Sonja Arpadjan

Sorption of Arsenic, Bismuth, Mercury, Antimony, Selenium and Tin on Dithiocarbamate Loaded Polyurethane Foam as a Preconcentration Method for Their Determination in Water Samples by Simultaneous Inductively Coupled Plasma Atomic Emission Spectrometry and Electrothermal Atomic Absorption Spectrometry

Column solid-phase extraction using dithiocarbamate loaded polyurethane foam was applied to the preconcentration of trace amounts of As, Bi, Hg, Sb, Se and Sn from water samples prior to their measurement by simultaneous ICP-AES and ETAAS. The sorption recoveries of all the analytes were higher than 97% for 150 ml water sample solutions passed through the column with pH ≈ 4.5 and sodium chloride concentration up to 3%. For As, Bi, Hg, Sb and Se, quantitative solid-phase extraction can be achieved over a wide pH range, from 0.5 to pH 5. The combination of the proposed preconcentration method with subsequent simultaneous analyte determination in the methanol eluates by ICP-AES permits the detection of 3 µg l - 1 As and Se, 8 µg l - 1 Bi, 0.12 µg l - 1 Hg, 2 µg l - 1 Sb and 6 µg l - 1 Sn in water samples. ETAAS measurement after dissolution of the sorbed analytes in isobutyl methyl ketone allows the detection of 0.06 µg l - 1 As and Sb, 0.1 µg l - 1 Bi and Sn, 0.08 µg l - 1 Se and 0.3 µg l - 1 Hg.

Determination of trace elements in analytical-reagent grade sodium salts by atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry after preconcentration by column solid phase extraction

Column solid phase extraction using solid ammonium hexahydroazepine-1-dithiocarboxylate (ammonium hexamethylenedithiocarbamate)(HMDC) mixed with polyurethane foam was applied to the preconcentration of trace amounts, of Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni and Pb from analytical-reagent grade sodium salts prior to their measurements by atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES). A 2 ml disposable syringe served as a preconcentration column. Except for Cr, recoveries of sorption of the elements tested were higher than 98% with absolute blanks ranging between 5 ng (Co) and 50 ng (Cu). For AAS determination of the preconcentrated analytes, the solid chelate forming sorbent (HMDC) was completely dissolved in isobutyl methyl ketone (IBMK). Electrothermal AAS allows the determination of 1 × 10–7% Cd, 3 × 10–7% Mn, 5 × 10–7% Pb, 1 × 10–6% Co, 2 × 10–6% Ni, 4 × 10–6% Fe and 1 × 10–5% Cu. For ICP-AES measurements a quantitative elution was obtained with 4 mol l–1 HNO3 permitting the determination of 5 × 10–6% Cd and Mn, 1 × 10–5% Cu and Fe, 2 × 10–5% Ni and 1 × 10–4% Pb. The elution of Co and Hg from the sorbent with 4 mol l–1 HNO3 was incomplete.

Column solid phase extraction as preconcentration method for trace element determination in oxalic acid by atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry

Abstract Column solid phase extraction using solid sorbent [Foam-Pap - hexamethyleneammonium hexamethylenedithiocarbamate (HMDC) immobilized on polyurethane (PU) foam mixed with methyltrioctylammonium chloride (MTOAC) immobilized on filter paper as well as the solid sorbent PU-HMDC-MTOAC mixture of the above ligands immobilized on polyurethane foam only] was applied to the preconcentration of traces of Cd, Co, Cu, Hg, Ni and Pb in analytical-reagent grade oxalic acid prior to their measurements by atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES). A disposable syringe served as a preconcentration column. Recoveries of sorption of the analytes were higher than 97%. For AAS determinations the solid chelate forming sorbents (HMDC and MTOAC) were completely dissolved in isobutyl methyl ketone (IBMK). The sorption on Foam-Pap sorbent combined with electrothermal AAS (ETAAS) allows the determination of 0.1 ng g −1 Cd, 0.3 ng g −1 Pb, 1 ng g −1 Ni, 2 ng g −1 Co and Cu, and 0.1 μg g −1 Hg. For ICP-AES measurements a quantitative elution was obtained with 4 mol 1 −1 HNO 3 for Cd, Cu, Ni and Pb, permitting the determination of 0.05 μg g −1 Cd, 0.1 μg g −1 Cu, 0.2 μg g −1 Ni and 1.0 μg g −1 Pb. The PU-HMDC-MTOAC sorbent permits the quantitative preconcentration of Cd, Cu, Fe, Hg and Pb. The combination of sorption on PU-HMDC-MTOAC sorbent with subsequent ETAAS determination allows the determination of 0.3 ng g −1 Pb, 0.4 ng g −1 Cd, 2 ng g −1 Cu and Fe, and 0.1 μg g −1 Hg.

Determination of thallium in wine by electrothermal atomic absorption spectrometry after extraction preconcentration

Abstract A simple method for extraction electrothermal atomic absorption spectroscopy (ETAAS) determination of Tl in wine is described. The wine sample is decomposed with a mixture of nitric acid and hydrogen peroxide and both thallium species Tl(I) and Tl(III) are extracted from 0.5 mol l−1 KI solution into iso-butyl methyl ketone (IBMK). Optimal parameters for ETAAS measurement of the iodide complexes extracted were defined for two different instruments: Perkin Elmer Zeeman 3030 (HGA 600) and Varian SpectrAA-880 (GTA-100). Modifiers of tartaric acid, Pd [ammoniumtetrachloropaladate (II)] or Ag (silver nitrate) were investigated for thermal stabilization of such extremely volatile species as iodide complexes of Tl. The analytical procedure developed permits 50-fold preconcentration and determination of 0.05 μg l−1 Tl in wine. The relative standard deviation ranges from 6 to 12% for the concentration range 0.2–1 μg l−1 Tl in wine.

Direct analysis of natural waters for arsenic species by hydride generation atomic absorption spectrometry

Selective reaction media were applied to generate hydrides of total arsenic, As(III), As(V), dimethylarsonic acid (DMA) and monomethylarsonic acid (MMA) from natural waters acidified with HCl (0.1 mol/L HCl in the sample) using reduction with 0.6% NaBH4 in a continuous flow hydride generation system: 1. 1.0 mol/L HCl in the acid channel, water samples pretreated with KI: determination of As(III) + As(V) + MMA 2. 6.0 mol/L CH3COOH in the acid channel: determination of As(III) + DMA 3. 6.0 mol/L CH3COOH in the acid channel, water samples pretreated with KI: determination of As(III) + As(V) + DMA 4. 1.0 M tartaric acid in the acid channel, water samples pretreated with KI: determination of total arsenic As(III) + As(V) + DMA + MMA With the selected medium reactions (1–4) the same response can be obtained for all arsenic species. Calibration with arsenic(III) standard solutions was applicable to the four reactions for arsenic speciation in mineral water, underground water and sea water.

INAA and flame AAS of various vegetable reference materials

SummaryINAA and flame AAS have been used for the analysis of a large number of vegetable reference materials. Out of all determined elements (28 by INAA and 11 by AAS) nine are common for both methods (Ca, Cd, Co, Cu, Fe, Mg, Mn, Na, Zn) and for these the possibilities of the two methods have been compared.

Behaviour of various organic solvents and analytes in electrothermal atomic absorption spectrometry

Factors affecting the determination of trace metal impurities in organic solvents using electrothermal atomic absorption spectrometry have been studied. The behaviour of Cd, Co, Cu, Fe, Ni and Pb in various organic solvents (isobutyl methyl ketone, butyl acetate, toluene and xylene) was investigated. The influence of the nature of the solvent, complexing agent, atomizer type, chemical form and amount of chemical modifier used was evaluated. Optimum conditions with respect to the analyte, solvent and atomizer were established. A comparison of the sensitivities using organic and aqueous solutions is presented.

Chemical modification of volatile elements in organic solvents and extracts by dithiocarbamate and complexes of noble metals in electrothermal atomic absorption spectroscopy

Abstract The behaviour of As, Bi, Cd, Pb, Se, Sb, Sn and Te as dithiocarbamate complexes in isobutyl methyl ketone (IBMK) was investigated using electrothermal atomic absorption spectrometry. Without chemical modification a pyrolysis temperature of 700°C can be used for Bi, 550°C for Cd, 800°C for Pb and 1100°C for Sb. Higher pyrolysis temperatures can be used for As, Se, Sn and Te by utilizing palladium or platinum as ion associate complexes soluble in IBMK. The influence of the furnace tube treatment and of the concentration of Pd or Pt on the pyrolysis and the atomization of the studied dithiocarbamate complexes is discussed.

Reductive coprecipitation and extraction as separation methods for the determination of gold in copper concentrates by AAS and ICP-AES

SummarySimple methods for the determination of gold in copper concentrates are presented. Two separation procedures for gold are proposed. The first preconcentration procedure is based on the reductive coprecipitation of Au using part of the matrix copper as collector. The second implies selective quantitative extraction of Au using the extraction system 0.2 mol/l HCl/IBMK. Flame AAS or ICP-AES are used as instrumental methods and permit the determination of 0.1–50 μg/g gold with a relative standard deviation of 3–12%.

Neutron activation and atomic absorption analysis of Ulva Lactuca and Gracilaria Verrucosa from Thermaikos Gulf, Greece

NAA and AAS have been applied to determine the content of As, Br, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mn, Na, Ni, Pb, Sb, Sc, Sm and Zn in Ulva lactuca and Gracilaria verrucosa from Thermaikos Gulf, Greece. The analytical data has been subjected to cluster and stepwise discriminant analysis. Thus the influence of some industrial sources on the pollution of water in the Gulf is detected and correlation between Zn‐Co‐Cr‐La; Br‐K; Cu‐Ni; Cd‐Sb‐Mn in the investigated algae is established.