Titrimetric and Spectrophotometric Methods for the …eprints.uni-mysore.ac.in/16569/1/697651.pdf · cobalt content in the complex after extraction in 0.1M ... in sulphuric acid medium

Hindawi Publishing CorporationInternational Journal of Analytical ChemistryVolume 2013 Article ID 697651 9 pageshttpdxdoiorg1011552013697651

Research ArticleTitrimetric and Spectrophotometric Methods for the Assay ofKetotifen Using Cerium(IV) and Two Reagents

Madihalli Srinivas Raghu Kanakapura BasavaiahKudige Nagaraj Prashanth and Kanakapura Basavaiah Vinay

Department of Chemistry University of Mysore Manasagangotri Mysore Karnataka 570006 India

Correspondence should be addressed to Kanakapura Basavaiah kanakapurabasavaiahgmailcom

Received 22 February 2013 Revised 15 May 2013 Accepted 29 May 2013

Academic Editor Jan Ake Jonsson

Copyright copy 2013 Madihalli Srinivas Raghu et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

One titrimetric and two spectrophotometric methods are described for the determination of ketotifen fumarate (KTF) in bulk drugand in tablets using cerium(IV) as the oxidimetric agent In titrimetry (method A) the drug was treated with a measured excessof cerium(IV) in H

2SO4medium and after a standing time of 10 min the surplus oxidant was determined by back titration with

iron(II)The spectrophotometric procedures involve addition of a known excess of cerium(IV) to KTF in acid medium followed bythe determination of unreacted oxidant by reacting with either p-dimethyl amino benzaldehyde andmeasuring the resulting colourat 460 nm (method B) or o-dianisidine and subsequent measurement of the absorbance of coloured product at 470 nm (method C)Titrimetric assay is based on a 1 2 reaction stoichiometry between KTF and cerium(IV) and the method is applicable over 2ndash18mgrange In spectrophotometry regression analysis of Beerrsquos law plots showed a good correlation in 04ndash80 and 04ndash100 gmLminus1 KTFranges formethod B andmethod C respectively and the correspondingmolar absorptivity coefficients are calculated to be 40times104and 37 times 104 Lmolminus1 cmminus1

1 Introduction

Ketotifen fumarate (KTF) (Figure 1) chemically knownas 49-dihydro-4-(1-methyl-4-piperidinylidene)-10H-benzo[4 5]cyclohepta-[12-b] thiophen-10-one which be-longs to the group of cyclohepta thiophenones is anantiallergic drug with stabilizing action on mast cellsanalogous to that of sodium cromoglycate and anti-H

1effect

[1] Ketotifen is given orally as fumarate in the prophylacticmanagement of asthma and is used in the treatment ofallergic conditions such as rhinitis and conjunctivitis [2]Ketotifen is a nonbronchodilator antiallergic properties andhas a specific anti-H

1effect [3]

The drug is official in British Pharmacopoeia [4] whichdescribes a potentiometric titration with perchloric acidin acetic anhydride-acetic acid medium The therapeuticimportance of the drug has prompted the development ofa variety of techniques for its assay in pharmaceuticals andbody fluids In pharmaceuticals it is quantified by high per-formance liquid chromatography [4ndash10] high performance

thin layer chromatography [11] liquid chromatography withtandem mass spectrometry [12] capillary electrophoresis[13] spectrofluorimetry [14] direct differential pulse polaro-graphic and adsorptive-stripping voltammetry [15] and UVspectrophotometry [16 17] Potentiometric titrationmethodsemploying polymeric membrane sensors were also devel-oped where the method involved potentiometric titration ofthe drug with sodium tetraphenylborate [18 19] Determina-tion ofKTFhas also been carried out based on chemilumines-cence [20ndash22] Coulometric titration of KTF in pure drug andin tablet forms using biamperometric end-point detectionwas developed by Ciesilski et al [23]

To the best of our knowledge no visual titrimetricmethod has ever been reported for KTF Visual titrimetry andvisible spectrophotometry may serve as a useful alternativesto many of the aforesaid sophisticated techniques becauseof their cost-effectiveness ease of operation sensitivity fairaccuracy precision and wide applicability

Several visible spectrophotometric methods based oncolour reactions involving the amino or thiophene of the

2 International Journal of Analytical Chemistry

O

S

N

HO OHO

O

CH3

Figure 1 Structure of KTF

ketotifen molecule can be found in the literature El-Kousyand Bebawy [24] have developed three methods for theassay of KTF in bulk drug and in tablets the first methodwas based on extraction of drug-cobalt thiocyanate ternarycomplex with methylene chloride and estimation by indirectatomic absorption method via the determination of thecobalt content in the complex after extraction in 01Mhydrochloric acid at 2407 nm The second method is basedon the formation of orange red ion pair by the reaction ofKTF and molybdenum thiocyanate with absorption maximaat 4695 nm in dichloromethane The third method was acharge transfer reaction between drug and 23-dichloro-56-dicyano-p-benzoquinone in acetonitrile medium Sastryand Naidu [25] have determined the drug in tablets andsyrup based on the reduction of Folin-Ciocalteau reagentto a blue coloured chromogen measurable at 720 nm inthe same article KTF was treated with a measured excessof N-bromosuccinimide (NBS) the unreacted oxidant wasreacted with celestine blue and the change in absorbancewas measured at 540 nmThe third method was based on theformation of colored species by the coupling of the diazotizedsulphanilamide and absorbance of the colored species wasmeasured at 520 nm

There are three reports on the use of ion-pair reaction forthe assay of KTF An extractive spectrophotometric proce-dure was based ion-pair reaction using Azocarmine G as ion-pair reagent at pH 15 The ion-pair complex extracted intoCHCl

3was measured at 540 nm [25] Sane et al [26] have

described four extractive spectrophotometric proceduresbased on this reaction using bromophenol blue bromoth-ymol green bromothymol blue and bromocresol purpleas ion-pair reagents in acidic medium The drug has alsobeen determined spectrophotometrically based on ion-paircomplex formation with bromocresol green [27] at pH 30followed by extraction into chloroform and measurement at423 nm Beerrsquos law is obeyed over the concentration range515ndash6191120583gmLminus1 KTFThe charge-transfer reaction of KTFwith picric acid was developed by Vachek [28] The methodinvolves extraction of the picric acid-drug complex intochloroform and measurement of the extract at 405 nm

The reported spectrophotometric methods suffer fromsome other disadvantage such as narrow linear range poorsensitivity dependence on critical experimental variablestedious and time-consuming extraction steps heating stepandor use of expensive reagent or large amounts of organicsolvents as indicated in Table 1

From the foregoing paragraphs it is clear that cerium(IV)despite its strong oxidizing power versatility and high stabil-ity in solution has not been applied for the assay of ketotifenThis paper describes for the first time the application ofacidic cerium(IV) to the titrimetric and spectrophotometricdetermination of KTF using p-dimethyl amino benzaldehydeand o-dianisidine as chromogenic agents cerium(IV) hasearlier been widely applied for the assay of a variety ofpharmaceuticals [29ndash33]

2 Experimental

21 Apparatus A Systronics model 106 digital spectropho-tometer (Systronics Ahmedabad Gujarat India) with 1 cmpath length matched quartz cells was used to record theabsorbance values

22 Materials All chemicals used were of analytical reagentgrade Double distilled water was used throughout the inves-tigation Pharmaceutical grade KTF (9978 percent pure) wasprocured from Cipla India Ltd Mumbai India as a giftand used as received Asthafen-1 (Torrent pharmaceuticalsSikkim India) and Ketasma-1 (Sun pharmaceuticals SikkimIndia) tablets were purchased from local commercial market

23 Reagents and Chemicals Cerium(IV) Sulphate(0005M) An approximately 001M solution was preparedby dissolving about 252 g of the chemical Ce(SO

4)2sdot4H2O

(Loba Chemie Pvt Ltd Mumbai India) in 05M sulphuricacid with the aid of heat and diluting to 250mLwith the sameacid and standardized using standard ferrous ammoniumsulphate solution (FAS) [34] It was used for titrimetric workand diluted to obtain working concentrations of 300 and100 120583gmLminus1 cerium(IV) for spectrophotometric methods Band C respectively with the same solvent

Perchloric Acid (4M) Perchloric acid (4M) was prepared bydiluting appropriate volume of commercially available acid(70 Merck Mumbai India) with water

Sulphuric Acid (5M) A 5M sulphuric acid was prepared byappropriate dilution of concentrated acid (98 Sp gr 184Merck Mumbai India) with water and used in bothmethodsB and C

Ferroin Indicator It was prepared by dissolving 0742 g of 110-phenanthroline monohydrate in 50mL of 0025M ferroussulphate solution (0348 g of ferrous sulphate heptahydrate in50mL water)

119901-Dimethylamino Benzaldehyde (119901-DMAB) (05) An accu-rately weighed 05 g of119901-DMAB (MerckMumbai India) wastransferred to a 100mL volumetric flask and dissolved in 4MHClO

4and the volume was made up to the mark with the

same solvent

119900-Dianisidine (ODS) (005) An accurately weighed 50mgof 119900-dianisidine (Merck Mumbai India) was transferred to

International Journal of Analytical Chemistry 3

Table 1 Comparison of the performance characteristics of the proposed methods with the existing visible spectrophotometric methods

Serialnumber Reagent(s) used Methodology 120582max

(nm)

Linear range(120583gmL)

(120576 = Lmolcm)Remarks Reference

1(a) Molybdenumthiocyanate(b) DDQ

Methylene chloride extractableion-pair complex measured

4695588

5ndash37510ndash80

Employs unstableoxidant narrow linearrange

[24]

2

(a) F-C reagent(b) NBS-celestine blue(c) Sulphanilamide(d) Azocarmine G

Measurement of the absorbance ofblue colored chromogenUnreacted NBS measured usingcelestine blue in acid mediumMeasurement of pink coloredcoupled product of drug withdiazotized sulphanilamide withdrugChloroform extractable 1 1 ion-paircomplex was measured

720540520540

4ndash282ndash121ndash1025ndash25

Multistep unstableoxidant strict pHcontrol and tediousextraction procedure

[25]

3

(a) Bromophenol blue(b) Bromothymol green(c) Bromothymol blue(d) Bromocresol purple

Chloroform extractable 1 1 ion-paircomplex was measured mdash 0

Required close pHcontrol and narrowlinear range andinvolved tedious timeconsuming extractionsteps

[26]

4 Bromocresol green Chloroform extractable 1 1 ion-paircomplex was measured 423 515ndash6191


[27]

5 Ce(IV)-119901-DMAB Oxidation form of 119901-DMABmeasuredOxidation form of 119900-dianisidinemeasured

460 04ndash80(40 times 104) Simple highly sensitive

extraction free and useof stable cerium(IV)solution

Thiswork

Ce(IV)-119900-dianisidine 470 04ndash10(37 times 104)

a 100mL volumetric flask and dissolved in ethanol and thevolume was made up to the mark with the same solvent

Standard KTF Solution A stock standard solution equivalentto 20mgmLminus1 KTF was prepared by dissolving 200mg ofpure drug with water in a 100mL calibrated flask Thissolution was used in the titrimetric work and a working con-centration of 20120583gmLminus1 was prepared by stepwise dilutionwith the same acid and used in method C For method B200120583gmLminus1 KTF solution was prepared separately by dis-solving accurately weighed 20mg of pure drug in 4MHClO

4

and diluting to volume with the same solvent in a 100mLstandard flask and the resulting solution (200120583gmLminus1) wasdiluted to 20120583gmLminus1 with 4MHClO

4and used for assay

3 Assay Procedures

31 Titrimetry (Method A) A 10mL aliquot of the KTFsolution containing 2ndash18mg of KTF was transferred into a100mL conical flask To this 10mL of 0005M cerium(IV)sulphate was added using a pipette and the contents weremixed well and the flask set aside for 10min Finally theunreacted oxidant was titrated with 0005M FAS solution

using one drop of ferroin indicator Simultaneously a blanktitration was performed and the amount of the drug inthe measured aliquot was calculated from the amount ofcerium(IV) reacted

The amount of KTF in the aliquot was calculated usingthe formula

Amount (mg) =(119861 minus 119878) times119872

119908times 119862

119899 (1)

where 119861 = volume of FAS consumed in the blank titrationmL 119878 = volume of FAS consumed in the sample titrationmL 119872

119908= relative molecular mass of KTF 119862 = molar

concentration or strength of oxidant in mol Lminus1 119899 = numberof moles of Ce(IV) reacting with each mole of KTF

32 Spectrophotometry Using 119901-Dimethylaminobenzaldehyde(Method B) Different aliquots (02 05 4mL) of stan-dard 20120583gmLminus1 KTF solution in 4M HClO

4were trans-

ferred into a series of 10mL calibrated flasks by means ofa microburette and the total volume in all the flasks wasadjusted to 4mL by adding 4M HClO

4 To each flask 2mL

of 5MH2SO4and 1mL of 300 120583gmLminus1 Ce(IV) solution were

added and the content was mixed well After a standing


time of 10min 1mL of 05 119901-DMAB was added to eachflask and the volume was made up to mark with 4M HClO

4

After 5min the absorbance of the each coloured product wasmeasured at 460 nm against water

33 Spectrophotometry Using 119900-Dianisidine (Method C) Var-ying aliquots (020 05 50mL) of a standard 20120583gmLminus1KTF solution were transferred into a series of 10mL vol-umetric flasks using a microburette and the total volumewas brought to 5mL by adding water To each flask 1mL of5M H

2SO4followed by 1mL of 100120583gmLminus1 Ce(IV) solution

were added and the content was mixed well and kept asidefor 10min at ambient temperature Finally 1mL of 005 119900-dianisidine was added to each flask the volume was made upto mark with water and mixed well The absorbance of eachsolution was measured at 470 nm against water blank after5min

A standard graph was prepared by plotting absorbanceagainst concentration and the unknown concentration wasread from the graph or computed from the regressionequation derived using Beerrsquos law data

34 Procedure for the Analysis of Tablet Two hundred tabletswere weighed and finely powdered An accurately weighedquantity of the tablet powder equivalent to 100mg KTF wastransferred into a 50mL calibrated flask and about 30mLwater The content of the flask was shaken for 20min andfinally the volume was completed to the mark with waterThe content was mixed well and filtered through a WhatmanNo 42 filter paper First 5mL portion of the filtrate wasdiscarded and a suitable aliquot of the filtrate (2mgmLminus1KTF) was then subjected to titrimetric analysis (method A)This tablet extract was diluted stepwise to get 20 120583gmLminus1KTF with water used in spectrophotometry (method C)by following the procedure described earlier Tablet extractequivalent to 20120583gmLminus1 KTF was prepared separately using4M HClO

4and subjected to analysis in spectrophotometric

method B by following the assay procedure described earlier

35 Procedure for the Analysis of Placebo Blank and SyntheticMixture A placebo blank containing starch (30mg) acacia(35mg) hydroxyl cellulose (35mg) sodium citrate (40mg)talc (30mg) magnesium stearate (45mg) and sodium algi-nate (35mg) was prepared by combining all components toform a homogeneous mixture A 50mg of the placebo blankwas accurately weighed and its solution was prepared asdescribed under ldquotabletsrdquo and then subjected to analysis byfollowing the general procedure

A syntheticmixturewas prepared by adding an accuratelyweighed 100mg of KTF to about 150mg of the placebomentioned above The extraction procedure applied fortablets was applied to prepare 2mgmLminus1 KTF solution Thiswas diluted to get 20 120583gmLminus1 KTF solutions with respectivesolvents and used in spectrophotometric methods Threedifferent volumes of the resulting synthetic mixture solutionwere subjected to analysis by following the respective generalprocedure

4 Results and Discussion

KTF is reported to undergo oxidation with NBS [22] andalso cerium(IV) has been used as an oxidimetric reagent forthe assay of many oxidisable drugs [29ndash33]The present workis based on the oxidation of the sulphur atom of the KTFmolecule by ameasured excess of cerium(IV) in acidmediumand the surplus oxidant was determined by either titrimetryor spectrophotometry

41 Titrimetry KTF was found to react with Ce(IV) sulphatein sulphuric acid medium The titrimetric method (methodA) involves oxidation of KTF by a known excess of Ce(IV)in sulphuric acid medium with the formation of ketotifensulphoxide and the unreacted oxidant was determined byback titration with FAS H

2SO4medium was favored over

HCl andHClO4medium since the reactionwas found to yield

a regular stoichiometry in the concentration range studiedReproducible and regular stoichiometry was obtained when065ndash129M H

2SO4concentration was maintained Hence

5mL of 5M H2SO4solution in a total volume of 25mL

(1M H2SO4overall) was found to be the most suitable

concentration for the quantitative reaction between KTF andCe(IV) Under the optimized reaction condition there wasfound to be a definite reaction stoichiometry of 1 2 betweenKTF and Ce(IV) within the range of 2ndash18mg of KTF

42 Spectrophotometry In spectrophotometry (method B)the unreacted Ce(IV) was treated with p-DMAB in HClO

4

medium to yield formic acid and p-dimethylaminophenolwhich upon further oxidation gave the correspondingquinoimine derivative [35] measured at 460 nm and inmethod C the surplus oxidant was treated with o-dianisidinein acid medium to form the orange red colour product andmeasured at 470 nm

In methods B and C the increasing concentrations ofdrug added to a fixed concentration of Ce(IV) yield decreas-ing concentrations of Ce(IV) and this concomitant decreasein concentration results in decreasing absorbance values ofits reaction product with p-dimethylaminobenzaldehyde inmethod B and with o-dianisidine in method C

5 Method Development

51 Absorption Spectra The addition of p-DMAB to Ce(IV)resulted in the formation of yellowish red coloured productwith maximum absorption at 460 nm against blank and thedecrease in the absorption intensity at 460 nm caused by thepresence of the drug was directly proportional to the amountof the drug reacted in method B shown in Figure 2

InmethodC the orange coloured product of Ce(IV) witho-dianisidine shows maximum absorption at 470 nm againstits corresponding reagent blank as shown in Figure 3 and thedecrease in the absorption intensity at 470 nm caused by thepresence of the drug was directly proportional to the amountof the drug


340 360 380 400 420 440 460 480 500 520 540 5600

01

02

03

04

05

06

07

08

09

Abso

rban

ce

ab

cd

Wavelength (nm)

Figure 2 Absorption spectra method B (a b c and d areabsorption spectra of blank 2 4 and 8 20120583gmLminus1 KTF resp)

360 400 440 480 520 560 600

01

02

03

04

05

06

07

08

09

ab

cd

Abso

rban

ce

Wavelength (nm)

Figure 3 Absorption spectra method C (a b c and d areabsorption spectra of blank 2 6 and 8120583gmLminus1 KTF resp)

52 Selection of Reaction Medium Perchloric acid (4M)medium was found ideal for rapid and quantitative reactionbetween KTF and Ce(IV) and to obtain maximum andconstant absorbance values due to Ce(IV)-p-DMAB reactionproduct at 460 nm This may be attributed to the highestoxidation potential of Ce(IV) in HClO

4(119864119900= 175V) as

compared to that of Ce(IV) in H2SO4(119864119900= 144V) HNO

3

(119864119900= 161V) or HCl (119864

119900= 128V) [36] Therefore all the

solutions (ALB Ce(IV) and p-DMAB) were prepared in 4Mperchloric acid throughout the investigation and the samewas maintained as reaction medium in method B

53 Optimization of Ce(IV) Concentration for Methods Band C In method B to fix the optimum concentration of

Ce(IV) different concentrations of oxidant were reacted witha fixed concentration of p-DMAB in HClO

4medium and the

absorbance was measured at 460 nm A constant and maxi-mum absorbance resulted was 30 120583gmLminus1 Ce(IV) and hencedifferent concentrations of KTF were reacted with 1mL of300 120583gmLminus1 Ce(IV) in HClO

4medium before determining

the residual Ce(IV) This facilitated the optimization of thelinear dynamic range over which procedure could be appliedfor the assay of KTF In method C 10 120583gmLminus1 Ce(IV) gavea constant and maximum absorbance with o-dianisidine at470 nm and hence 1mL of 100 120583gmLminus1 Ce(IV) was fixed asoptimum

54 Study of Reaction Time and Stability of the ColouredSpecies Under the described experimental conditions thereaction between KTF and Ce(IV) was complete within10min at room temperature (28 plusmn 2∘C) After the additionof p-DMAB a standing time of 5min was necessary for theformation of coloured product and thereafter the absorbanceof the coloured product was stable for more than an hour inmethod B

In method C with fixed concentrations of KTF Ce(IV)ODS and acid the absorbance was measured by differentintervals of time which showed that reaction time is fiveminutes and the coloured product is stable for 15min

55 Effect of Diluent In order to select proper solvent fordilution different solvents were triedThe highest absorbancevalues were obtained when 4M HClO

4was used as diluting

solvent and substitution of 4M HClO4by other solvents

(methanol water 6M HClO4) resulted in decrease in the

absorbance values inmethod B InmethodC o-dianisidine isprepared in ethanol and drug in water and water as a diluentgave maximum absorbance

6 Method Validation

61 Linearity and Sensitivity The present methods werevalidated for linearity selectivity precision accuracy robust-ness ruggedness and recovery Over the range investi-gated (2ndash18mg) a fixed stoichiometry of 1 1 [KTF Ce(IV)]was obtained in titrimetry which served as the basis forcalculations In spectrophotometry the calibration graphswere found to be linear from 04ndash80120583gmLminus1 and 04ndash100 120583gmLminus1 KTF in method B and method C respectivelyin the inverse manner

The calibration graphs are given by the equation

119884 = 119886 + 119887119883 (2)

(where 119884 = absorbance 119886 = intercept 119887 = slope and 119883 =concentration in 120583gmLminus1) obtained by the method of leastsquares Sensitivity parameters such as molar absorptivityand Sandellrsquos sensitivity values and the limits of detection(LOD) and quantification (LOQ) were calculated accordingto the ICH guidelines [37] using the following formulae

LOD = 33 119878slope LOQ = 10 119878

slope (3)


Table 2 Sensitivity and regression parameters

Parameter Method B Method C120582max nm 460 470Colour stability min 60 15Linear range 120583gmLminus1 04ndash80 04ndash10Molar absorptivity (120576) Lmolminus1 cmminus1 40 times 104 37 times 104

Sandell sensitivitylowast 120583g cmminus2 00105 00136Limit of detection (LOD) 120583gmLminus1 039 043Limit of quantification (LOQ) 120583gmLminus1 119 132Regression equation 119884lowastlowast

Intercept (119886) 08744 08082Slope (119887) minus00914 minus00815Standard deviation of 119886 (119878

119886) 22 times 10minus2 66 times 10minus2

Standard deviation of 119887 (119878119887) 49 times 10minus3 73 times 10minus3

Regression coefficient (119903) minus09998 minus09990lowastLimit of determination as the weight in 120583g per mL of solution which corresponds to an absorbance of 119860 = 0001 measured in a cuvette of cross-sectionalarea 1 cm2 and 119897 = 1 cm lowastlowast119884 = 119886 + 119887119883 where 119884 is the absorbance119883 is concentration in 120583gmLminus1 119886 is intercept and 119887 is slope

Table 3 Results of intraday and interday accuracy and precision study

Method KTF takenmg120583gmLminus1

Intraday accuracy and precision (119899 = 7) Interday accuracy and precision (119899 = 7)KTF foundmg120583gmLminus1 RE RSD KTF found

mg120583gmLminus1 RE RSD

A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

In method A KTF takenfound is in mg and it is 120583gmLminus1 in method B and CRE relative error () RSD relative standard deviation ()

where 119878 is the standard deviation of the absorbance of sevenblank readings These are summarized in Table 2

62 Accuracy and Precision The repeatability of the pro-posed methods was determined by performing five replicatedeterminations The intra-day and inter-day variation in theanalysis of KTF was measured at three different levels Theaccuracy of an analytical method expresses the closenessbetween the reference value and the found value Accuracywas evaluated as percentage relative error between the mea-sured and taken amountsconcentrations The results of thisstudy are compiled in Table 3 and speak of the excellentintermediate precision (RSD le 290) and accuracy (RE le242) of the results

63 Robustness andRuggedness To evaluate the robustness ofthe methods two important experimental variables namelystanding time and volume of H

2SO4 were slightly varied

and the capacity of all the methods was found to remain

unaffected by small deliberate variations The results of thisstudy are presented in Table 4 and indicate that the proposedmethods are robust Method ruggedness was demonstratedhaving the analysis done by four analysts and also by a singleanalyst performing analysis on four different apparatus orinstruments in the same laboratory Intermediate precisionvalues (RSD) in both instances were in the range of059ndash296 indicating acceptable ruggedness The resultsare presented in Table 4

64 Selectivity In the analysis of placebo blank there wasno measurable consumption of Ce(IV) in titrimetry and thesame absorbance value as obtained for the reagent blankwas recorded in method B and method C suggesting thenoninterference by the inactive ingredients added to preparethe placebo

In method A 5mL of the resulting solution prepared byusing synthetic mixture was assayed titrimetrically (119899 = 5)and yielded a percentage of recovery of 1023 plusmn 062KTF Inspectrophotometry 2mL of 20120583gmLminus1 KTF in method B


Table 4 Method robustness and ruggedness expressed as intermediate precision


Robustness RuggednessH2SO4 volume mL( RSD) 119899 = 3

Reaction time min( RSD) 119899 = 3

Ineranalysis ( RSD)119899 = 4

Intercuvettesburettes( RSD) 119899 = 4

A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296

In titrimetry standing times were 8 10 and 12minIn spectrometric methods B and C reaction time 10 plusmn 1min volume of H2SO4 2 plusmn 02mL and 1 plusmn 02mL varied respectively

Table 5 Results of analysis of tablets by the proposed methods and statistical comparison with the reference method

Tablets analysed Label claimmgtablet

Foundlowast (percent of label claim plusmn SD)

Reference method Proposed methodsMethod A Method B Method C

Asthafen 1 1008 plusmn 0911014 plusmn 089 1028 plusmn 191 1021 plusmn 175119905 = 105 119905 = 211 119905 = 216

119865 = 105 119865 = 441 119865 = 37

Ketasma 1 1023 plusmn 1021006 plusmn 098 1028 plusmn 136 1013 plusmn 088119905 = 269 119905 = 066 119905 = 166

119865 = 108 119865 = 178 119865 = 134

lowastMean value of five determinationsTabulated 119905 value at the 95 confidence level is 278Tabulated 119865 value at the 95 confidence level is 639

and 3mL of 20120583gmLminus1 KTF in method C when subjected toanalysis (119899 = 5) yielded percentage of recoveries of 9824and 1018 KTF with standard deviations of 174 and 232respectively These results complement the findings of theplacebo blank analysis with respect to selectivity

65 Application to Tablet Analysis Commercial KTF tabletswere analyzed using the developed methods and also areferencemethod [38]The referencemethod involves poten-tiometric titration of KTF in anhydrous acetic anhydridemdashacetic acid medium with acetous perchloric acid The resultsobtained were compared statistically by Studentrsquos 119905-test andthe variance-ratio 119865-test The calculated 119905 and 119865 values didnot exceed the tabulated values of 278 and 639 at the 95 confidence level and for four degrees of freedom indicatingclose similarity between the proposed methods and thereference method with respect to accuracy and precisionThese results are summarized in Table 5

66 Recovery Study To further ascertain the accuracy andreliability of the methods recovery experiments were per-formed via standard-addition procedure Preanalysed tablet

powder was spikedwith pure KTF at three different levels andthe total was found by the proposed methods Each deter-mination was repeated three times The percent recovery ofpure KTF added (Table 6) was within the permissible limitsindicating the absence of inactive ingredients in the assay

7 Conclusions

Three methods have been developed for determination ofketotifen fumarate in bulk drug and in its tablets and vali-dated as per the current ICH guidelines The present visualtitrimetricmethod is simple and economical compared to thereported coulometric method [23] The spectrophotometricmethods are characterized by simplicity since they do notinvolve any critical experimental variable and are free fromtedious and time-consuming extraction steps and use oforganic solvents unlike many previous methods as indicatedin Table 1 The method using o-dianisidine looks moresensitive than most existing methods Both have additionaladvantages of ease of operation and possibility of carryingthem out with a common laboratory instrument unlikemany other instrumental methods reported for ketotifenThey are characterized by high selectivity and comparable


Table 6 Results of recovery study via standard addition method with tablet

Method Tablet studied KTF in tabletmg120583gmLminus1

Pure KTF addedmg120583gmLminus1

Total foundmg120583gmLminus1

Pure KTFlowastPercent plusmn SD

A Ketasma-1603 30 924 1023 plusmn 198603 60 1222 1016 plusmn 125603 90 1529 1013 plusmn 208

B Ketasma-1303 15 454 1011 plusmn 126303 30 609 1021 plusmn 198303 45 759 1014 plusmn 134

C Ketasma-1205 10 306 101 1 plusmn 163205 20 403 9936 plusmn 128205 30 512 1024 plusmn 153

lowastmg in method A 120583gmLminus1 in methods B and C lowastMean value of three determinations

sensitivity with respect to the existing methods The accu-racy reproducibility simplicity and cost-effectiveness of themethods suggest their application in the quality controllaboratories where the modern and expensive instrumentsare not available

Conflict of Interests

Theauthors declare that they have no conflict of interests withthe company name used in the paper

Acknowledgments

The authors thank Cipla India Ltd Bangalore India forproviding pure ketotifen fumarate The authors are gratefulto the authorities of the University of Mysore Mysore Indiafor permission and facilities

References

[1] S C Sweetman Martindale The Complete Drug ReferencePharmaceutical Press London UK 2005

[2] F Q Alali B M Tashtoush and N M Naji ldquoDetermination ofketotifen in human plasma by LC-MSrdquo Journal of Pharmaceuti-cal and Biomedical Analysis vol 34 no 1 pp 87ndash94 2004

[3] C DolleryTherapeutic Drugs vol 2 of pp K25ndashK28 ChurchillLivingstone London UK 2nd edition 1999

[4] M A Abounassif H A El-Obeid and E A GadkariemldquoStability studies on some benzocycloheptane antihistaminicagentsrdquo Journal of Pharmaceutical and Biomedical Analysis vol36 no 5 pp 1011ndash1018 2005

[5] G L Chen and H Qu ldquoHPLC determination of ketotifenfumarate in compound metamizol sodium tabletsrdquo YaowuFenxi Zazhi vol 23 no 2 pp 123ndash125 2003

[6] I P Nnane L A Damani and A J Hutt ldquoDevelopmentand validation of stability indicating high-performance liquidchromatographic assays for ketotifen in aqueous and silicon oilformulationsrdquo Chromatographia vol 48 no 11-12 pp 797ndash8021998

[7] S S Zarapkar N J Bhounsule and U P Halkar ldquoHigh per-formance liquid chromatographic determination of ketotifen I

hydrogen fumarate in pharmaceuticalsrdquo Indian Drugs vol 29no 8 pp 365ndash366 1992

[8] G Hoogewijs and D L Massart ldquoDevelopment of a standard-ized analysis strategy for basic drugs using ion-pair extractionand high-performance liquid chromatographymdashIII Analysis ofpharmaceutical dosage formsrdquo Journal of Pharmaceutical andBiomedical Analysis vol 2 no 3-4 pp 449ndash463 1984

[9] S Muralidharan L B Han Y Ming J Lau K Sailishni andS Arumugam ldquoSimple and accurate estimation of ketotifenfumarate by RP-HPLCrdquo International Journal of Pharmaceuti-cal Chemical and Biological Sciences vol 2 no 3 pp 392ndash3962012

[10] M H Semreen ldquoOptimization and validation of HPLCmethodfor the analysis of ketotifen fumarate in a pharmaceutical for-mulationrdquoBulletin of Pharmaceutical Sciences AssiutUniversityvol 28 no 2 pp 291ndash296 2005

[11] NM Sanghavi K A Puranik andMM Samarth ldquoAnalysis ofketotifen fumarate by high performance thin layer chromatog-raphyrdquo Indian Drugs vol 32 no 1 pp 53ndash54 1995

[12] N Kyung-Don T Sung-Kwon P Ji-Sun et al ldquoBioequivalenceassessment of Fumatifen tablet to Zaditen tablet (ketotifenfumarate 1mg) by liquid chromatography tandem mass spec-trometryrdquo Journal of Pharmaceutical Investigation vol 42 no4 pp 221ndash228 2012

[13] M Zhou Y Li Y Ma W Wang J Mi and H Chen ldquoDeter-mination of ketotifen fumarate by capillary electrophoresiswith tris(221015840-bipyridyl) ruthenium(II) electrochemilumines-cence detectionrdquo Luminescence vol 26 no 5 pp 319ndash323 2011

[14] C S P Sastry and P Y Naidu ldquoSpectrofluorimetric estimationof ketotifen and terfenadine in pharmaceutical formulationsrdquoIndian Drugs vol 35 no 3 pp 147ndash149 1998

[15] P M Bersier W Szczepaniak and M Ren ldquoDirect differentialpulse polarographic and adsorptive stripping voltammetricassay of ketotifen in tabletsrdquo Archiv der Pharmazie vol 325 no5 pp 253ndash259 1992

[16] M E Mohamed and H Y Aboul-Enein ldquoSpectrophotometricand differential pulse polarographic methods of analysis forketotifen hydrogen fumaraterdquoDrug Development and IndustrialPharmacy vol 12 no 5 pp 733ndash746 1986

[17] W Szczepaniak T Cychowska and T Przadka ldquoSpectrophoto-metric determination of ketotifen in pharmaceutical prepara-tions after isolation on ion-exchangerrdquo Acta poloniae pharma-ceutica vol 49 no 4 pp 3ndash5 1992


[18] H Hopkała and J Drozd ldquoIon-selective electrodes for thedetermination of antihistaminic drug ketotifenrdquo Chemia Anal-ityczna vol 44 no 3 pp 603ndash609 1999

[19] E Y Z Frag G G Mohamed Gehad M M Khalil and M AHwehy ldquoPotentiometric determination of ketotifen fumarate inpharmaceutical preparations and urine using carbon paste andPVC membrane selective electrodesrdquo International Journal ofAnalytical Chemistrypages vol 2011 Article ID 604741 7 pages2011

[20] L J Li W Y Gao D C Hu Z Cai and Y Q Li ldquoElec-trochemiluminescence method for determination of ketotifenfumarate on glassy carbon electrode modified with platinum-multi-walled carbon nanotube modified electroderdquo Fenxi CeshiXuebao vol 29 no 11 pp 1114ndash1120 2010

[21] N Fei and L Jiuru ldquoDetermination of ketotifen by using calceinas chemiluminescence reagentrdquo Analytica Chimica Acta vol592 no 2 pp 168ndash172 2007

[22] S H He K J Tian S Q Zhang and W Y Yu ldquoDeterminationof ketotifen fumarate based on the chemiluminescence reactionof luminol with ferricyaniderdquo Fenxi Ceshi Xuebao vol 24 no 2pp 98ndash99 2005

[23] W Ciesilski R Zakrzewski and U Złobinska ldquoCoulometrictitration of ketotifen in tabletsrdquo Pharmazie vol 60 no 3 pp237ndash238 2005

[24] N El-Kousy and L I Bebawy ldquoDetermination of some anti-histaminic drugs by atomic absorption spectrometry and col-orimetric methodsrdquo Journal of Pharmaceutical and BiomedicalAnalysis vol 20 no 4 pp 671ndash679 1999

[25] C S P Sastry and P Y Naidu ldquoSpectrophotometric estima-tion of ketotifen fumarate in pharmaceutical formulationsrdquoMikrochimica Acta vol 127 no 3-4 pp 219ndash223 1997

[26] R T Sane N L Chonkar S R Surve M G Gangrade andV V Bapat ldquoExtractive colorimetrics estimation of (i) ticlopi-dine hydrochloride (ii) buspirone hydrochloride (iii) nefopamhydrochloride and (iv) ketotifen fumarate from pharmaceuticalpreparationsrdquo Indian Drugs vol 30 no 5 pp 235ndash239 1993

[27] M Amanlou M H Hoseinzadeh H Azizian E Souri and HFarsam ldquoDetermination of Ketotifen fumarate in raw materialand pharmaceutical products using ion-pair formationrdquo Ana-lytical Letters vol 40 no 16ndash18 pp 3267ndash3279 2007

[28] J Vachek ldquoPhotometric determination of Ketotifenrdquo Cesko-Slovenska Farmacie vol 36 no 4 pp 168ndash169 1987

[29] O Z Devi K Basavaiah H D Revanasiddappa and KB Vinay ldquoTitrimetric and spectrophotometric assay of pan-toprazole in pharmaceuticals using cerium(IV) sulphate asoxidimetric agentrdquo Journal of Analytical Chemistry vol 66 no5 pp 490ndash495 2011

[30] N Rajendraprasad K Basavaiah K Tharpa and K B VinayldquoQuantitative determination of olanzapine in tablets with vis-ible spectrophotometry using cerium(IV)sulphate and basedon redox and complexation Reactionsrdquo Eurasian Journal ofAnalytical Chemistry vol 4 no 2 pp 191ndash203 2009

[31] N Rajendraprasad and K Basavaiah ldquoHighly sensitive spec-trophotometric determination of olanzapine using cerium(IV)and iron(II) complexes of 110-phenanthroline and 22

1015840

-bipyridylrdquo Journal of Analytical Chemistry vol 65 no 5 pp482ndash488 2010

[32] K Basavaiah K Tharpa N Rajendraprasad S G Hiriyannaand K B Vinay ldquoSensitive cerimetric assay of olanzapine inpharmaceuticalsrdquo Biomedical Journal vol 4 no 2 pp 159ndash1752009

[33] M S Raghu and K Basavaiah ldquoSimple sensitive and eco-friendly methods for the determination of methdilazine intablets and syrup using cerium (IV)rdquoChemical Sciences Journalvol 2012 article CSJ-68 2012

[34] A I Vogel A Text-Book of Quantitative Inorganic AnalysisThe English Language Book Edition Society London UK 3rdedition 1961

[35] B R DasGupta and D A Boroff ldquoQuantitative spectropho-tometric determination of hydrogen peroxide with para-dimethylaminobenzaldehyderdquo Analytical Chemistry vol 40no 13 pp 2060ndash2062 1968

[36] G D Christian Text Book of Analytical Chemistry John Wileyamp Sons Singapore 2007

[37] ldquoValidation of analytical procedures text and methodologyQ2 (R 1) complementary guideline on methodologyrdquo in Pro-ceedings of the International Conference on Hormonisation ofTechnical Requirements for Registration of Pharmaceuticals forHuman Use ICH Harmonised Tripartite Guideline LondonUK November 1996

[38] British Pharmacopoeia Volume I and II Her Majestyrsquos Sta-tionery Office London UK 2009

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


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Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

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Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy



Analytical ChemistryVolume 2014

Journal of


Quantum Chemistry


Organic Chemistry International


CatalystsJournal of

ElectrochemistryInternational Journal of



O

S

N

HO OHO

O

CH3

Figure 1 Structure of KTF

ketotifen molecule can be found in the literature El-Kousyand Bebawy [24] have developed three methods for theassay of KTF in bulk drug and in tablets the first methodwas based on extraction of drug-cobalt thiocyanate ternarycomplex with methylene chloride and estimation by indirectatomic absorption method via the determination of thecobalt content in the complex after extraction in 01Mhydrochloric acid at 2407 nm The second method is basedon the formation of orange red ion pair by the reaction ofKTF and molybdenum thiocyanate with absorption maximaat 4695 nm in dichloromethane The third method was acharge transfer reaction between drug and 23-dichloro-56-dicyano-p-benzoquinone in acetonitrile medium Sastryand Naidu [25] have determined the drug in tablets andsyrup based on the reduction of Folin-Ciocalteau reagentto a blue coloured chromogen measurable at 720 nm inthe same article KTF was treated with a measured excessof N-bromosuccinimide (NBS) the unreacted oxidant wasreacted with celestine blue and the change in absorbancewas measured at 540 nmThe third method was based on theformation of colored species by the coupling of the diazotizedsulphanilamide and absorbance of the colored species wasmeasured at 520 nm

There are three reports on the use of ion-pair reaction forthe assay of KTF An extractive spectrophotometric proce-dure was based ion-pair reaction using Azocarmine G as ion-pair reagent at pH 15 The ion-pair complex extracted intoCHCl

3was measured at 540 nm [25] Sane et al [26] have

described four extractive spectrophotometric proceduresbased on this reaction using bromophenol blue bromoth-ymol green bromothymol blue and bromocresol purpleas ion-pair reagents in acidic medium The drug has alsobeen determined spectrophotometrically based on ion-paircomplex formation with bromocresol green [27] at pH 30followed by extraction into chloroform and measurement at423 nm Beerrsquos law is obeyed over the concentration range515ndash6191120583gmLminus1 KTFThe charge-transfer reaction of KTFwith picric acid was developed by Vachek [28] The methodinvolves extraction of the picric acid-drug complex intochloroform and measurement of the extract at 405 nm

The reported spectrophotometric methods suffer fromsome other disadvantage such as narrow linear range poorsensitivity dependence on critical experimental variablestedious and time-consuming extraction steps heating stepandor use of expensive reagent or large amounts of organicsolvents as indicated in Table 1

From the foregoing paragraphs it is clear that cerium(IV)despite its strong oxidizing power versatility and high stabil-ity in solution has not been applied for the assay of ketotifenThis paper describes for the first time the application ofacidic cerium(IV) to the titrimetric and spectrophotometricdetermination of KTF using p-dimethyl amino benzaldehydeand o-dianisidine as chromogenic agents cerium(IV) hasearlier been widely applied for the assay of a variety ofpharmaceuticals [29ndash33]

2 Experimental

21 Apparatus A Systronics model 106 digital spectropho-tometer (Systronics Ahmedabad Gujarat India) with 1 cmpath length matched quartz cells was used to record theabsorbance values

22 Materials All chemicals used were of analytical reagentgrade Double distilled water was used throughout the inves-tigation Pharmaceutical grade KTF (9978 percent pure) wasprocured from Cipla India Ltd Mumbai India as a giftand used as received Asthafen-1 (Torrent pharmaceuticalsSikkim India) and Ketasma-1 (Sun pharmaceuticals SikkimIndia) tablets were purchased from local commercial market

23 Reagents and Chemicals Cerium(IV) Sulphate(0005M) An approximately 001M solution was preparedby dissolving about 252 g of the chemical Ce(SO

4)2sdot4H2O

(Loba Chemie Pvt Ltd Mumbai India) in 05M sulphuricacid with the aid of heat and diluting to 250mLwith the sameacid and standardized using standard ferrous ammoniumsulphate solution (FAS) [34] It was used for titrimetric workand diluted to obtain working concentrations of 300 and100 120583gmLminus1 cerium(IV) for spectrophotometric methods Band C respectively with the same solvent

Perchloric Acid (4M) Perchloric acid (4M) was prepared bydiluting appropriate volume of commercially available acid(70 Merck Mumbai India) with water

Sulphuric Acid (5M) A 5M sulphuric acid was prepared byappropriate dilution of concentrated acid (98 Sp gr 184Merck Mumbai India) with water and used in bothmethodsB and C

Ferroin Indicator It was prepared by dissolving 0742 g of 110-phenanthroline monohydrate in 50mL of 0025M ferroussulphate solution (0348 g of ferrous sulphate heptahydrate in50mL water)

119901-Dimethylamino Benzaldehyde (119901-DMAB) (05) An accu-rately weighed 05 g of119901-DMAB (MerckMumbai India) wastransferred to a 100mL volumetric flask and dissolved in 4MHClO

4and the volume was made up to the mark with the

same solvent

119900-Dianisidine (ODS) (005) An accurately weighed 50mgof 119900-dianisidine (Merck Mumbai India) was transferred to




(nm)





4695588

5ndash37510ndash80


[24]

2



720540520540



[25]

3




[26]



[27]




Thiswork




4


4and used for assay

3 Assay Procedures





119908times 119862

119899 (1)





4were trans-


4 To each flask 2mL





4






















4







340 360 380 400 420 440 460 480 500 520 540 5600

01

02

03

04

05

06

07

08

09

Abso

rban

ce

ab

cd

Wavelength (nm)


360 400 440 480 520 560 600

01

02

03

04

05

06

07

08

09

ab

cd

Abso

rban

ce

Wavelength (nm)



4(119864119900= 175V) as


3

(119864119900= 161V) or HCl (119864





4medium and the











6 Method Validation



119884 = 119886 + 119887119883 (2)


LOD = 33 119878slope LOQ = 10 119878

slope (3)













A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

















A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of






(nm)





4695588

5ndash37510ndash80


[24]

2



720540520540



[25]

3




[26]



[27]




Thiswork




4


4and used for assay

3 Assay Procedures





119908times 119862

119899 (1)





4were trans-


4 To each flask 2mL





4






















4







340 360 380 400 420 440 460 480 500 520 540 5600

01

02

03

04

05

06

07

08

09

Abso

rban

ce

ab

cd

Wavelength (nm)


360 400 440 480 520 560 600

01

02

03

04

05

06

07

08

09

ab

cd

Abso

rban

ce

Wavelength (nm)



4(119864119900= 175V) as


3

(119864119900= 161V) or HCl (119864





4medium and the











6 Method Validation



119884 = 119886 + 119887119883 (2)


LOD = 33 119878slope LOQ = 10 119878

slope (3)













A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

















A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of





4






















4







340 360 380 400 420 440 460 480 500 520 540 5600

01

02

03

04

05

06

07

08

09

Abso

rban

ce

ab

cd

Wavelength (nm)


360 400 440 480 520 560 600

01

02

03

04

05

06

07

08

09

ab

cd

Abso

rban

ce

Wavelength (nm)



4(119864119900= 175V) as


3

(119864119900= 161V) or HCl (119864





4medium and the











6 Method Validation



119884 = 119886 + 119887119883 (2)


LOD = 33 119878slope LOQ = 10 119878

slope (3)













A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

















A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of




340 360 380 400 420 440 460 480 500 520 540 5600

01

02

03

04

05

06

07

08

09

Abso

rban

ce

ab

cd

Wavelength (nm)


360 400 440 480 520 560 600

01

02

03

04

05

06

07

08

09

ab

cd

Abso

rban

ce

Wavelength (nm)



4(119864119900= 175V) as


3

(119864119900= 161V) or HCl (119864





4medium and the











6 Method Validation



119884 = 119886 + 119887119883 (2)


LOD = 33 119878slope LOQ = 10 119878

slope (3)













A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

















A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of















A500 506 120 180 512 242 290100 1012 162 140 1015 151 243150 1480 134 094 1472 158 192

B20 202 123 172 203 162 11840 396 162 087 394 126 15860 608 133 146 617 190 088

C40 394 073 143 395 114 21260 606 106 109 611 184 17980 790 121 118 788 147 109

















A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of










A50 088 163 081 085100 133 183 193 123150 103 059 089 096

B20 260 211 211 23840 271 136 263 18260 179 180 158 283

C40 266 270 201 27160 245 183 279 19980 172 127 169 296







119865 = 105 119865 = 441 119865 = 37


119865 = 108 119865 = 178 119865 = 134






7 Conclusions















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of
















Acknowledgments


References


































1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of


















1015840


















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of












Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy




Journal of


Quantum Chemistry




CatalystsJournal of



Documents

Titrimetric and Spectrophotometric Methods for the …eprints.uni-mysore.ac.in/16569/1/697651.pdf · cobalt content in the complex after extraction in 0.1M ... in sulphuric acid medium