Umit Divrikli

Coprecipitation of heavy metals with erbium hydroxide for their flame atomic absorption spectrometric determinations in environmental samples.

Trace amounts of copper, manganese, cobalt, chromium, iron and lead were quantitatively coprecipitated with erbium hydroxide on 0.05M NaOH medium. The coprecipitant could be easily dissolved with 1M nitric acid. The presence of up to 15g/l of erbium ions did not interfere with the atomic absorption spectrometric determination of analyte ions. The recovery values for analyte ions were higher than 95%. The concentration factor was 25-fold. Coprecipitation parameters including reagent amounts and matrix effects are discussed. The relative standard deviations of the determinations were below 9%. The time required for the coprecipitation was about 30min. The proposed method was successfully applied for the determination of trace amounts of analyte ions in urine, soil and sediment, natural water samples.

Determination of some trace metals in water and sediment samples by flame atomic absorption spectrometry after coprecipitation with cerium (IV) hydroxide

A cerium(IV) hydroxide coprecipitation method was developed for the determination of some trace elements (Cu, Co, Pb, Cd, Ni) in aqueous solutions, water and sediment samples by flame atomic absorption spectrometry (AAS). Several parameters governing the efficiency of the coprecipitation method were evaluated including pH of sample solution, amount of carrier element, volume of sample solution and the effect of possible matrix ions The procedure was validated by the analysis of GBW 07309 standard reference material sediment and by use of a method based on a solid phase extraction.

Preconcentration of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) as calmagite chelates on cellulose nitrate membrane filter prior to their flame atomic absorption spectrometric determinations.

A method for the preconcentration and determination of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) ions by atomic absorption spectrometry has been described. The method was based the collection of metal-calmagite complexes on a soluble cellulose nitrate membrane filter. The detection of the solution was obtained by flame atomic absorption spectrometry (FAAS) after completely dissolving the membrane with 0.5 ml of nitric acid at 80 degrees C. The metal ions were recovered quantitatively at pH 8. Various factors which affect the collection and determination of metal ions such as, type and size of the membrane filter, solvent for dissolution of the species retained on the filter were investigated. The detection limits were varying 0.06 mug l(-1) for Cu to 2.5 mug l(-1) for Cr. An application of the proposed method for analyte ions in mineral and tap water samples was also described with satisfactory results (recoveries >95%, relative standard deviations <10%).

Inorganic arsenic speciation in various water samples with GFAAS using coprecipitation

A simple, economic and sensitive method for selective determination of As(III) and As(V) in water samples is described. The method is based on selective coprecipitation of As(III) with Ce(IV) hydroxide in presence of an ammonia/ammonium buffer at pH 9. The coprecipitant was collected on a 0.45 µm membrane filter, dissolved with 0.5 mL of conc. nitric acid and the solution was completed to 2 or 5 mL with distilled water. As(III) in the final solutions was determined by graphite furnace atomic absorption spectrometry (GFAAS). Under the working condition, As(V) was not coprecipitated. Total inorganic arsenic was determined after the reduction of As(V) to As(III) with NaI. The concentration of As(V) was calculated by the difference of the concentrations obtained by the above determinations. Both the determination of arsenic with GF-AAS in presence of cerium and the coprecipitation of arsenic with Ce(IV) hydroxide were optimised. The suitability of the method for determining inorganic arsenic species was checked by analysis of water samples spiked with 4–20 µg L−1 each of As(III) and As(V). The preconcentration factor was found to be 75 with quantitative recovery (≥95%). The accuracy of the present method was controlled with a reference method based on TXRF. The relative error was under 5%. The relative standard deviations for the replicate analysis ( n = 5) ranged from 4.3 to 8.0% for both As(III) and As(V) in the water samples. The limit of detection (3σ) for both As (III) and As(V) were 0.05 µg L−1. The proposed method produced satisfactory results for the analysis of inorganic arsenic species in drinking water, wastewater and hot spring water samples.

Trace Heavy Metal Levels in Street Dust Samples from Yozgat City Center, Turkey

Abstract The copper, cadmium, chromium, nickel, lead, manganese and cobalt contents of dust samples taken from Yozgat city center, Turkey were determined by flame atomic absorption spectrometry after digestion with aqua regia. The highest levels of the trace metal ions in the streets with heavy traffic were noted. The lowest levels of the metal concentrations were found in the samples from hospital and health centers. The results found in the present study were compared with some cities around the world. The levels of the metal ions found were generally below the mean world-wide contents of the street dust samples. Correlations between heavy trace metal levels of the dust samples were also evaluated.

Selective extraction of chromium(VI) using a leaching procedure with sodium carbonate from some plant leaves, soil and sediment samples

Speciation of chromium in some plant leaves, soil and sediment samples was carried out by selective leaching of Cr(VI) using a sodium carbonate leaching procedure. Total chromium from the samples was extracted using aqua regia and oxidative acid digestion, respectively. The concentrations of chromium species in the extracts were determined using by graphite furnace atomic absorption spectrometry (GFAAS). Uncoated graphite furnace tubes were used as an atomizer. Due to the presence of relatively high amounts of Na(2)CO(3) in the resulting samples, the possible influences of Na(2)CO(3) on the absorbance signals were checked. There is no interference of Na(2)CO(3) on the chromium absorbance up to 0.1 mol L(-1) Na(2)CO(3). A limit of detection (LOD) for determination of Cr(VI) in 0.1 Na(2)CO(3) solution by GFAAS was found to be 0.93 microg L(-1). The procedure was applied to environmental samples. The relative standard deviation, R.S.D. as precision for 10 replicate measurements of 20 microL(-1) Cr in processed soil sample was 4.2%.

Preconcentration‐Separation of Heavy Metal Ions in Environmental Samples by Membrane Filtration‐Atomic Absorption Spectrometry Combination

Abstract The preconcentration performance characteristics of cellulose nitrate membrane filter were investigated for the atomic absorption spectrometric determinations of traces metal ions in the environmental samples. The method was optimized for several parameters, including buffer pH, matrix, and type of the membrane. The investigated analyte ions were collected on cellulose nitrate membrane filter as their 8‐hydroxyquinoline (8‐HQ) (oxine) complexes. Then membrane filter was dissolved by using small amounts of concentrated nitric acid. The levels of copper, iron, cobalt, and cadmium ions in the final solutions were determined by flame atomic absorption spectrometry (FAAS). The recoveries of analytes were generally in the range of 94–102%. No influences have been observed from the matrix of the natural water samples. The presented procedure was applied for the determinations of analyte ions contents of natural waters, some ammonium salts, and microwave digested black tea samples with satisfactory results. The relative standard deviations of the determinations were below 9%. The method was verified by the analysis of two reference standard materials (GBW 07309 stream sediment and NRCC‐SLRS‐4 Riverine Water).

On-line preconcentration of copper as its pyrocatechol violet complex on Chromosorb 105 for flame atomic absorption spectrometric determinations

An on-line solid phase extraction method for the preconcentration and determination of Cu(II) by flame atomic absorption spectrometry (FAAS) has been described. It is based on the adsorption of copper(II) ion onto a home made mini column of Chromosorb 105 resin loaded with pyrocatechol violet at the pH range of 5.0-8.0, then eluted with 1 mol L(-1) HNO(3). Several parameters, such as pH of the sample solution, amount of Chromosorb 105 resin, volume of sample and eluent, type of eluent, flow rates of sample and eluent, governing the efficiency and throughput of the method were evaluated. The concentration of the copper ion detected after preconcentration was in agreement with the added amount. At optimized conditions, for 15 min of preconcentration time (30 mL of sample volume), the system achieved a detection limit of 0.02 microg L(-1), with relative standard deviation 1.1% at 0.03 microg mL(-1) copper. The present method was found to be applicable to the preconcentration of Cu(II) in natural water samples.

Separation and Enrichment of Gallium(III) as 4-(2-Thiazolylazo) Resorcinol (TAR) Complex by Solid Phase Extraction on Amberlite XAD-4 Adsorption Resin

Abstract A rapid, sensitive, and facile method for enrichment and separation of trace amounts of gallium was established by using mini column filled Amberlite XAD-4. Gallium(III) as a 4-(2-thiazolylazo) resorcinol (TAR) complex is sorbed on the Amberlite XAD-4 resin and is easily eluted by using 1 M nitric acid in acetone. The determinations of gallium were performed by atomic absorption spectrometry. The influences of the analytical parameters including amounts of reagents, pH of the solutions, and type of eluent were also investigated. The influences of several ions, as interferents, were discussed. The accuracy of the method was demonstrated by recovery on spiked samples. The presented procedure was applied to the determination of gallium in reference standard sediment material (GBW 07309) and water samples with satisfactory results (recovery 95%; relative error 3%; relative standard deviation 10%).

A novel strategy for chromium speciation at ultra-trace level by microsample injection flame atomic absorption spectrophotometry

Simple, robust and novel analytical procedures were developed for the speciation of chromium by carrier element co-precipitation (CECP) and dispersive liquid–liquid microextraction (DLLME) coupled with microsample injection system–flame atomic absorption spectrophotometry (MIS–FAAS). Ammonium pyrrolidine dithiocarbamate (APDC), carbon tetrachloride and ethanol were used as chelating agent, extraction solvent and disperser solvent, respectively for the determination of Cr(VI) by DLLME. For total chromium, Cr(III) was oxidized by Ce(SO4)2 in acidic media (0.07 mol L−1 H2SO4) and the resulting solution was co-precipitated with APDC. The concentration of Cr(III) was estimated by determining the difference between the concentration of total chromium and that of Cr(VI). The maximum recovery of Cr(VI) was obtained with DLLME at optimal conditions of pH 3.0 , 0.25% APDC, 100 μL CCl4, 1.00 mL of CH3CH2OH and 0.01 mg L−1 Cr(VI). Whereas, the optimal conditions for CECP were 40 mL initial volume of water samples, 0.25% APDC, 0.02% Ce(SO4)2 and 0.10 mg L−1 Cr(VI) concentration. The limits of detection and enrichment factor of DLLME and CECP were [0.037 and 2.13] and [400 and 100] μg L−1, respectively with 40 mL initial volumes. The relative standard deviations (RSD, n = 6) were <4%. The proposed method was successfully applied to the chromium speciation at ultra-trace levels in natural drinking water, industrial effluents waste water and an exchangeable fraction of garden soil from Denizli. Moreover, the proposed methods compared well with the literature reported method.