Solid Sampling Atomic Absorption Spectrometry Research Articles

Determination of the total mercury in contaminated soils by direct solid sampling atomic absorption spectrometry using an AMA-254 device and radiochemical neutron activation analysis

High total mercury (T-Hg) contents in soils, up to 25mgkg−1, were determined by two independent methods: a one-purpose atomic absorption spectrometer AMA-254 (Advanced Mercury Analyser) with direct solid sampling and radiochemical neutron activation analysis (RNAA), using sample masses of 10mg to 25mg and about 150mg, respectively. An excellent agreement between results of both methods was obtained. For quality control (QC) purposes, NIST SRM 2711 Montana Soil and NIST SRM 2711a were analyzed by both methods using the above sample masses. The results obtained compared with the NIST certified values within the uncertainty margins, thus proving the accuracy of the procedures employed. A new mercury value of 1.42mgkg−1±0.12mgkg−1 was determined in NIST SRM 1648a Urban Particulate Matter by RNAA. For achieving accurate results by the AMA-254 spectrometer, optimizing of the analytical procedure was necessary, consisting of analyzing small (10mg to 25mg) sample masses. It has been found that the cryogenic grinding used provided sufficiently representative and homogeneous samples. In view of the decomposition procedures employed in AMA-254 and RNAA procedures, it can be inferred that the mercury contained in QC samples was presumably bound in an organic fraction. A test in which HgS was analyzed by RNAA showed that even mercury present in sulfide form would be fully recovered using the procedures employed.

A rapid solid sampling method for determination of nickel and copper along human hair by ETAAS

A procedure for copper and nickel determination in scalp hair by solid sampling electrothermal atomic absorption spectrometric method was described. The hair samples (0.02 to 0.4 mg) were inserted directly on the platforms of solid sampling autosampler. The effects of pyrolysis temperature, atomization temperature, the amount of sample as well as addition of a modifier (Pd/Mg) and/or auxiliary digesting agents (hydrogen peroxide and nitric acid) and/or a surfactant (Triton X-100) on the determination of copper and nickel by solid sampling atomic absorption spectrometry were investigated. After optimization of parameters, the average recoveries of copper in two different certified reference hair samples were 105.7 and 97.6%. The recoveries of nickel in the both certified reference hair samples were in 95.2 and 96.4%. The limits of detection (3σ, N = 10) for copper and nickel were 22 ng/g and 35 ng/g, respectively. Heterogenous distribution of analyte in microscale for segmental analysis could be determined which is important to know that analyte quantity and time of poisoning of a person was exposed. For this purpose, 0.5 cm of pieces were cut along one or a few close strands and analyzed by solid sampling. This process could not be performed by wet-digestion method because 50 mg of sample is needed each time. Finally, the method was applied for the determination of copper and nickel concentrations in the hairs of different persons.

Differential determination of trace amounts of arsenic(III) and arsenic(V) in seawater by solid sampling atomic absorption spectrometry after preconcentration by coprecipitation with a nickel–pyrrolidine dithiocarbamate complex

A sensitive and accurate method for the differential determination of trace amounts of arsenic(III) and arsenic(V) in water samples was described. It was found that arsenic(III) was coprecipitated quantitatively with a Ni–ammonium pyrrolidine dithiocarbamate (APDC) complex at the pH range of 2–3, but arsenic(V) was hardly coprecipitated with the Ni–PDC complex in the same pH condition. The coprecipitates obtained were directly measured by electrothermal atomic absorption spectrometry (ETAAS) using the solid sampling technique. In order to determine trace amounts of total arsenic, sodium thiosulfate and potassium iodide were used to reduce arsenic(V) to the trivalent state in the sample solution before coprecipitation. The concentration of arsenic(V) in the sample solution could be calculated by the difference in concentration between arsenic(III) and total arsenic in the sample solution. The coprecipitation conditions for trace amounts of arsenic(III) and arsenic(V) in water samples by the Ni–PDC complex were investigated in detail. The concentration factor by coprecipitation was reached at about 40 000 when 2 mg of nickel as a carrier element was added to 500 ml of the water sample. The proposed method was successfully applied to the determination of trace amounts of arsenic(III) and arsenic(V) in seawater, and the detection limit for arsenic, which was defined as the concentration calculated from three times of the standard deviation of the procedural blanks, was 0.02 ng/ml for 500 ml portions of water sample in the proposed method.

Investigation of air pollution in Chile using biomonitors

A project has been undertaken to carry out a long term study on atmospheric air pollution in Chile using biomonitors. Samples of different species of lichens were collected in clean areas (native forest), analyzed and transplanted to the Santiago Metropolitan Area. In addition, samples of Tillandsia recurvata were collected in the Metropolitan Area for comparison purposes. The preparation of the samples was done under controlled, cryogenic conditions and analyzed by neutron activation analysis and solid sampling atomic absorption spectrometry. As part of the routine QA/QC procedures, the analytical laboratories, have participated in intercomparison runs organized by the IAEA for the determination of trace and minor elements in two lichens samples. The present paper describes the activities carried out within the framework of this project.

Preconcentration by coprecipitation of arsenic and tin in natural waters with a Ni-pyrrolidine dithiocarbamate complex and their direct determination by solid-sampling atomic-absorption spectrometry.

A method for the determination of trace amounts of arsenic and tin in natural waters is described. Trace amounts of arsenic and tin were preconcentrated by coprecipitation with a Ni-ammonium pyrrolidine dithiocarbamate (APDC) complex. The coprecipitates obtained were directly analyzed by graphite-furnace atomic-absorption spectrometry (GFAAS) using the Ni-APDC complex solid-sampling technique. The coprecipitation conditions used for the trace amounts of arsenic and tin in natural water were investigated in detail. It was found that arsenic and tin at sub-ng mL(-1) levels were both coprecipitated quantitatively by Ni(PDC)2 in the pH range 2-3. The concentration factors by coprecipitation reached approximately 40,000 when 2 mg nickel was added as a carrier element to 500 mL of the water sample. The proposed method has been applied to the determination of trace amounts of arsenic and tin in river water and seawater reference materials, and the detection limits for arsenic and tin, which were calculated from three times of the standard deviation of the procedural blanks, are 0.02 ng mL(-1) and 0.04 ng mL(-1), respectively, for 500-mL volumes of water sample.

Analyte transport efficiencies in electrothermal vaporization for inductively coupled plasma mass spectrometry.

A modified graphite furnace for solid-sampling atomic absorption spectrometry as an electrothermal vaporizer (ETV) was coupled to a Perkin-Elmer/Sciex ELAN 6000 ICP mass spectrometer. The integrals obtained from electrothermal vaporization of aliquots containing As, Cd, Cu, Co, Fe, Mn, Pb, Se, and Zn were compared with those obtained from pneumatic nebulization of the same aqueous standard solution. The pneumatic nebulizer was calibrated by weighing the mass of aqueous aerosol trapped on a filter. With "wet plasma" conditions maintained also for measurements with the ETV and reference signals for analyte signals obtained with the calibrated pneumatic nebulization, the transport efficiency of the ETV system, e.g. the ratio of the analyte amount introduced into the plasma to that amount dosed into the vaporizer, was determined. The transport efficiency of two different tube and interface designs has been evaluated. Investigations with and without the use of trifluoromethane as reactive gas, with different furnace heating rates, and with varying gas flows were performed. In general, the tube equipped with a nozzle led to generally higher transport efficiency than the standard tube. Without trifluoromethane transport efficiencies ranged from 10% to 35% with the standard tube and from 15% to 50% with the nozzle-type tube. With addition of 2 mL min(-1) trifluoromethane to the argon flow of 400 mL min(-1) through the tube, transport efficiencies from 20% to 70% and from 70% to 100% were achieved with the standard and nozzle-type tubes, respectively.

Electrothermal atomic absorption spectrometry using an improved solid sampling system for the analysis of high purity tantalum powders

A solid sampling atomic absorption method for the determination of Cu, Fe, Mn, Na and Zn in high-purity tantalum powders has been developed. It is based on a direct automatic introduction of the sample into the graphite tube using the platform technique. Standard hollow-cathode lamps in combination with deuterium background correction are used as radiation sources. This and some additional modifications of the Grün spectrometer hard- and software lead to a significant improvement of its performance. With the maximum applicable sample mass of 40 mg limits of detection of 1 ng g −1, 27 ng g −1, 1.5 ng g −1, 0.7 ng g −1 and 0.1 ng g −1, respectively, are achieved for Cu, Fe, Mn, Na and Zn. Aqueous standard solutions are used for calibration. Comparison of the results obtained by solid sampling atomic absorption spectrometry with those of the liquid sampling technique show satisfactory agreement.

Sources of error in direct solid sampling Zeeman atomic absorption spectrometry analyses of biological samples with high water content

Analytical errors were quantified in the direct analyses of trace elements in samples with high water content by means of solid sampling atomic absorption spectrometry with Zeeman effect background correction (direct SS-ZAAS). Time versus mass curves for HNO 3 (0.1 mol 1 −1), blood, kidney and liver at different temperatures (+20, +4, −20°C) and mass input (0.07 to 42 mg) were observed. Following a stabilization period, mass losses appeared to be nearly linear and independent of input mass. By means of a function using observed stabilization time and mass losses a 10% increase in analyte content was calculated as occurring at and below 0.06 mg. Experimentally, 10% increases were found to occur within a range 0–0.07 mg for weighed Cd solutions (0.1 and 0.2 ng mg −1 in 0.1 mol 1 −1 HNO 3 at 5°C). An automated solid sampling system consisting of microbalance, dispenser, transport system and electronics was integrated in the experiments. Manual working time and the necessity of operator presence were reduced by at least 80%. Performance and capacity compared well to the manual SS-ZAAS mode. Automated SS-ZAAS analysis in fresh animal tissues is proposed for use as a screening and reference method in official residue control.

Packed glassy carbon tube atomizer for direct determinations by atomic absorption spectrometry, free from background absorption

An electrothermal atomizer consisting of a long glassy carbon tube packed with activated charcoal was evaluated for the direct determination of trace elements in biological materials by atomic absorption spectrometry, in the absence of any background absorption. The maximum temperature of the atomizer of 2280 °C was maintained continuously by an electric power supply of about 7 kW. Under such isothermal conditions, few chemical interferences and high accuracy (relative error <8%) and precision (RSO <3.5%) were obtained in the direct determination of trace elements (Cu, Mg and Mn) in National Institute of Standards and Technology biological Standard Reference Materials by solid sampling atomic absorption spectrometry.

A new preparation method of calibration graphs for direct analysis of powdered biological samples by solid sampling atomic absorption spectrometry. Standard addition method for solid sampling technique.

A new preparation method of calibration graphs for direct analysis of powdered biological samples by solid sampling atomic absorption spectrometry. Standard addition method for solid sampling technique.

Solid sampling atomic absorption spectrometry and matrix composition of organic reference materials

Abstract

Cadmium and zinc concentrations in fetal and maternal rat tissue after parenteral administration of cadmium during pregnancy.

Cadmium (Cd) and zinc (Zn) concentrations were determined by solid sampling atomic absorption spectrometry (AAS) in rat maternal and fetal tissues after exposure to cadmium. Cadmium was administered subcutaneously as CdCl2 in saline daily during pregnancy. Two experiments were performed. In expt. I we investigated the tissue concentration at day 19 (gestational age) after administration of several doses: 0, 1.1, 2.2, 4.4, and 8.8 mumol Cd/kg/day. In expt. II the course of the Cd and Zn concentrations during pregnancy was investigated by collecting samples at days 14, 16, 18 and 20, after daily injections of 4.4 mumol Cd/kg. Cadmium concentrations in blood, maternal liver, placenta and fetal liver increased with dose and duration of exposure. Cadmium was heavily accumulated in the liver and transferred to the fetus only in small amounts. The zinc concentration in the maternal liver was positively correlated with the cadmium concentration. In the placenta the zinc concentration was not affected. Zinc in fetal liver was decreased from day 18 onward. Despite relatively high cadmium levels and decreased zinc levels in the fetus, we observed no adverse effects on various reproduction parameters, such as birth weights and obvious malformations.

Direct atomic absorption spectrometric determination of chromium, cobalt and nickel in fish protein concentrate and dried fish solubles

Solid-sampling atomic absorption spectrometry was used for the determination of chromium, cobalt and nickel in four types of fish protein concentrate and a sample of dried fish solubles. The samples (0.3–10 mg) were introduced through the injection port of the graphite furnace by means of a special injector. The metals in the fish protein concentrate were determined from peak height measurements, by comparison with the International Atomic Energy Agency reference standard Dried Fish Solubles as the solid standard. The contents (in ppm) of chromium, cobalt and nickel were found to lie in the ranges 0.2–1.8, 0.07–0.3, and 0.7–2.8, respectively; the relative standard deviations were 5–16%.