Preconcentration and separation of nickel, copper and cobalt using solid phase extraction and their determination in some real samples

A solid phase extraction method has been developed to separate and concentrate trace amounts of nickel, cobalt and copper ions from aqueous samples for the measurement by flame atomic absorption spectrometry. By the passage of aqueous samples through activated carbon modified by dithioxamide (rubeanic acid) (DTO), Ni2+, Cu2+ and Co2+ ions adsorb quantitatively. The recoveries of analytes at pH 5.5 with 500 mg solid phase were greater than 95% without interference from alkaline, earth alkaline and some metal ions. The enrichment factor was 330. The detection limits by three sigma were 0.50 microg L(-1) for copper, 0.75 microg L(-1) for nickel and 0.80 microg L(-1) for cobalt. The loading capacity was 0.56 mg g(-1) for Ni2+, 0.50 mg g(-1) for Cu2+ and 0.47 mg g(-1) for Co2+. The presented procedure was applied to the determination of analytes in tap, river and sea waters, vegetable, soil and blood samples with successfully results (recoveries greater than 95%, R.S.D. lower than 2% for n=3).     

A biosorption system for metal ions on Penicillium italicum-loaded on Sepabeads SP 70 prior to flame atomic absorption spectrometric determinations

A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the microg L(-1) levels on Penicillium italicum-loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L(-1) HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3s, n=21) for analytes were in the range of 0.41microg L(-1) (cadmium) and 1.60microg L(-1) (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples.     

The determination of some heavy metals in food samples by flame atomic absorption spectrometry after their separation-preconcentration on bis salicyl aldehyde, 1,3 propan diimine (BSPDI) loaded on activated carbon

A sensitive and simple method for the simultaneous preconcentration of Cr3+, Fe3+, Cu2+, Ni2+, Co2+ and Zn2+ in real samples has been reported. The method is based on the adsorption of analytes on bis salicyl aldehyde, 1,3 propan diimine (BSPDI) loaded on activated carbon. The adsorbed metals on modified activated carbon were eluted using 8 mL of 2 mol L(-1) nitric acid in acetone or 10 mL of 4 mol L(-1) HNO3. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally quantitative. The method has been successfully applied for these metals content evaluation in some food samples.     

Gadolinium hydroxide coprecipitation system for the separation-preconcentration of some heavy metals

A simple and new procedure for the determination of trace amounts of lead(II), cobalt(II), manganese(II) and copper(II) is described, that combines atomic absorption spectrometry-gadolinium hydroxide coprecipitation. One milliliter of 1% gadolinium(III) solution was added to each sample; the pH was then adjusted to 11 in order to collect trace heavy metals on gadolinium(III) hydroxide. The precipitate was separated by centrifugation and dissolved in 1 mL of 1 mol L(-1) HNO3. The influences of analytical parameters including amount of gadolinium(III), sample volume, etc. were investigated on the recoveries of analyte ions. The effects of concomitant ions were also examined. The recoveries of the analyte ions were greater than 95. The detection limits for the analyte elements based on 3 sigma (n=20) were in the range of 0.52-12.0 microg L(-1). The method was applied to the determination of analytes in real samples and good results were obtained (relative standard deviations <10%, recoveries >95%).     

Diaion SP-850 resin as a new solid phase extractor for preconcentration-separation of trace metal ions in environmental samples

A solid phase extraction method was developed for the preconcentration and separation of trace amounts of chromium, manganese, iron, cobalt, copper, cadmium and lead from environmental samples by complexation with alpha-benzoin oxime followed by adsorption onto Diaion SP-850-solid phase extraction column. One molar per liter HNO(3) was used as eluent. The recoveries of analytes at pH 8.0 with 700 mg of resin were greater than 95% without interference from alkaline, earth alkaline and some metal ions. The detection limits by three sigma for analyte ions were 0.65 microg l(-1) for Cr(III), 0.42 microg l(-1) for Mn(II), 0.28 microg l(-1) for Fe(III), 0.73 microg l(-1) for Co(II), 0.30 microg l(-1) for Cu(II), 0.47 microg l(-1) for Cd(II) and 0.50 microg l(-1) for Pb(II). The validation of the procedure was performed by the analysis of the certified standard reference materials. The presented procedure was applied to the determination of analytes in tap, river and sea waters, rice, wheat, canned tomato and coal samples with successfully results (recoveries greater than 95%, R.S.D.'s lower than 8%).     

Coprecipitation of Ni(2+), Cd(2+) and Pb(2+) for preconcentration in environmental samples prior to flame atomic absorption spectrometric determinations

A coprecipitation procedure has been presented prior to flame atomic absorption spectrometric determination of nickel, cadmium and lead ions in environmental samples. Analyte ions were coprecipitated by using copper hydroxide precipitate. The influences of some analytical parameters like amounts of copper, sample volume, etc., on the recoveries of the analytes were investigated. The interference of other ions was negligible. Under the optimized conditions, the detection limits (3 sigma, n=15) of lead(II), nickel(II) and cadmium(II) were 7.0, 3.0 and 2.0 microg/L, respectively. The proposed method has been successfully applied for the determination of traces of Ni, Cd and Pb in environmental samples like tap water.     

Dysprosium(III) hydroxide coprecipitation system for the separation and preconcentration of heavy metal contents of table salts and natural waters

A procedure for the determination of trace amounts of Pb(II), Cu(II), Ni(II), Co(II), Cd(II) and Mn(II) is described, that combines atomic absorption spectrometry-dysprosium hydroxide coprecipitation. The influences of analytical parameters including amount of dysprosium(III), centrifugation time, sample volume, etc. were investigated on the recoveries of analyte ions. The effects of concomitant ions were also examined. The recoveries of the analyte ions were in the range of 95.00-104.00%. The detection limits corresponding to three times the standard deviation of the blank for the analytes were in the range of 14.1-25.3 microg/L. The method was applied to the determination of lead, copper, nickel, cobalt, cadmium and manganese ions in natural waters and table salts good results were obtained (relative standard deviations <10%, recoveries >95%).     

Bacillus thuringiensis var. israelensis immobilized on Chromosorb 101: a new solid phase extractant for preconcentration of heavy metal ions in environmental samples

Bacillus thuringiensis var. israelensis immobilized on Chromosorb 101 that is a new solid phase extractor has been presented at this work for the preconcentration and separation of cadmium(II), lead(II), manganese(II), chromium(III), nickel(II) and cobalt(II) in environmental samples. The analytical parameters including pH of aqueous solutions, sample volume, eluent types, etc. were investigated for the quantitative recoveries of the analytes. The influences of the some metal ions as concomitant were investigated. Under the optimized conditions, the detection limits by 3sigma for analyte ions were in the range of 0.37-2.85 microg L(-1). The accuracy of the developed procedure was confirmed by IAEA 336 Lichen and NIST SRM 1573a Tomato leaves certified reference materials. The method was also applied successfully to the determination of analytes in microwave digested red wine, rice and canned fish samples and sea water, spring water and urine samples.     

Solid-phase extraction of copper, iron and zinc ions on Bacillus thuringiensis israelensis loaded on Dowex optipore V-493

Bacillus thuringiensis israelensis loaded on Dowex optipore V-493 as new adsorbent for the separation-preconcentration of heavy metal ions has been proposed. The analytical conditions for the quantitative recoveries of copper(II), iron(III) and zinc(II) including pH, amounts of adsorbent, sample volume, etc. were investigated. The influences of alkaline and earth alkaline ions were also reported. The recovery values for the analytes are generally higher than 95%. The preconcentration factor was 37. The limit of detections of the analyte ions (k=3, N=21) were 1.14 microgL(-1) for copper, 2.01 microgL(-1) for iron and 0.14 microgL(-1) for zinc. The relative standard deviations of the determinations were found to be lower than 9%. The procedure was validated by analyzing copper, iron and zinc contents in two certified reference materials, NRCC-SLRS-4 Riverine water and NIST SRM 1515 Apple leaves. Agreements between the obtained results and the certified values were achieved. The developed preconcentration method was applied in the flame atomic absorption spectrometric determination of copper, iron and zinc in several samples including a multivitamin-multimineral tablet, dialysis solutions, natural waters and some food samples.     

Study on solid phase extraction and graphite furnace atomic absorption spectrometry for the determination of nickel, silver, cobalt, copper, cadmium and lead with MCI GEL CHP 20Y as sorbent

A solid phase extraction and graphite furnace atomic absorption spectrometry (GFAAS) for the determination of nickel, silver, cobalt, copper, cadmium and lead with MCI GEL CHP 20Y as sorbent was studied. Trace amounts of chromium, nickel, silver, cobalt, copper, cadmium and lead were reacted with 2-(2-quinolinil-azo)-4-methyl-1,3-dihydroxidobenzene (QAMDHB) followed by adsorption onto MCI GEL CHP 20Y solid phase extraction column, and 1.0molL(-1) HNO(3) was used as eluent. The metal ions in 300mL solution can be concentrated to 1.0mL, representing an enrichment factor of 300 was achieved. The recoveries of analytes at pH 8.0 with 1.0g of resin were greater than 95% without interference from alkaline, earth alkaline and some metal ions. When detected with graphite furnace atomic absorption spectrometry, the detection limits in the original samples were 1.4ngL(-1) for Cr(III), 1.0ngL(-1) for Ni(II), 0.85ngL(-1) for Ag(I), 1.2ngL(-1) for Co(II), 1.0ngL(-1) for Cu(II), 1.2ngL(-1) for Cd(II) and 1.3ngL(-1) for Pb(II). The validation of the procedure was performed by the analysis of the certified standard reference materials, and the presented procedure was applied to the determination of analytes in biological, water and soil samples with good results (recoveries range from 89 to 104%, and R.S.D.% lower than 3.2%. The results agreed with the standard value or reference method).     

Coprecipitation of gold(III), palladium(II) and lead(II) for their flame atomic absorption spectrometric determinations

An enrichment-separation procedure based on the coprecipitation of gold(III), palladium(II) and lead(II) ions with nickel(II)-5-methyl-4-(2-thiazolylazo) resorcinol complex has been developed. The analytical parameters including pH, amounts of 5-methyl-4-(2-thiazolylazo) resorcinol, sample volume, etc. was investigated for quantitative recoveries of Au(III), Pd(II) and Pb(II). Interference due to various cations and anions has also been investigated. The detection limits for analyte ions by 3sigma were 2.6 microg L(-1) for lead, 1.5 microg L(-1) for gold, 2.1 microg L(-1) for palladium. The accuracy of the method was evaluated by the analysis of certified reference materials (NIST SRM 2711 Montana soil, GBW 07309 Stream sediment). The proposed procedure was successfully applied to environmental samples for the determinations of analytes.     

Solid-phase extraction of Fe(III), Pb(II) and Cr(III) in environmental samples on amberlite XAD-7 and their determinations by flame atomic absorption spectrometry

This paper describes a simple and accurate procedure for preconcentration of trace amounts of Fe(III), Pb(II) and Cr(III) ions. The preconcentration procedure is based on retention of p-xylenol blue chelates on Amberlite XAD-7. The analytes retained were eluted from Amberlite XAD-7 by using 1 mol L(-1) HCl. The influences of the analytical parameters including amounts of reagents, pH and type of eluent were also investigated. The detection limits of Fe, Pb and Cr were found to be 3.07, 18.6 and 3.27 microg L(-1), respectively. The accuracy of the procedure was checked by the analysis of an electrolytic copper wire sample. The relative error was less than 5%. The presented method was applied to the determination of Fe(III), Pb(II) and Cr(III) in water samples from Denizli, Turkey with good results such as recoveries more than 95%, relative standard deviations below 10%.     

Determination of trace metals by atomic absorption spectrometry after coprecipitation with europium hydroxide

A procedure for the determination of trace amounts of chromium(III), iron(III), lead(II) and manganese(II) is described, that combines atomic absorption spectrometry-europium hydroxide coprecipitation. The influences of analytical parameters including amount of europium(III), amount of ammonia, sample volume, etc. were investigated on the recoveries of analyte ions. The effects of concomitant ions were also examined. The recoveries of the analyte ions were in the range of 95-104%. The detection limits (3 s) were in the range of 1.7-17.1 microg/L. The validation of the presented coprecipitation procedure was performed by the analysis of Bovine Liver 1577-b and BCR-144R Sewage Sludge (domestic origin) standard reference materials. The method was applied to the determination of analytes in real samples including natural waters and some food, soil and fertilizer samples, etc. and good results were obtained (relative standard deviations < 10%, recoveries > 95%).     

Solid phase extraction of heavy metal ions in environmental samples on multiwalled carbon nanotubes

Multiwalled carbon nanotubes (MWNTs) were used as solid phase extractor for Cu(II), Cd(II), Pb(II), Zn(II), Ni(II) and Co(II) ions as ammonium pyrrolidine dithiocarbamate (APDC) chelates, in the present study. The influences of the experimental parameters including pH of the solutions, amounts of MWNTs, amounts of APDC, eluent type and volume, sample volume etc. on the quantitative recoveries of analyte ions were investigated. The effects of matrix ions of natural waters and some transition metals on the recoveries of the analyte ions were also examined in the model solutions. Tests of addition/recovery for analyte ions in real samples were performed with satisfactorily results. The detection limits (3s) for the analyte ions were in the range of 0.30-0.60 microg l(-1). The concentrations of analytes in standard reference materials (NIST RM 8418 Wheat gluten, LGC 6010 Hard drinking water and NIST SRM 1515 Apple leaves) pretreated by the presented method were measured with FAAS and the analytical values were well agreed with the certified values and the reference values without the interference of major components. The presented method has been applied to the determination of analytes in food and environmental samples with satisfactory results.     

On-line solid phase selective separation and preconcentration of Cd(II) by solid-phase extraction using carbon active modified with methyl thymol blue

An on-line flow system was used to develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium. The method is based on adsorption of cadmium ions onto the activated carbon modified with methyl thymol blue. Then the adsorbed ions were washed using 0.5M HNO(3) and the eluent was used to determine the Cd(II) ions using flame atomic absorption spectrometry. The results obtained show that the modified activated carbon has the greatest adsorption capacity of 80 microg of Cd(II) per 1.0 g of the solid phase. The optimal pH value for the quantitative preconcentration was 9.0 and full desorption is achieved by using 0.5M HNO(3) solution. It is established that the solid phase can be used repeatedly without a considerable adsorption capacity loss. The detection limit was less than 1 ngmL(-1) Cd(II), with an enrichment factor of 1000. The calibration graph was linear in the range of 1-2000 ngmL(-1) Cd(II). The developed method has been applied to the determination of trace cadmium (II) in water samples and in the following reference materials: sewage sludge (CRM144R), and sea water (CASS.4) with satisfactory results. The accuracy was assessed through recovery experiments.     

A solid phase extraction procedure for Fe3+, Cu2+ and Zn2+ ions on 2-phenyl-1H-benzo[d] imidazole loaded on Triton X-100-coated polyvinyl chloride

A new and efficient solid phase extraction method is described for the preconcentration of trace heavy metal ions. The method is based on the adsorption of Fe(3+), Cu(2+) and Zn(2+) on 2-phenyl-1H-benzo[d] imidazole (PHBI) loaded on Triton X-100-coated polyvinyl chloride (PVC). The influences of the analytical parameters including pH and sample volume were investigated. Common coexisting ions did not interfere on the separation and determination of analytes under study. The adsorbed analytes were desorbed by using 5 mL of 4 mol L(-1) nitric acid. The preconcentration factor is 90. The detection limits (3 sigma) were in the range of 0.95-1 microg L(-1). The sorbent exhibited excellent stability and its sorption capacity under optimum conditions has been found to be more than 2.7 mg of ions per gram of sorbent. The recoveries of analytes were generally higher than 95%. The relative standard deviations (R.S.D.s) were generally lower than 4%. The method has been successfully applied to some real samples.     

A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.     

Preconcentration and separation of trace amount of heavy metal ions on bis(2-hydroxy acetophenone)ethylendiimine loaded on activated carbon

A sensitive and simple method for simultaneous preconcentration of trace heavy metal ions in some food samples has been reported. The method is based on the adsorption of Cr(3+), Fe(3+), Cu(2+), Ni(2+), Co(2+) and Zn(2+) on bis(2-hydroxy acetophenone)ethylendiimine (BHAPED) loaded on activated carbon (AC). The adsorbed metals on activated carbon were eluted using 2 mol L(-1) nitric acid in acetone. The influences of the analytical parameters including pH and sample volume were investigated. The effects of matrix ions on the recoveries of analyte ions were also investigated. The recoveries of analytes were generally higher than 94%. The method has been successfully applied for analysis of the metal contents in real samples including natural water samples.     

A multi-element solid-phase extraction method for trace metals determination in environmental samples on Amberlite XAD-2000

A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L(-1) nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N=20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 microg L(-1), respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala).     

Penicillium digitatum immobilized on pumice stone as a new solid phase extractor for preconcentration and/or separation of trace metals in environmental samples

This study presents a column solid phase extraction procedure based on column biosorption of Cu(II), Zn(II) and Pb(II) ions on Penicillium digitatum immobilized on pumice stone. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions such as: pH values, amount of solid phase, elution solution and flow rate of sample solution were evaluated for the quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes has also been investigated. The recoveries of copper, zinc and lead under the optimum conditions were found to be 97+/-2, 98+/-2 and 98+/-2%, respectively, at 95% confidence level. For the analytes, 50-fold preconcentration was obtained. The analytical detection limits for Cu(II), Zn(II) and Pb(II) were 1.8, 1.3 and 5.8 ng mL(-1), respectively. The proposed procedure was applied for the determination of copper, zinc and lead in dam water, waste water, spring water, parsley and carrot. The accuracy of the procedure was checked by determining copper, zinc and lead in standard reference tea samples (GBW-07605).