0.6-tTIlFoeniculum vulgare P. Mill.

11600±112

23700±424

25±1 66±3.4

3750±84

47±1 1 2105±3I 4

11 ±0.5 : 1.1 ±0. 1 4±0.(1\A• I

Guiera senegalensisJ.F.Gmel,

10100±56

8720±85

26±2 518±3A

1995±46

47.4±2 i 534±5 ! 6±0.5 i 2.7±0.1r \\ : 1 11. 2=(

\.JtHaplophylumtuberculata

6870±261

14400±282

1 1±1 13±0. 4

763±3J

6.2±0.9 ! 82±3 i 3±0.I ! 0.6±0. ! 0.7±tf ;' 1 ; * i ; l i

Lawsonia inermis L. 13800±636

6330±197

12.5± 0.5

52±2 4070±19

269±7 259±6 ; 4±0.2 i 0.6±0. J 0.6±Ci : :. .. i . . .... i

Nigella sativa L„ 6240±23

8600±15

46±2 34±0.6

3130± 56

28.8±2 1J

695±41Ir

8±0.2 : 0.5±0. i 2=0.(!

Salvadora persica L.ii1

8350±41

13500±212

8±0.6 4±0.2 614±2J

268±4 1J

25=0.6 | 4±0.2 1 0.6--0 | 0.6±C! ij 1 M*

35

A- •

y = 1.009x

R2 = 0.921

l

)i\\*4441

i44

ii

1S

14

}4

j12

s

i<11cJ4i49

INAA........ .. .11| 111 MM1

fJ

Figure 3.4 Plant calcium contents measured by INAA and ICP-OES

30

25

20LOLU9 15O.U

10

5

0

y = 0.901x

R2 = 0.964

............ d i ^ i H i ^ i i > < i i | i i ‘ r i T i T i v d r i

Figure 3.5 Plant potassium contents measured by INAA and ICP-OES

Figure 3.6 Plant zinc contents measured by INAA and ICP-OES

3 6

Figure 3.7 Plant manganese contents measured by ! N A A and ICP-OES

6000

5000

COLXJ4000

Oia.u

3000

2000

1000

0

Mg y = 0.904x R2 = 0.648

0 1000 2000 3000INAA

4000 5000 6000■ ---------------------------------------------------------------- — . . . ^ ........pj(i p tn ~ T r»‘ y i t H V H M S k M U U i e b

Figure 3.8 Plant Manganese contents measured by [NAA and ICP-OES

2500

<

v = 0.729x R2 = 0.992

‘ m l J i l ^ J w i l i i p p i U i i i r i I m l i d i n t i l i t i l i *

3500

Figure 3.9 Plant iron contents measured by INAA and ICP-OES

37

cn

y = 0.994x

R 2 = 0 805I|

II

L

j

Figure 3.10 Plant cobalt contents measured by INAA and ICP-OBS

5

4

Q.U

3

2

1

t

y = 0.183xR2 = 0.456

♦

Figure 3.11 Plant chromium contents measured by INAA and ICP-OFS

3.3. ConclusionsBased on the results of this comparative study on elemental analysis of medicinal plants using

INAA and ICP-OES, the most concluding remarks are that:

• INAA is equally competitive method for the measurements of calcium, potassium, iron,

manganese, magnesium and zinc in medicinal plants, besides ICP-OES.

• Non-destructive nature of the INAA might give it the advantage of handling with ease

and less time consuming over ICP-OES technique.

• ICP-OES seems to be the superior technique over INAA when measuring chromium,

nickel and copper in the medicinal plants.

38

Chapter Four

ReferencesAhmed E, Nour B, Mohammed Y and Khalid H (2010) Antiplasmodial A c t iv i ty o f S o m e

Medicinal Plants Used in Sudanese Folk-medicine, Environmental Health Insights: 4:1-6

Ballatori N (2002) Transport of toxic Metals by Molecular Mimicry .Environ Health Persp;

110:689-694

Be M, Chiste V, Dulie C. Browne E, Chechev V, Kuzmenko N. Helmer R. Nichols A.

Schonfeld E and Dersch R (2004) Tables of radionuclides. Reproduction service. Boulevard

Verd-de-Saint-Julien 92190 Meudon; ISBN 92-822-2206-3: Voll

Boss C and Fredeen K (1997) Concepts. Instrumentation and Techniques in Inductive!}

Coupled Plasma Optical Emission Spectrometry,2th Edition, Perkin Elmer, Pg 36-71

De Corte F (1987) The ^-standardization method, a move to the optimization of neutron

Activation analysis. PhD Thesis, University of Gent

De Corte F, Simonits A, De Wilspelaere A and Hoste J (1987) Accuracy and applicability of

the ko -standardization method. J Radioanal Nucl Chem; 1 13:145-154

Debrah S, Ayivor J, Denutsui D, Kwofie B, Forson A, and Nuviadenu C (201 1) Elemental

evaluation of some herbal plants used in Ghana using INAA.Der Pharma Chemica; 3 (5):

202-207

Downer N (2008) Method Development for the Digestion and Analysis of four Common

Sedimentary Lithologies using ICP-OES and ICP-MS, master thesis, Universit} of

Johannesburg, South Africa

Dzoyem .1, Tshikalange E and Kuete V (2013) Medicinal Plant Research in Africa Medicinal

Plants Market and Industry in Africa. Publication Book http://www.turner.ukzn.ac.za

Ebrahim A, Eltayeb M , Khalid H, Mohammed H, Abdalla W. Grill P and Michaike B (2012)

Study on selected trace elements and heavy metals in some popular medicinal plants from

Sudan Journal of Natural Medicines; 66:671-679

El-Taher A and Alharbi A (2013) Elemental analysis of natural quartz from Urn Higlig. Red

Sea Aea, Egypt by instrumental neutron activation analysis. Applied Radiation and Isotopes

82; 67-71

39

Eltohami M (1997) Medicinal & Aromatic Plants in Sudan. Medicinal. culinar\ and aromatic

plants in the near east available on line http://ww\v .fao.org/docrep/x 5402e/x 5402el6.htm

Fraga G (2005) Relevance, essentiality and toxicity of trace elements in human health

Molecular Aspects of Medicine; 26: 235-244

Funtua I, Oladipo M, Njinga R. Johan S, Yusuf I and Ahmed Y (2012) Evaluation tor

Accuracy and Application of Instrumental Neutron Activation Analysis of Geological

Materials on Nigeria Nuclear Research Reactor. International Journal of Applied Science and

Technology; 2: 286-292

Ghosh S, Prasanna V. Sowjanya B, Srivani P, Alagaraja M and Banji D (2013) inductive!}

Coupled Plasma -Optical Emission Spectroscopy: A Review. Asian Journal Pharm Ana:

3(1): 24-33

Griffiths W (2007) Review Article: The Genetic Basis of Hemochromatosis. Aliment

Pharamocacol Ther 26:331-34

Flaciyakupoglu S, Esen A and Erenturk S (2014) Experimental parameters optimization of

instrumental neutron activation analysis in order to determine selected elements in some

industrial soils in Turkey, Radiation Physics and Chemistry. Journal of radiation physics and

chemistrv; 3:34-54

Hamidatou L, Slamene H, Akhal T and Zouranen B (2013) Concepts, Instrumentation and

Techniques of Neutron Activation Analysis .http://dx.doi.org/10.5772/53686

http://www.lenntech.com/periodic/elements/sr.htm

Hussain J, Ur Rehman N, Khan A, Ali L, Al-Harrasi A, Shinwari Z. K, Hussain H. and Rizvi

T (2013) Proximate Based Comparative Assessment of Five Medicinal Plants to Meet the

Challenges of Malnutrition. European Journal of Medicinal Plants; 3(3): 444-453

IAEA-TECDOC-1121 (1999) Industrial and environmental applications of nuclear analytical

techniques, Report of a work shop held in Vienna, 7-11 September 1998

Khalid H, Abdalla W, Abdelgadir H, Opatz T and Efferth T (2012) Gems from traditional

north-African medicine: medicinal and aromatic plants from Sudan. Nat Prod. Bioprospect:

2:92-103

Kharfi F (2013) Imaging and Radioanalytical Techniques in Interdisciplinary Research -

Fundamentals and Cutting Edge Applications, Publishing Process Manager Iva Simcic. ISBN

978-953-51-1033-0

40

Kim I. Lee K , Hwang E, Min H and Yim Y (2013) Accurate measurement of bromine

contents in plastic samples by instrumental neutron activation analysis. Analytiea

Chimica Acta; 769: 22-29

Lokhande R, Singare P, Andhele M and Acharya R (2010) Study of some Indian medicinal

plants by application of INAA and AAS techniques. Natural Science; 2: 26-32

Makrides M and Adelaide S.A (2010) Mother and Child Nutrition, Annales Nestle (English

Ed) Vol. 68, No. 1, ISBN: 978- 3- 8055- 9507- 0.

Marie Kubesova (2012) ko standardization in neutron activation analysis at LVR-15 reactorV ______

in Rez, PhD thesis, Czech Technical University in Prague, Faculty of Nuclear Sciences and

Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation

Marques R, Prudencio M, Rocha F, Pinto M, Silva M, Da Silva, E (2012) REE and other

trace and major elements in the topsoil layer of Santiago Island, Cape Verde. Journal of

African Earth Sciences: 64:20-JO

Mossad S , Macknin M , Medendorp S and Mason P (1996) Zinc gluconate lozenges for

treating the common cold, Annals Internal Medicine; 125(2): 81-88

Mukhtar M, Arshad M, Ahmad M, Pomerantz R, Wigdahl B and Parveen Z (2008)

Antiviral potentials of medicinal plants. .1 Virus Research; 131 (2): 111-120.

Mustra CO, Freitas M C, Almeida S M (2003) Neutron flux and associated k parameters in

the RPI after the last configuration change, Journal of Radioanalytical and Nuclear

Chemistry; 257: 539-543

Niamat R, Khan M, Khan K , Ahmed M, Ali B, Mazari P, Mustafa M, and Ahmed FI (2012)

Element Content of Some Ethnomedicinal Ziziphus Linn Species Using Atomic Absorption

Spectroscopy Technique. Journal of Applied Pharmaceutical Science; 2 (03): 96-100

Raju G , Sarita P, Rao J, Rao K and Reddy S (2013) Correlation of trace elemental content in

selected anticancer medicinal plants with their curative ability using particle induced x-ray

emission (PIXE). Journal of Medicinal Plants Research; 7: 1082-1086

Raman B and Pednekar P (2013) Multi-element determination methanolic soxhlet leaf extract

of Semecarpus Anacardium (Linn.f) by ICP-AES technique. Asian Journal of Pharmaceutical

and Clinical Research; 6(3): 132-137

Saraf A and Samant A (2013) Evaluation of some minerals and trace elements in

Achyranthes aspera Linn .International Journal of Pharma Sciences; 3: 229-233

41

Selvaraju R, Thiruppathi G, Raman R.G and Dhakshanamoorthv D (2011) Estimation of

essential and trace elements in the medicinal plant Tribulus Terrestris by ICP-OES and

Flame photometric techniques. Romanian journal of biology ; 56(1): 65-75

Shaddad I (1995) (n, p) and (n, a) reactions cross-sections measurement and systematic

around 14 MeV neutron energy.PhD thesis in physics university of Khartoum. Sudan

Shirin K, Imad S, Shafiq S and Fatima K (2009) Determination of major and trace elements in

the indigenous medicinal plant Withania somnifera and their possible correlation with

therapeutic activity .Journal of Saudi Chemical Society; 14:97-

Verma H.R. (2007) Atomic and Nuclear Analytical Methods, ISBN-10 3-540-30277-8

Springer Berlin Eleidelberg, New York: 267-268

Wada O (2004) .What are trace elements? Their deficiency and excess states. Japan Medical

Association Journal ;47(8): 351-358

Zetic V, Tomas V, Grba S, Lutilsky L, and Kozlek D (2001) Chromium uptake by

Saccharomyces cerevisiae and isolation of glucose tolerance factor from yeast biomass.

Journal of Biosci; 26(2): 217-223

100

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