Research Article Ultratrace Determination of Cr(VI) and Pb

Hindawi Publishing CorporationJournal of Analytical Methods in ChemistryVolume 2013 Article ID 629495 8 pageshttpdxdoiorg1011552013629495

Research ArticleUltratrace Determination of Cr(VI) and Pb(II)by Microsample Injection System Flame AtomicSpectroscopy in Drinking Water and Treated andUntreated Industrial Effluents

Jameel Ahmed Baig123 Tasneem Gul Kazi1 Latif Elci2 Hassan Imran Afridi1

Muhammad Irfan Khan3 and Hafiz Muhammad Naseer3

1 National Centre of Excellence in Analytical Chemistry University of Sindh 76080 Jamshoro Pakistan2 Chemistry Department Pamukkale University 20017 Denizli Turkey3 Environmental Sciences International Islamic University 44000 Islamabad Pakistan

Correspondence should be addressed to Jameel Ahmed Baig jab mughalyahoocom

Received 15 May 2013 Accepted 29 July 2013

Academic Editor Miguel de la Guardia

Copyright copy 2013 Jameel Ahmed Baig et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Simple and robust analytical procedures were developed for hexavalent chromium (Cr(VI)) and lead (Pb(II)) by dispersive liquid-liquid microextraction (DLLME) using microsample injection system coupled with flame atomic absorption spectrophotometry(MIS-FAAS) For the current study ammonium pyrrolidine dithiocarbamate (APDC) carbon tetrachloride and ethanol wereused as chelating agent extraction solvent and disperser solvent respectively The effective variables of developed method havebeen optimized and studied in detail The limit of detection of Cr(VI) and Pb(II) were 0037 and 0054 120583gL respectively Theenrichment factors in both cases were 400 with 40mL of initial volumesThe relative standard deviations (RSDs 119899 = 6) were lt4The applicability and the accuracy of DLLME were estimated by the analysis of Cr(VI) and Pb(II) in industrial effluent wastewaterby standard additionmethod (recoveries gt96)The proposedmethodwas successfully applied to the determination of Cr(VI) andPb(II) at ultratrace levels in natural drinking water and industrial effluents wastewater of Denizli Moreover the proposed methodwas compared with the literature reported method

1 Introduction

Lead pollution is one of the most serious environmentalproblems because of their stability at contaminated sites thereduction of enzymatic activities and several other compli-cations in human plants and animals [1] It is introducedinto water bodies (lakes streams and rivers) through thecombustion of fossil fuels smelting of sulfide ore and acidmine drainage [2] Characteristic indications of lead toxicityare abdominal pain anaemia headaches and convulsionschronic nephritis of the kidney brain damage and centralnervous systemdisorders [3]TheUS Environmental Protec-tion Agency (EPA) has classified lead as a Group B2 human

carcinogen [3] Chromium occurs in higher concentration inthe wastes from electroplating paints dyes chrome tanningand paper industries [4] Cr(III) is an essential componenthaving an important role in the glucose lipid and proteinmetabolism whereas Cr(VI) is believed to be toxic andcarcinogenic [5] In addition there is an increasing interestin the determination of Cr(VI) and Pb at trace level becauseof persistence in the environment and bio-accumulative effectin living organisms [6]

Flame atomic absorption spectrometry (FAAS) is oneof the most conventional techniques for the determinationof trace metal ions because of the relatively simple andinexpensive equipment [7ndash9] However a preconcentration

2 Journal of Analytical Methods in Chemistry

andor separation step prior the final measurement is usuallyrequired for significant precise sensitive and accurate deter-mination in order to bring the analyte concentration into thedynamic range of the detector or to isolate the analyte fromthe desirable matrix constituents [3 4 10 11]

The preconcentration methods like solvent extractionion exchange adsorption and coprecipitation were fre-quently used for trace level analysis of Cr(VI) and Pb(II)[12ndash17] Liquid-liquid extraction based on transfer of ana-lyte from the aqueous sample to a water-immiscible sol-vent is being widely employed for sample preparation [18]But these methods are time consuming needed significantchemical additives large secondary wastes along procedureand required complex equipment Miniaturization of liquidextraction methods can be achieved by a drastic reduction ofthe extractant phase volume three new methodologies havebeen developed that is single-drop microextraction hollowfibre liquid-phase microextraction and dispersive liquid-liquid microextraction [19] Among them dispersive liquid-liquid microextraction (DLLME) is effectively useful for theseparation and pre-concentration of organic and inorganiccontaminants in environmental samples in a single step [1820 21]

For the current study a new approach has been designedfor the simultaneous and selective determination of Cr(VI)and Pb(II) at trace level in environmental samples based onDLLME Ammonium pyrrolidine dithiocarbamate (APDC)has been used as a selective chelating agent for Cr(VI)and Pb(II) [22 23] The applicability of DLLME coupledwith microsample injection system flame atomic absorptionspectroscopy for Cr(VI) and Pb(II) preconcentration andseparation was adopted as evaluated in our previous work[24] The influence of the different analytical parameters forboth methods was investigated in detailed The proposedmethod was applied to tap water groundwater and industrialeffluent before and after treatment for evaluation of Cr(VI)and Pb(II)

2 Experimental

21 Sampling Six samples of each type of drinking water(tapwater and groundwater samples) were collected in Nov-ember 2011 from different sampling sites of Denizli Tur-key (situated between the coordinates 37∘4610158404810158401015840N and29∘0410158404810158401015840E in Aegean region) Whereas the industrial efflu-ent before and after treatment (six samples of each) fromwell organized industrial zone of Denizli with the assistanceof Denizli Environment Quality Laboratory (DENCEV)Theproposed methods (details are given below) were performedon the same week of sampling So the sample storage was notrequired

22 Reagents All solutions were prepared using ultrapurewater (resistivity 182MΩcm) obtained with a reverseosmosis system (Human Corporation Seoul Republic ofKorea) Standard solutions of Cr(VI) and Pb(II) were pre-pared by dilution of 1000 ppm certified standard solutionsFluka (Buchs Switzerland)Working standard solutions were

freshly prepared by appropriate dilution of the stock standardsolution Ammonium pyrrolidine dithiocarbamate (APDCFluka) was used as the chelating agent to form the hydropho-bic metal complexes A 5 (wv) of APDC solution wasprepared by dissolving suitable amount of APDC in ultrapurewater Buffer of pH 1-2 was prepared by adding an appropriateamount of hydrochloric acid Merck (Darmstadt Germany)and potassium chloride and buffer of pH 3ndash6 was preparedby adding an appropriate amount of acetic acid (Merck) andsodium acetate

23 Apparatus An atomic absorption spectrometer (Perki-nElmer AAnalyst 200) equipped with a chromium hollowcathode lamp an air-acetylene flame atomizer and hand-made microinjection system was used for determinationsThe wavelength lamp current and spectral bandwidth usedwere 3579 nm 25mA and 07 nm respectively The pHmeasurements were carried out with a pHmeter (WTW-pH-meter-720) A centrifuge (Hettich Centrifuge Germany) wasused to accelerate the phase separation processMicroinjector(Hamilton Switzerland) was used for sediment phase separa-tion

24 Preparation of Handmade Microsample Injection System(MIS) In routine practice a sample volume of 2ndash4mL isrequired for a single element determination by FAAS How-ever a small volume was obtained by each preconcentrationmethod (lt05mL) whereas there is need for high dilutionTo resolve this problem our group have made a microsampleinjection system (MIS) coupled to the nebulizer needleusing a PTFE capillary tube (length of 12 cm) attached withyellow micropipette tip (capacity 20ndash200120583L) as reported inour previous work [24] For simultaneous determination ofCr(VI) and Pb(II) 100mL was used for each analysis

25 Dispersive Liquid-Liquid Microextraction The Cr(VI)and Pb(II) were determined by DLLME using a complexingreagent (APDC) and resulted complex was enriched intoextraction solvent through disperser solvent To optimizeDLLME four replicate of sub-samples (40mL) of standardsolution containing 10 120583g Lminus1 Cr(VI) and Pb(II) in PTFEtubes (50mL in capacity) The pH was adjusted with appro-priate buffer solution in the range of 1ndash6 Then added 005ndash2 (wv) APDC and 1ndash4mL ethanol containing 100ndash400120583Ltetrachloride carbon was rapidly injected into the aqueoussolution with a 2550mL syringe As a result a turbid phaseimmediately was formed The acquired solution was cen-trifuged at 3000 rpm for 5min The CCl

4as sediment phase

was separated in the range of 80ndash90120583L by microinjector into2mL glass vial The residual phase was vaporized to drynessby electrical hot plate and dissolved in 01mL of 01molLHNO

3 The final solution was determined by MIS-FAAS

26 Determination of Cr(VI) and Pb(II) in Water and Indus-trial Effluents 40mL of replicate four subsamples of tapwater groundwater and industrial effluent were filtered withordinary filter papers to removed unsalable matrices andtaken in PTFE tubes (50mL in capacity) Then treated with

Journal of Analytical Methods in Chemistry 3

050

100150200250300350400450

0 1 2 3 4 5

Enric

hmen

t fac

tor

Volume (mL)

Volume of disperser solvent (ethanol)Volume of extraction solvent (CCl4)10

Figure 1 Influence of volume of the extraction solvent (CCl4

) anddispersive solvent (ethanol) on the enrichment factor of Cr(VI) andPb(II) at 40mL initial volume of water samples 025 APDC pH300 and 001mgL Cr(VI)Pb(II)

developed DLLME as illustrated above for determination ofCr(VI) and Pb(II) respectively

3 Results and Discussion

In order to attain higher enrichment factor and significantrecovery percentages of Cr(VI) and Pb(II) by DLLME cou-pled with MIS-FAAS the characteristic parameters wereinvestigated in detail Each experiment was repeated fourtimes and the results were presented with mean plusmn standarddeviation at 95 confidence intervals

31 Influence of the Extraction Solvent Type and VolumeThe extraction solvents with higher density than water weremostly used for DLLME procedure Among different sol-vents CHCl

3andCCl

4were selected for pre-concentration of

the Cr(VI) and Pb(II) on the basis of their high density andvapour pressure as well as less water solubility (19) Samplesolutions were tested using 10mL of ethanol (dispersersolvent) which contains 100 120583L of understudied extractionsolvents and rapidly injected into 400mL of the aqueoussample resulted from complex formation reaction In thisexperiment CCl

4and CHCl

3resulted in enrichment factors

of 400 plusmn 50 and 380 plusmn 80 respectively CCl4established the

maximum enrichment factor as compared to CHCl3because

of its low solubility less viscosity and polarity (19) Theformed sediment phase can easily be separated by a micro-injector As a result CCl

4was chosen as best extraction

solventTo evaluate the effect of the extraction solvent vol-

ume solutions containing different volumes of CCl4(100

to 400 120583L) were studied (Figure 1) It was observed thatthe enrichment factor of simultaneous preconcentration ofCr(VI) and Pb(II) by DLLME was decreased with increasingthe volume of CCl

4(Figure 1)This is due to the large volume

of sediment phase (80 to 320120583L) At the end of experimentalstudies 100 120583L volume ofCCl

4was selected for the subsequent

investigations

32 Influence of the Disperser Solvent Type and VolumeIn DLLME the dispersive solvent must be miscible bothaqueous phase and extraction solventThus different solvents(CH3CHO CH

3CN CH

3CH2OH and CH

3OH) were tested

as disperser solvent using 100mL of each disperser solventcontaining 100 120583L CCl

4(extraction solvent) However the

enrichment factors obtained by each studied dispersive sol-vent have no significant difference (119875 gt 005) But forthe lowest toxicity and standard deviation of CH

3CH2OH

further studies it have been chosen The effect of the volumeof CH

3CH2OH on the extraction recovery was also carried

out The effect of different volumes of CH3CH2OH (100ndash

400mL) was carried out at optimum experimental condi-tions as shown in Figure 1 The enrichment factor decreasedwhen the CH

3CH2OH volume increased Thus 100mL of

CH3CH2OH was chosen for further study

33 Effect of the Extraction Time Extraction time can bedefined as the time interval between injecting the mixtureof disperser solvent (CH

3CH2OH) and extraction solvent

(CCl4) into sample before starting to centrifuge [19] Depen-

dence of the enrichment factor upon extraction time wasstudied within a range of 50 secndash50min while the exper-imental conditions were kept constant It is observed thatextraction time has no significant effect on the enrichmentfactor and extraction efficiency of DLLME and phase separa-tion is completed in 50 to 100 sec

34 Salt Effect The solubility of understudied analytes andorganic extraction solvent in aqueous phase are usuallydecreased with the increase of salt concentration which isfavorable for reaching high recovery Therefore influenceof salt concentration was evaluated at 005ndash400 (wv)NaCl levels while other parameters were kept constantThe results showed that salt addition up to 100 did notaffect the enrichment factor considerably By increasing theionic strength (from 100 to 400) the solubility of theextraction solvent in the aqueous phase diminishes As aresult the volume of the sediment phase increases fromalmost 110 to 130 120583L which decreases the enrichment factorThe developed method can be applicable for separation ofchromium from saline solutions up to 100

35 Influence of Sample pH and Concentration of APDC ThepH plays an important role in the extraction of inorganiccompounds especially chromium in environmental samplesfor the complex formation reaction with complexing reagentincluding APDC In this experiment the effect of pH onthe extraction performance within the range of 1ndash6 wasinvestigated for Cr(VI) and Pb(II) as shown in Figure 2 Itcan be observed that the recovery of Cr(VI) was found to behigh with the increase of pH value (2 to 4) and to abruptlyfall down when pH was increased to 4 (Figure 2) At moreacidic conditions HCr

2O7

minus and Cr2O7

2minus dimers becomethe dominant Cr(VI) form and the pKa1 and pKa2 values ofthese ions are 074 and 649 respectively [24 25] In aqueoussolutions having a lower pH the dichromate will be presentprimarily in its protonated form that is HCr

2O7

minus and it


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7

Reco

very

()

pH

Cr(VI)Pb(II)

Figure 2 Influence of sample pH on DLLME at 40mL initialvolume of water samples 025 APDC 100 120583L CCl

4

100mL ofethanol and 001mgL Cr(VI)Pb(II)

50

60

70

80

90

100

110

0 025 05 075 1 125 15 175 2

Reco

very

()

Concentration ()

Cr(VI)Pb(II)

Figure 3 Influence of APDC concentration on DLLME for Cr(VI)and Pb(II) at 40mL initial volume of water samples pH 20 and010mgL Cr(VI)Pb(II)

was observed in most of studies that the APDCmostly formscomplexes with HCr

2O7

minus ions [24 25] In case of Pb(II) theobtained results show that the recoveries percentage of Pb(II)is high in the pH 30 (Figure 2) Therefore the pH 30 wasselected for simultaneous optimum recoveries of Cr(VI) andPb(II)

The effect of the APDC amount in the range of 005ndash2 (vv) for the simultaneous preconcentration of Cr(VI)and Pb(II) was studied In this case the enrichment factorincreased up to 01 (vv) APDC reaching a plateau whichis considered asmaximum extraction (Figure 3) For simulta-neously determination of Cr(VI) and Pb(II) was recorded inthe range of 010ndash200 (mv) On the behalf of resulted data025 (mv) APDC solution in water was adopted for furtherstudy The 025 (vv) APDC was chosen as the optimalamount for the Cr(VI) and Pb(II) to prevent any interference

36 Effect of the Coexisting Ions In order to assess thefeasibility of DLLME for analytical applications the effect of

Table 1 Tolerable levels of concomitant ions for the extraction of10120583gL Cr(VI) and Pb(II) (119873 = 4)

Ions Tolerable levels (mgL)Cr(VI) Pb(II)

Na+ Clminus 1000Li+ K+ Ca2+ Mg2+ 250SO4

minus2 NO3

minus 100Cu(II) Fe(II) Se(II) As(III) Co(II)Hg(II) Mn(II) Cr(III) Ni(II) Al(III)Zn(II)

50

Table 2 The results for tests of additionrecovery for Cr(VI) byDLLME in industrial wastewater samples (119899 = 6)

Amount added(120583gL)

Found valuesMean plusmn SD(120583gL)

Recoverya RSD

Cr(VI)

mdash 125 plusmn 24 mdash mdash10 247 plusmn 03 1100 plusmn 15 1425 407 plusmn 07 1080 plusmn 18 1750 614 plusmn 34 985 plusmn 33 34

Pb(II)


aRecovery = (119862after spiked(119862intial + 119862spiked)) times 100

some foreign ions which interfere with Cr(VI) and Pb(II)ion andor often accompany analyte ions in various realenvironmental samples was investigated with the optimizedconditions (Table 1) It is a general rule for analytical chem-istry that anymatrixwas considered to interfere if the resultedFAAS signal of understudied analyte was varied plusmn50 Therecoveries of Cr(VI) and Pb(II) were almost quantitativein the presence of an excessive amount of the possibleinterfering cations and anions (Table 1)

37 Analytical Figure of Merits The analytical characteristicsof the proposed procedure were calculated under the opti-mized conditionsThese characteristics were calculated usingthe values of the signals for analytical curve The calibrationand standard addition graphs were obtained for Cr(VI) andPb(II) determined by microsample injection system flameatomic absorption spectrometry (MIS-FAAS) The linearrange of the calibration graphs obtained in the concentrationrange from 1 to 10 120583gL for Cr(VI) and Pb(II) The limitof detection (LOD) and limit of quantification (LOQ) werecalculated as 3 times 119878

119887119898 and 10 times 119878

119887119898 respectively where

119878119887is the standard deviation of the blank (119899 = 10) and119898 is slope of the linear section of calibration graph TheLODs of Cr(VI) and Pb(II) were found to be 0037 and0054 120583gL whereas LOQs were 0124 and 0182 120583g Lminus1respectively The calibration curve of Cr(VI) and Pb(II) forover this interval was determined to be 119860 = 210 times 10minus2 times[Cr(VI)] + 600 times 10minus5 and 119860 = 240 times 10minus2 times [Pb(II)] +


Table 3 Comparative data of analytical characteristics of the literature reported methods and proposed method

Analyte(s) Analyticaltechnique Extraction phase

Extractiontime(min)

Enrichmentfactor

LOD(120583gL) RSD () Ref

Cr(VI) FAASEthyl xanthatecomplex ontonaphthalene

15 100 0500 31 [25]

Cr(VI) CE-FAAS Dy2O3 aqueous solution 20 100 0780 mdash [26]

Cr(VI) UPAILDLLME-ETAAS APDC[Hmim][PF6] 5-6 300 007 92 [22]

Cr(VI) DLLME-UV-Visspectrophotometry DICToluene mdash mdash 300 lt50 [27]

Cr(VI) DLLME-ETAAS APDCCCl4 mdash 171 000596 302 [28]Cr(VI)Cr(T) DLLME-FAAS APDC + EDTA

CCl4008 275

262007008

2026 [29]

Cr(VI) DLLME-ETAAS APDC +([C8MIm][NTf2])

mdash 300 0002 [30]

Cr(VI) DLLME-MIS-FAAS APDCCCl4 008ndash016 400 0037 lt40 Current

study

Pb(II) CP-FAAS 5-Chloro-2-hydroxyaniline-Cu(II) 10 50 272 lt50 [31]

Pb(II) MF-FAAS Cellulose nitrateHNO3 mdash 60 030 lt10 [32]Pb(II) SDME-ETAAS DDTPCHCl3 7 52 020 lt40 [33]

Pb(II) IL-SDME-ETAAS 5-Br-PADAPCYPHOSIL 101 15 32 00032 49 [34]

Pb(II) IL-SDME-ETAAS APDC[C4MIM][PF6] 7 76 0015 52 [35]Pb(II) DLLME-FAAS DDTPCCl4 008 450 050 38 [36]Pb(II) DLLME-GFAAS DDTPCCl4 lt3 150 002 25 [37]Pb(II) DLLME-GFAAS PMBPCCl4 5 78 00039 32 [38]

Pb(II) DLLME-MIS-FAAS APDCCCl4 008ndash016 400 0054 lt50 Current

studyAmmonium pyrrolidine dithiocarbamate (APDC) 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) 1-butyl-3-methylimidazolium hexafluo-rophosphate [C4MIM][PF6] charge coupled device (CCD) coprecipitation flame atomic absorption spectroscopy (CE-FAAS) OO-diethyldithiophosphate(DDTP) methylindocarbocyanine (DIC) 15-diphenylcarbazide (DPC) 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]) electrothermalatomic absorption spectroscopy (ETAAS) graphite furnace atomic absorption spectroscopy (GFAAS) inductively coupled plasma-optical emissionspectrometry (ICP-OES) pyrrolidine dithiocarbamate (PDC) 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) single drop microextraction (SDME)sequential injection analysis (SIA) tetradecyl(trihexyl)phosphonium chloride (CYPHOS IL 101) ultrasonic probe-assisted ionic liquid dispersive liquid-liquidmicroextraction (UPAILDLLME) 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C8MIm][NTf2])

100 times 10minus3 respectively where 119860 is the analytical signalmeasured as absorbance and [Cr(VI)] and [Pb(II)] are theconcentrations of chromium and lead respectively (120583gL)The correlation coefficients (119903) were 0999 and 0998 forCr(VI) and Pb(II) respectively The RSD of both methodswas evaluated with 4000mL from the solution containingthe 001120583gL Cr(VI)Pb(II) and was achieved lt5 (119899 = 4)The enrichment factor (EF) was calculated by the ratio ofCr(VI)Pb(II) concentration in sediment phase and initialconcentration in original solution Finally the enrichmentfactor 400 was obtained for simultaneous preconcentrationof Cr(VI) and Pb(II)

The reliability of the simplest calibration against aqueousstandard solutions for DLLME was verified by means ofspiking experiments at three concentration levels of Cr(VI)and Pb(II) in the range of 10 to 50120583gL with the maximumrecovery percentage (985ndash110) as summarized in Table 2

A good agreement was obtained between the added andmeasured analyte concentrations (119875 lt 0001)

38 Comparison of the Proposed Methods with the OtherLiterature Reported Method Comparison of the proposedmethod with other approaches reported in the literature forpreconcentration and determination of Cr(VI) and Pb(II)is represented in Table 3 The results showed that theextraction time for proposed DLLME is short (5ndash10 sec)The enrichment factors LODs and RSDs of DLLME arecomparable with those reported in the literature [22 25ndash37] The proposed methods (DLLME and CECP) coupledwith MIS-FAAS are simple most sensitive and selectiveTherefore these methods could successfully be applied tothe monitoring of trace amounts of chromium species inenvironmental biological and soil samples


Table 4 Analytical results of Cr(VI) and Pb(II) (120583gL) in drinkingwater and industrial effluents (Denizli Turkey)

Origin of water (no of samples) Cr(VI) Pb(II)Groundwater (119899 = 6) 37 plusmn 18 326 plusmn 16

Tap water (119899 = 6) 26 plusmn 05 104 plusmn 21

Untreated industrial effluent (119899 = 4) 233 plusmn 53 917 plusmn 18

Treated industrial effluent (119899 = 4) 96 plusmn 45 703 plusmn 12

39 Application to Real Samples The simultaneous precon-centration of Cr(VI) and Pb(II) in tap water groundwaterand industrial effluents before and after treatmentwas studiedusing DLLME (Table 4) Cr(VI) and Pb(II) contents intapwater and groundwater varied in the ranges 00 to 32 and00 to 60 and (80 to 130 and 310 to 340 120583gL respectivelyThe Cr(VI) and Pb(II) contents in tap water samples werefallen within the WHO maximum contaminant level 50 and10 120583gL respectively The Cr(VI) and Pb(II) contents werefound higher in groundwater as compared to tap waterbecause the natural abundance of geochemicals containingCr(VI) and Pb(II) The high contents of Cr(VI) and Pb(II)in groundwater may cause hematological damage braindamage anemia kidney malfunctioning infections of skinand gastrointestinal tract and carcinoma of the lung [38 39]But Cr(VI) in ground water of Denizli did not exceed WHOregulated values (500120583gL) of Cr(VI) for drinking waterThus both understudied waters (tapwater and groundwater)have safe levels of Cr(VI) for local community as naturaldrinking water sources But Pb(II) in groundwater was foundto be high which is not suitable for drinking as well ascooking

The Cr(VI) and Pb(II) in the tannery effluent samplesbefore and after treatmentwere also determined by developedpreconcentration method as shown in Table 4 The Cr(VI)and Pb(II) were observed in excess amount in untreatedindustrial water (Table 4) because of human activities espe-cially through the production of wastewater in electroplatingtanning textile and dyestuff industries present in industrialzone However the Denizli municipality has a well-organizedbiological treatment plant based upon systemof classical acti-vated sludge for the recycling of industrial and municipalitywastewater The industrial samples after treatment have lessamount of Cr(VI) and Pb(II) removal percentage of Cr(VI)and Pb(II) by biological treatment plant was 30 to 50 asshown in Table 4

4 Conclusion

The DLLME coupled with MIS-FAAS was developed forsimultaneous ultratrace level of Cr(VI) and Pb(II) determi-nation in drinking water and industrial effluent before andafter treatment Proposed method proved to be fast simpleinexpensive and reproducible for the ultratrace level ofCr(VI) and Pb(II) with high enrichment factor (400) In thiswork the use of handmade microsample injection systemsfor ultratrace level determination of Cr(VI) and Pb(II) offersseveral advantages including low cost reusable and required

less volume of sample with high recoveries percentage ascompared to continuous flow FAAS

Acknowledgments

The authors gratefully acknowledge the Scientific and Tech-nical Research Council of Turkey (TUBITAK) and AnalyticalSection of Chemistry Department Pamukkale UniversityDenizli for financial assistance and laboratory and instru-mental facilities for postdoctoral Studies Moreover it wouldbe acknowledged to Nilgun ELYAS laboratory supervisor ofDenizli Environment Quality Laboratory (DENCEV) andresearch assistant of Chemistry Department of PamukkaleUniversity for sampling assistance

References

[1] F Shah T G Kazi H I Afridi et al ldquoThe influence ofenvironmental exposure on lead concentrations in scalp hair ofchildren in Pakistanrdquo Ecotoxicology and Environmental Safetyvol 74 no 4 pp 727ndash732 2011

[2] P Chooto P Wararatananurak and C Innuphat ldquoDetermina-tion of trace levels of Pb(II) in tap water by anodic strippingvoltammetry with boron-doped diamond electroderdquo ScienceA-sia vol 36 no 2 pp 150ndash156 2010

[3] Y Wang S Gao X Zang J Li and J Ma ldquoGraphene-basedsolid-phase extraction combined with flame atomic absorptionspectrometry for a sensitive determination of trace amounts oflead in environmental water and vegetable samplesrdquo AnalyticaChimica Acta vol 716 pp 112ndash118 2012

[4] L Elci U Divrikli A Akdogan A Hol A Cetin and MSoylak ldquoSelective extraction of chromium(VI) using a leachingprocedure with sodium carbonate from some plant leaves soiland sediment samplesrdquo Journal of HazardousMaterials vol 173no 1ndash3 pp 778ndash782 2010

[5] M Korolczuk andA Stępniowska ldquoDetermination of Cr(VI) inthe presence of high excess of a Cr(III) by adsorptive strippingvoltammetryrdquo Talanta vol 88 pp 427ndash431 2012

[6] A N Anthemidis and S-J V Koussoroplis ldquoDetermination ofchromium(VI) and lead in water samples by on-line sorptionpreconcentration coupled with flame atomic absorption spec-trometry using a PCTFE-beads packed columnrdquo Talanta vol71 no 4 pp 1728ndash1733 2007

[7] T Minami Y Sohrin and J Ueda ldquoDetermination ofchromium copper and lead in river water by graphite-furnaceatomic absorption spectrometry after coprecipitation with ter-bium hydroxiderdquo Analytical Sciences vol 21 no 12 pp 1519ndash1521 2005

[8] S Baytak andA R Turker ldquoDetermination of lead and nickel inenvironmental samples by flame atomic absorption spectrome-try after column solid-phase extraction onAmbersorb-572 withEDTArdquo Journal of Hazardous Materials vol 129 no 1ndash3 pp130ndash136 2006

[9] G Doner and A Ege ldquoDetermination of copper cadmium andlead in seawater and mineral water by flame atomic absorptionspectrometry after coprecipitation with aluminum hydroxiderdquoAnalytica Chimica Acta vol 547 no 1 pp 14ndash17 2005

[10] K Kiran K S Kumar B Prasad K Suvardhan R B Lekkalaand K Janardhanam ldquoSpeciation determination of chromi-um(III) and (VI) using preconcentration cloud point extraction


with flame atomic absorption spectrometry (FAAS)rdquo Journal ofHazardous Materials vol 150 no 3 pp 582ndash586 2008

[11] P Liang Q Ding and Y Liu ldquoSpeciation of chromium byselective separation and preconcentration of Cr(III) on animmobilized nanometer titanium dioxide microcolumnrdquo Jour-nal of Separation Science vol 29 no 2 pp 242ndash247 2006

[12] A Beni R Karosi and J Posta ldquoSpeciation of hexavalentchromium in waters by liquid-liquid extraction and GFAASdeterminationrdquo Microchemical Journal vol 85 no 1 pp 103ndash108 2007

[13] H FMaltez andECarasek ldquoChromium speciation andprecon-centration using zirconium(IV) and zirconium(IV) phosphatechemically immobilized onto silica gel surface using a flowsystem and FAASrdquo Talanta vol 65 no 2 pp 537ndash542 2005

[14] S Pramanik S Dey and P Chattopadhyay ldquoA new chelatingresin containing azophenolcarboxylate functionality synthesischaracterization and application to chromium speciation inwastewaterrdquo Analytica Chimica Acta vol 584 no 2 pp 469ndash476 2007

[15] J Nakajima Y Hirano and K Oguma ldquoDetermination oflead in seawater by flow-injection on-line preconcentration-electrothermal atomic absorption spectrometry after coprecip-itation with iron(III) hydroxiderdquo Analytical Sciences vol 19 no4 pp 585ndash588 2003

[16] J Guo Y Chai R Yuan Z Song and Z Zou ldquoLead (II)carbon paste electrode based on derivatized multi-walled car-bon nanotubes application to lead content determination inenvironmental samplesrdquo Sensors and Actuators B vol 155 no2 pp 639ndash645 2011

[17] H A Panahi J Morshedian N Mehmandost E Moniri and IY Galaev ldquoGrafting of poly[1-(NN-bis-carboxymethyl)amino-3-allylglycerol-co-dimethylacrylamide] copolymer onto silice-ous support for preconcentration and determination of lead(II) in human plasma and environmental samplesrdquo Journal ofChromatography A vol 1217 no 32 pp 5165ndash5172 2010

[18] F Pena-Pereira I Lavilla and C Bendicho ldquoMiniaturized pre-concentration methods based on liquid-liquid extraction andtheir application in inorganic ultratrace analysis and speciationa reviewrdquo Spectrochimica Acta B vol 64 no 1 pp 1ndash15 2009

[19] H Sereshti V Khojeh and S Samadi ldquoOptimization of dis-persive liquid-liquid microextraction coupled with inductivelycoupled plasma-optical emission spectrometry with the aid ofexperimental design for simultaneous determination of heavymetals in natural watersrdquo Talanta vol 83 no 3 pp 885ndash8902011

[20] V Andruch C C Acebal J Skrlıkova et al ldquoAutomated on-linedispersive liquid-liquid microextraction based on a sequentialinjection systemrdquoMicrochemical Journal vol 100 no 1 pp 77ndash82 2012

[21] A N Anthemidis and M Miro ldquoRecent developments inflow injectionsequential injection liquid-liquid extraction foratomic spectrometric determination of metals and metalloidsrdquoApplied Spectroscopy Reviews vol 44 no 2 pp 140ndash167 2009

[22] W Chen G Zhong Z Zhou P Wu and X Hou ldquoAutomationof liquid-liquid extraction-spectrophotometry using prolongedpseudo-liquid drops and handheld CCD for speciation ofCr(VI) and Cr(III) in water samplesrdquo Analytical Sciences vol21 no 10 pp 1189ndash1193 2005

[23] J L Manzoori M Amjadi and J Abulhassani ldquoUltra-tracedetermination of lead in water and food samples by usingionic liquid-based single drop microextraction-electrothermal

atomic absorption spectrometryrdquo Analytica Chimica Acta vol644 no 1-2 pp 48ndash52 2009

[24] J A Baig A Hol A Akdogana et al ldquoA novel strategyfor chromium speciation at ultra-trace level by microsampleinjection flame atomic absorption spectrophotometryrdquo Journalof Analytical Atomic Spectrometry vol 27 pp 1509ndash1517 2012

[25] P G Krishna J M Gladis U Rambabu T P Rao and G R KNaidu ldquoPreconcentrative separation of chromium(VI) speciesfrom chromium(III) by coprecipitation of its ethyl xanthatecomplex onto naphthalenerdquo Talanta vol 63 no 3 pp 541ndash5462004

[26] A Karatepe E Korkmaz M Soylak and L Elci ldquoDevelopmentof a coprecipitation system for the speciationpreconcentrationof chromium in tapwatersrdquo Journal of HazardousMaterials vol173 no 1ndash3 pp 433ndash437 2010

[27] M Alexovi I S Balogh J Skrlikova and V Andruch ldquoAdispersive liquid-liquid micro-extraction procedure for UV-Visspectrophotometric determination of chromium (VI) in watersamplesrdquo Analytical Methods vol 4 pp 1410ndash1414 2012

[28] M S Tehrani P A Azar S W Husain and F Shafaei ldquoDisper-sive liquid-liquid microextraction of Cr(VI) in water and hairsamples by electrothermal atomic absorption spectrometryrdquoAsian Journal of Chemistry vol 22 no 8 pp 6302ndash6310 2010

[29] P Hemmatkhah A Bidari S Jafarvand M R M Hosseiniand Y Assadi ldquoSpeciation of chromium in water samples usingdispersive liquid-liquid microextraction and flame atomicabsorption spectrometryrdquo Microchimica Acta vol 166 no 1-2pp 69ndash75 2009

[30] I Lopez-Garcıa Y Vicente-Martınez and M Hernandez-Cordoba ldquoDetermination of very low amounts of chromi-um(III) and (VI) using dispersive liquid-liquidmicroextractionby in situ formation of an ionic liquid followed by electrother-mal atomic absorption spectrometryrdquo Journal of AnalyticalAtomic Spectrometry vol 27 pp 874ndash880 2012

[31] M Tuzen D Citak and M Soylak ldquo5-chloro-2-hydroxyani-line-copper(II) coprecipitation system for preconcentrationand separation of lead(II) and chromium(III) at trace levelsrdquoJournal of HazardousMaterials vol 158 no 1 pp 137ndash141 2008

[32] U Divrikli A A Kartal M Soylak and L Elci ldquoPreconcent-ration of Pb(II) Cr(III) Cu(II) Ni(II) and Cd(II) ions in envi-ronmental samples by membrane filtration prior to their flameatomic absorption spectrometric determinationsrdquo Journal ofHazardous Materials vol 145 no 3 pp 459ndash464 2007

[33] H F Maltez D L G Borges E Carasek B Welz and A J Cur-tius ldquoSingle drop micro-extraction with OO-diethyl dithio-phosphate for the determination of lead by electrothermalatomic absorption spectrometryrdquo Talanta vol 74 no 4 pp800ndash805 2008

[34] E M Martinis P Berton J C Altamirano U Hakala andR G Wuilloud ldquoTetradecyl(trihexyl)phosphonium chlorideionic liquid single-drop microextraction for electrothermalatomic absorption spectrometric determination of lead in watersamplesrdquo Talanta vol 80 no 5 pp 2034ndash2040 2010

[35] J L Manzoori M Amjadi and J Abulhassani ldquoUltra-tracedetermination of lead in water and food samples by usingionic liquid-based single drop microextraction-electrothermalatomic absorption spectrometryrdquo Analytica Chimica Acta vol644 no 1-2 pp 48ndash52 2009

[36] M T Naseri P HemmatkhahM RMHosseini and Y AssadildquoCombination of dispersive liquid-liquid microextraction withflame atomic absorption spectrometry using microsample


introduction for determination of lead in water samplesrdquoAnalytica Chimica Acta vol 610 no 1 pp 135ndash141 2008

[37] M T Naseri M R M Hosseini Y Assadi and A Kiani ldquoRapiddetermination of lead in water samples by dispersive liquid-liquid microextraction coupled with electrothermal atomicabsorption spectrometryrdquo Talanta vol 75 no 1 pp 56ndash622008

[38] P Liang and H Sang ldquoDetermination of trace lead in biologicaland water samples with dispersive liquid-liquid microextrac-tion preconcentrationrdquo Analytical Biochemistry vol 380 no 1pp 21ndash25 2008

[39] G D Matos E B dos Reis A C S Costa and S L C FerreiraldquoSpeciation of chromium in river water samples contaminatedwith leather effluents by flame atomic absorption spectrometryafter separationpreconcentration by cloud point extractionrdquoMicrochemical Journal vol 92 no 2 pp 135ndash139 2009

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

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 ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


andor separation step prior the final measurement is usuallyrequired for significant precise sensitive and accurate deter-mination in order to bring the analyte concentration into thedynamic range of the detector or to isolate the analyte fromthe desirable matrix constituents [3 4 10 11]

The preconcentration methods like solvent extractionion exchange adsorption and coprecipitation were fre-quently used for trace level analysis of Cr(VI) and Pb(II)[12ndash17] Liquid-liquid extraction based on transfer of ana-lyte from the aqueous sample to a water-immiscible sol-vent is being widely employed for sample preparation [18]But these methods are time consuming needed significantchemical additives large secondary wastes along procedureand required complex equipment Miniaturization of liquidextraction methods can be achieved by a drastic reduction ofthe extractant phase volume three new methodologies havebeen developed that is single-drop microextraction hollowfibre liquid-phase microextraction and dispersive liquid-liquid microextraction [19] Among them dispersive liquid-liquid microextraction (DLLME) is effectively useful for theseparation and pre-concentration of organic and inorganiccontaminants in environmental samples in a single step [1820 21]

For the current study a new approach has been designedfor the simultaneous and selective determination of Cr(VI)and Pb(II) at trace level in environmental samples based onDLLME Ammonium pyrrolidine dithiocarbamate (APDC)has been used as a selective chelating agent for Cr(VI)and Pb(II) [22 23] The applicability of DLLME coupledwith microsample injection system flame atomic absorptionspectroscopy for Cr(VI) and Pb(II) preconcentration andseparation was adopted as evaluated in our previous work[24] The influence of the different analytical parameters forboth methods was investigated in detailed The proposedmethod was applied to tap water groundwater and industrialeffluent before and after treatment for evaluation of Cr(VI)and Pb(II)

2 Experimental

21 Sampling Six samples of each type of drinking water(tapwater and groundwater samples) were collected in Nov-ember 2011 from different sampling sites of Denizli Tur-key (situated between the coordinates 37∘4610158404810158401015840N and29∘0410158404810158401015840E in Aegean region) Whereas the industrial efflu-ent before and after treatment (six samples of each) fromwell organized industrial zone of Denizli with the assistanceof Denizli Environment Quality Laboratory (DENCEV)Theproposed methods (details are given below) were performedon the same week of sampling So the sample storage was notrequired

22 Reagents All solutions were prepared using ultrapurewater (resistivity 182MΩcm) obtained with a reverseosmosis system (Human Corporation Seoul Republic ofKorea) Standard solutions of Cr(VI) and Pb(II) were pre-pared by dilution of 1000 ppm certified standard solutionsFluka (Buchs Switzerland)Working standard solutions were

freshly prepared by appropriate dilution of the stock standardsolution Ammonium pyrrolidine dithiocarbamate (APDCFluka) was used as the chelating agent to form the hydropho-bic metal complexes A 5 (wv) of APDC solution wasprepared by dissolving suitable amount of APDC in ultrapurewater Buffer of pH 1-2 was prepared by adding an appropriateamount of hydrochloric acid Merck (Darmstadt Germany)and potassium chloride and buffer of pH 3ndash6 was preparedby adding an appropriate amount of acetic acid (Merck) andsodium acetate

23 Apparatus An atomic absorption spectrometer (Perki-nElmer AAnalyst 200) equipped with a chromium hollowcathode lamp an air-acetylene flame atomizer and hand-made microinjection system was used for determinationsThe wavelength lamp current and spectral bandwidth usedwere 3579 nm 25mA and 07 nm respectively The pHmeasurements were carried out with a pHmeter (WTW-pH-meter-720) A centrifuge (Hettich Centrifuge Germany) wasused to accelerate the phase separation processMicroinjector(Hamilton Switzerland) was used for sediment phase separa-tion

24 Preparation of Handmade Microsample Injection System(MIS) In routine practice a sample volume of 2ndash4mL isrequired for a single element determination by FAAS How-ever a small volume was obtained by each preconcentrationmethod (lt05mL) whereas there is need for high dilutionTo resolve this problem our group have made a microsampleinjection system (MIS) coupled to the nebulizer needleusing a PTFE capillary tube (length of 12 cm) attached withyellow micropipette tip (capacity 20ndash200120583L) as reported inour previous work [24] For simultaneous determination ofCr(VI) and Pb(II) 100mL was used for each analysis

25 Dispersive Liquid-Liquid Microextraction The Cr(VI)and Pb(II) were determined by DLLME using a complexingreagent (APDC) and resulted complex was enriched intoextraction solvent through disperser solvent To optimizeDLLME four replicate of sub-samples (40mL) of standardsolution containing 10 120583g Lminus1 Cr(VI) and Pb(II) in PTFEtubes (50mL in capacity) The pH was adjusted with appro-priate buffer solution in the range of 1ndash6 Then added 005ndash2 (wv) APDC and 1ndash4mL ethanol containing 100ndash400120583Ltetrachloride carbon was rapidly injected into the aqueoussolution with a 2550mL syringe As a result a turbid phaseimmediately was formed The acquired solution was cen-trifuged at 3000 rpm for 5min The CCl

4as sediment phase

was separated in the range of 80ndash90120583L by microinjector into2mL glass vial The residual phase was vaporized to drynessby electrical hot plate and dissolved in 01mL of 01molLHNO

3 The final solution was determined by MIS-FAAS

26 Determination of Cr(VI) and Pb(II) in Water and Indus-trial Effluents 40mL of replicate four subsamples of tapwater groundwater and industrial effluent were filtered withordinary filter papers to removed unsalable matrices andtaken in PTFE tubes (50mL in capacity) Then treated with


050

100150200250300350400450

0 1 2 3 4 5

Enric

hmen

t fac

tor

Volume (mL)








3andCCl



4and CHCl












investigations


3CN CH

3CH2OH and CH

3OH) were tested




3CH2OH













2O7

minus and Cr2O7


2O7

minus and it


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7

Reco

very

()

pH

Cr(VI)Pb(II)


4


50

60

70

80

90

100

110

0 025 05 075 1 125 15 175 2

Reco

very

()

Concentration ()

Cr(VI)Pb(II)



2O7







minus2 NO3


50




Recoverya RSD

Cr(VI)


Pb(II)





119887119898 and 10 times 119878






Extractiontime(min)

Enrichmentfactor



15 100 0500 31 [25]





CCl4008 275

262007008

2026 [29]


mdash 300 0002 [30]


study



















4 Conclusion



Acknowledgments


References






















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


050

100150200250300350400450

0 1 2 3 4 5

Enric

hmen

t fac

tor

Volume (mL)








3andCCl



4and CHCl












investigations


3CN CH

3CH2OH and CH

3OH) were tested




3CH2OH













2O7

minus and Cr2O7


2O7

minus and it


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7

Reco

very

()

pH

Cr(VI)Pb(II)


4


50

60

70

80

90

100

110

0 025 05 075 1 125 15 175 2

Reco

very

()

Concentration ()

Cr(VI)Pb(II)



2O7







minus2 NO3


50




Recoverya RSD

Cr(VI)


Pb(II)





119887119898 and 10 times 119878






Extractiontime(min)

Enrichmentfactor



15 100 0500 31 [25]





CCl4008 275

262007008

2026 [29]


mdash 300 0002 [30]


study



















4 Conclusion



Acknowledgments


References






















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0

20

40

60

80

100

120

0 1 2 3 4 5 6 7

Reco

very

()

pH

Cr(VI)Pb(II)


4


50

60

70

80

90

100

110

0 025 05 075 1 125 15 175 2

Reco

very

()

Concentration ()

Cr(VI)Pb(II)



2O7







minus2 NO3


50




Recoverya RSD

Cr(VI)


Pb(II)





119887119898 and 10 times 119878






Extractiontime(min)

Enrichmentfactor



15 100 0500 31 [25]





CCl4008 275

262007008

2026 [29]


mdash 300 0002 [30]


study



















4 Conclusion



Acknowledgments


References






















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Extractiontime(min)

Enrichmentfactor



15 100 0500 31 [25]





CCl4008 275

262007008

2026 [29]


mdash 300 0002 [30]


study



















4 Conclusion



Acknowledgments


References






















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of









4 Conclusion



Acknowledgments


References






















































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















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

Research Article Ultratrace Determination of Cr(VI) and Pb