Determination of lead in atmospheric particulates by flameless atomic absorption spectrometry with a graphite tube

A procedure for the determination of atmospheric particulate lead by flameless atomic absorption spectrometry is described. Aerosols are collected on 10-cm Whatman 41 filters with high-volume pumps. The lead is removed from a one-eighth sector of the filter by two ultrasonic treatments in 0.1 M nitric acid for 10 and 5 min, respectively. Investigations, including comparison with samples pre-ashed at low temperature, indicated that the lead was completely recovered. Routinely 20-μ1 amounts of the solution are injected into a graphite tube and the % absorption at 283.3 nm is measured. The elements normally encountered in atmospheric aerosols do not interfere. The sensitivity for 24-h samples is 0.01 μg m^?3 of air. Sampling time can be reduced to a few minutes in urban air when a larger segment of the filter is used and a larger volume is injected. The reproducibility of the complete procedure is 3% for a typical lead concentration of 0.35 μg m^?3. The method was applied to short-period variations of the lead concentration in urban air.     

Determination of cadmium in air particulates by flameless atomic absorption spectrometry with a graphite tube

A sensitive and selective determination of cadmium in aerosols by flameless atomic absorption spectrometry is described. By two successive treatments in 0.1 M suprapure nitric acid, the cadmium is removed from the paper filter on which the particulates have been collected. Routinely 10–50 μl of the 100-ml solution are injected into a graphite oven and the % absorption at 228.8 nm is measured. If half a 24-h filter (400 m³ air) is used, the dilution is made to 50 ml and 50 μl is injected, an unusually low concentration of 0.20 ng m^-3 can be determined quantitatively with a relative standard deviation of 10%. The reproducibility of the complete procedure is 4.8%. An interlaboratory comparison indicated that the accuracy is very good. The same solution can also be used for lead determination mostly without any further dilution. As an application, the cadmium concentrations were measured on two different days at 14 stations of the nationwide sampling network, and the influence of nonferrous industries on the cadmium levels is shown.     

Determination of lead in fine particulates by slurry sampling electrothermal atomic absorption spectrometry

A simple method for determining lead in fine particulates (PM2.5) by using electrothermal atomic absorption spectrometry (ETAAS) has been developed. Particulates collected on Nuclepore filter by using a dichotomous sampler were suspended in diluted nitric acid after ultrasonic agitation. The dislodging efficiency is nearly 100% after agitation for 5 min. In order to study the suspension behavior of PM2.5 in solvents, a Brookhaven ZetaPlus Particle Size Analyzer was used to determine the particle size distribution and suspension behavior of air particulates in the solvent. The pre-digestion and modification effect of nitric acid would be discussed. Palladium was added as a chemical modifier and the temperature program of ETAAS was changed in order to improve the recovery. The slurry was introduced directly into a graphite tube for atomization. The metal content in the sample was determined by the standard addition method. In addition, a conventional acid digestion procedure was applied to verify the efficiency of the slurry sampling method. It offers a quick and efficient alternative method for heavy metal characterization in fine particulates.     

Determination of lead in fine particulates by slurry sampling electrothermal atomic absorption spectrometry

A simple method for determining lead in fine particulates (PM_2.5) by using electrothermal atomic absorption spectrometry (ETAAS) has been developed. Particulates collected on Nuclepore filter by using a dichotomous sampler were suspended in diluted nitric acid after ultrasonic agitation. The dislodging efficiency is nearly 100% after agitation for 5 min. In order to study the suspension behavior of PM_2.5 in solvents, a Brookhaven ZetaPlus Particle Size Analyzer was used to determine the particle size distribution and suspension behavior of air particulates in the solvent. The pre-digestion and modification effect of nitric acid would be discussed. Palladium was added as a chemical modifier and the temperature program of ETAAS was changed in order to improve the recovery. The slurry was introduced directly into a graphite tube for atomization. The metal content in the sample was determined by the standard addition method. In addition, a conventional acid digestion procedure was applied to verify the efficiency of the slurry sampling method. It offers a quick and efficient alternative method for heavy metal characterization in fine particulates. Received: 2 August 2000 / Revised: 25 October 2000 / Accepted: 28 October 2000     

Rapid determination of lead in steel by flameless atomic absorption spectrometry

A method for the determination of 1–100 p.p.m. of lead in high- and low-alloy steels by flameless atomic absorption is described. The sample was dissolved in aqua regia. and 2 μl of the diluted solution were pipetted into a Massmann-type furnace. Ashing of the sample at 625°C eliminated influences from hydrochloric acid. Fe, Cr and Ni gave similar negative interferences, which were compensated for by using low-alloy steel with standard additions. An interlaboratory comparison showed that this method gave the same result as extraction with TOPO in MIBK. The procedure could also be applied to commercial instruments. The time for a complete analysis including dissolution was 15 min.     

Determination of sub-nanogram quantities of ruthenium by flameless atomic absorption spectrometry

Flameless atomic absorption spectrometry has been applied to the determination of subnanogram quantities of ruthenium in a variety of matrices encountered in the solidification of nuclear waste. Detection limits ranged to below 10^?10 g, depending on the sample matrix. Most matrix effects could be eliminated by proper selection of atomizer temperature program, allowing the use of a single set of standards in 0.1 N HCl. The one exception was the calcined solid matrix, where a fusion and extraction were used to dissolve the ruthenium and separate it from matrix constituents.     

Determination of manganese in natural waters by flameless atomic absorption spectrometry

Manganese can be rapidly determined in natural waters by direct-injection flameless a.a.s. Interference caused by sea salts in waters of salinity 0–35‰ can be eliminated by charring with ammonium nitrate and with a slow temperature rise. The sensitivity of the determination is depressed by the presence of nitric acid, the depression decreasing with graphite tube age. In saline water matrices, the detection limit is better than 0.002 ng and the sensitivity is better than 0.02 ng for 1% absorbance. Precision is better than 10% for manganese concentrations of 10 μg 1^-1 in sea water.     

Determination of traces of chromium in cocaine and heroin by flameless atomic absorption spectrometry

A method for the determination of total chromium in cocaine and heroin by flameless atomic absorption spectrometry is presented. Cocaine samples were dissolved in 2 ml of HNO(3) 35.0% (v/v) and diluted to 10 ml with ultrapure water; heroin samples were dissolved in ultrapure water, adding 0.4 ml of HNO(3) 35.0% (v/v) to dissolve inert species, and also diluted to 10 ml. Mg(NO(3))(2) and HNO(3), as chemical modifiers, were compared in terms of sensitivity, precision and accuracy, a lower detection limit being obtained for the use of Mg(NO(3))(2), 5.77 mug kg(-1) (7.23 mukg(-1) for HNO(3)). Within-batch precision was found to be 6.19% and 1.48% for drug solution spiked with 0 and 10 mug l(-1) of Cr(3+), respectively, when using Mg(NO(3))(2), and 7.45 and 1.19% for the same respective concentration levels when using HNO(3). Similar results on analytical recovery were obtained for both Mg(NO(3))(2) and HNO(3). Mg(NO(3))(2) was selected as the more adequate of the two chemical modifiers. A study of the introduction of a cooling-down step of 50 degrees C was carried out and compared in terms of sensitivity to the programme without a cooling-down step, but no advantage was observed. Studies on the variation in precision and analytical recovery with the amount of sample, and interferent effects of different species on chromium determination were developed. Finally, chromium concentrations obtained in cocaine samples varied between 0.02 and 0.14 mg kg(-1), the levels in the heroin samples being in the 0.05-0.59 mg kg(-1) range.     

Studies on automated flameless atomic absorption spectrometry

Summary A new device for automated sample injection in flameless AAS with graphite tubes had been investigated. Using solutions of Cd, Pb, Cu, and Ni the attainable precision, the carry-over factor by additional experiments with ⁸⁹Sr, the lifetime of commercially available graphite tubes as well as the influence of some selected matrix types and a pyrolytic coating on the surface of the graphite tubes upon measured values had been studied. The results of these studies together with the hereby resulting advantages of the system and possible future applications are discussed.

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Untersuchungen zur automatisierten flammenlosen Atomabsorptionsspektrometrie

Zusammenfassung Ein neuartiges Gerät zur automatischen Probendosierung bei der flammenlosen AAS mit Graphitrohren wurde untersucht. Mit Lösungen von Cd, Pb, Cu und Ni wurde die erreichbare Reproduzierbarkeit, der Verschleppungsfaktor durch zusätzliche Experimente mit ⁸⁹Sr, die Lebensdauer kommerziell erhältlicher Graphitrohre, der Einfluß einiger ausgewählter Matrices sowie einer pyrolytischen Beschichtung der Oberfläche der Graphitrohre auf die Meßwerte ermittelt. Die Ergebnisse der Studien, die hieraus ersichtlichen Vorteile des Systems sowie zukünftige Einsatzmöglichkeiten werden diskutiert.

Presented at the 6th Annual Symposium on Recent Advances in the Analytical Chemistry of Pollutants, April 21–23, 1976; Vienna, Austria.     

Determination of nanogram quantities of cobalt in complex matrices by flameless atomic absorption spectrometry

The application of flameless atomic absorption spectrometry to determination of a little as 10 pg of Co is described. Cobalt is extracted into ethyl acetate as the pyrrolidinedithiocarbamate complex. This system is effective in removing matrix effects due to high concentrations of various complexing agents, strong oxidants, and reductants that are present in the original samples.     

石墨炉原子吸收光谱法测定茶叶中的铅

采用石墨炉原子吸收光谱法测定茶叶中铅,以NH4H2PO4作为基体改进剂,提高了测定的灰化温度,消除了基体干扰.方法简便,快速,准确度高.通过对标准物质的多次测定,结果均在其保证值范围内,相对标准偏差为2.8%.对样品进行加标回收试验,回收率为96%～105%,方法检出限为0.12μg/L.     

Quantitative measurements of inorganic and organic arsenic by flameless atomic absorption spectrometry

Procedures are described for the determination of arsenicals in water and urine by flameless atomic absorption spectrometry ; these avoid the isolation and transfer of arsine(s) and permit some differentiation between the inorganic and organic (methyl) arsenic content of a sample. Samples of water or urine are heated with hydrochloric acid, and treated with iodide ion. Arsenic species, as the iodides, are extracted into chloroform and then either reextracted into deionized water for measurement of inorganic arsenic, or reextracted into dilute dichromate solution for total arsenic determination; the difference furnishes levels of organic arsenic. Aliquots of the final aqueous extracts are analyzed by graphite-furnace atomic absorption spectrometry, with an arsenic electrodeless discharge lamp. The lower detection limit for water and urine was 10 p.p.b. The recoveries (and Sg values) were: 87.0% (3.0) and 93.0 % (7.9), for inorganic arsenic in water and urine, respectively; 92.3 % (5.3) for mixtures of inorganic and methylated arsenic (total arsenic) in water and urine; and 98.7 % (3.9) and 88.4% (3.6) for dimethylarsenic in water and urine, respectively.     

Determination of lead in biological materials by constant-temperature electrothermal atomic absorption spectrometry

A comparison is made between a platform-equipped Perkin-Elmer HGA-500 and a recently designed two-step constant-temperature graphite furnace with respect to susceptibility to interference effects as well as attainable detection limits. It is shown that larger quantities of biological samples can be used with the constant-temperature furnace without suppressing the analyte signal, resulting in lower detection limits. Materials studied include NBS Olyster Tissue and Bovine Liver, and human lung tissue and human blood.     

Determination of lead in blood by tungsten coil electrothermal atomic absorption spectrometry

A method for the determination of lead in blood using a tungsten coil atomizer is described. A 100 μl volume of the whole blood sample is transferred to a sampler cup containing 100 μl of water plus 300 μl of 0.25% v/v Triton X-100. After lysis of blood cells, 500 μl of 10% w/v trichloroacetic acid is added for protein precipitation and 10 μl of the supernatant solution is automatically delivered into the tungsten coil. The furnace heating program is implemented in 41 s. It is shown by the paired t-test that there is no significant difference at the 5% probability level between results obtained by the proposed method and by using a transversely heated graphite atomizer with a longitudinal Zeeman background correction. Accuracy is also assessed by employing reference materials. The proposed tungsten coil procedure presents a characteristic mass of 15 pg Pb and a detection limit of 1.9 μg Pb dl⁻¹.