Atomic absorption spectrometry, determination Heavy metals

Atomic absorption spectrometry is one of the most widely used techniques for the determination of metals at trace levels in solution. Its popularity as compared with that of flame emission is due to its relative freedom from interferences by inter-element effects and its relative insensitivity to variations in flame temperature. Only for the routine determination of alkali and alkaline earth metals, is flame photometry usually preferred. Over sixty elements can be determined in almost any matrix by atomic absorption. Examples include heavy metals in body fluids, polluted waters, foodstuffs, soft drinks and beer, the analysis of metallurgical and geochemical samples and the determination of many metals in soils, crude oils, petroleum products and plastics. Detection limits generally lie in the range 100-0.1 ppb (Table 8.4) but these can be improved by chemical pre-concentration procedures involving solvent extraction or ion exchange. 

DETERMINATION OF HEAVY METALS IN ATMOSPHERIC PARTICLES (PM 10 PM 2.5) BY ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY... 

Cruz, R. B. and Loon, J. C. van "A Critical Study of the Application of Graphite-Furnace Non-Flame Atomic Absorption Spectrometry to the Determination of Trace Base Metals In Complex Heavy-Matrix Sample Solutions". Anal. Chlm. Acta (1974), 72, 231-243. 

Fang et al. [661] have described a flow injection system with online ion exchange preconcentration on dual columns for the determination of trace amounts of heavy metal at pg/1 and sub-pg/1 levels by flame atomic absorption spectrometry (Fig. 5.17). The degree of preconcentration ranges from a factor of 50 to 105 for different elements, at a sampling frequency of 60 samples per hour. The detection limits for copper, zinc, lead, and cadmium are 0.07, 0.03, 0.5, and 0.05 pg/1, respectively. Relative standard deviations are 1.2-3.2% at pg/1 levels. The behaviour of the various chelating exchangers used was studied with respect to their preconcentration characteristics, with special emphasis on interferences encountered in the analysis of seawater. 

Yamamoto et al. [33] have studied the differential determination of heavy metals according to their oxidation states by flameless atomic absorption spectrometry combined with solvent extraction with ammonium pyrrolidinedithio-carbamate or sodium diethyldithio-carbamate. 

Klenke et al. [5] described a technique for extraction of humic and fulvic acids from stream sediments and outlined methods for their determination. By means of flame atomic absorption spectrometry, the levels of environmentally important heavy metals (cadmium, copper, chromium, cobalt, nickel and lead) in the fulvic and humic acid extracts were compared with those in the original sediment samples. The pattern distribution of the respective metals in the two cases showed very close agreement, suggesting that the combined extract of humic and fulvic acids could be used as an indicator of the level of heavy metal pollution in flowing waters. 

Soylak, M., L. Elci, and M. Dogan. 2003. Uses of activated carbon columns for solid phase extraction studies prior to determinations of traces heavy metal ions by flame atomic absorption spectrometry. Asian J. Chem. 15 1735-1738. 

Y. Tan, J.-S. Blais, W. D. Marshall, Slurry preparation by high-pressure homogenization for the determination of heavy metals in zoological and botanical certiPed reference materials and animal feeds by electrothermal atomic absorption spectrometry, Analyst, 121 (1996), 1419D1424. 

A water sample requiring heavy metal determination may be evaporated to a smaller volume prior to using atomic absorption spectrometry. 

Uchida, T., Nagase, M., Kojimo, I., lida, C A simple decomposition chelating resin separation for the determination of heavy metals in silicates by atomic absorption spectrometry. Anal. Chim. Acta 94, 275 (1977)... 

Shkinev VM, Gomolitskii VN, Spivakov BY, et al. 1989. Determination of trace heavy metals in waters by atomic-absorption spectrometry after pre-concentration by liquid-phase polymer-based retention. Talanta 36(8) 861-863. 

An important analysis regarding toxicological and legal requirements of flavourings is the control of heavy metal contaminations. Most of the heavy metals show toxic effects in humans, even in trace quantities. Their determination can only be accomplished using trace analysis techniques. In practice, the different analytical techniques Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) have been employed successfully. Both methods require complete dissolution of the sample by decomposition. 

J.H. Wang, E.H. Hansen, M. Miro, Sequential injection—bead injection—lab-on-valve schemes for on-line solid phase extraction and preconcentration of ultra-trace levels of heavy metals with determination by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry, Anal. Chim. Acta 499 (2003) 139. 

To investigate the content of heavy metals approximately 3 g of each investigated sample were prepared by chemical pulping with nitrohydrochloric acid in accordance to the DIN-norm 38414, part 7. The concentration of selected heavy metals (Cu, Cr, Cd, Ni, Pb, Zn) are determined by atom absorption spectrometry with ICP-OES, AAS-FIMS or HGA-AAS -system (Perkin Elmer, Optima 2000 DV). 

The range of off-line instruments available for water analysis Is wide. In fact, any analyser with optical or electrochemical detection can be adapted for this purpose. The use of liquid chromatography for the detection and quantitation of detergents or non-volatile organic compounds, of atomic absorption spectrometry for the analysis for heavy metal traces and of UV spectrophotometry for the determination of phosphates, nitrates and nitrites are representative examples of the potential utilization of conventional analysers for water analysis. 

Z. Fang, J. RdiiCka, and E. H. Hansen, An Efficient Flow-Injection System with On-Line Ion-Exchange Preconcentration for the Determination of Trace Amounts of Heavy Metals by Atomic Absorption Spectrometry. Anal. Chim. Acta, 164 (1984) 23. 

Needleman, H.L, Tuncay, O.C. and Shapiro. I.M. (1972). Lead level in deciduous teeth of urban and suburban American children. Nature 235,111-112 Nordahl, K., Radziuk, B.. Thomassen, Y. and Weberg, R. (1990). Determination of aluminium in human biopsy and necropsy specimens by direct solid sampling cup in tube electrothermal atomic absorption spectrometry, Fres. Z. Anal. Chem. 337, 310-312 Nurnberg, H.W. (1981). in Faccheti, S. (ed.). Analytical techniques for heavy metals in biological fluids, lectures of a course held at the Joint Research Centre, Ispra, Italy, 22-26 June, Elsevier, Amesterdam... 

Based on the principles of precipitate flotation, a rapid and convenient separation technique has been developed for the determination of toxic heavy metals adsorbed on suspended solids in freshwater. Because suspended solids are negatively charged species, they are rendered hydrophobic and coagulate to form bulky floes with a cationic surfactant and sodium chloride (to increase the ionic strength). The floes are easily floated by bubbling and are then treated in nitric acid to determine the desorbed heavy metals (e.g., chromium, manganese, copper, cadmium, and lead) by graphite furnace atomic absorption spectrometry. 

Heavy metals and arsenic Heavy metals are routinely determined, often with one or other form of sulfide precipitation. These compendial tests are performed from the viewpoint of safety and the general limits (l-30pgml g ) are now more often related to the dose. For metals such as mercury, lead, cadmium, or nickel, atomic absorption spectrometry or other instrumental methods are often prescribed. Copper and other transition metals can act as catalysts in certain degradation reactions and thus require special attention. Arsenic tests that were important at the beginning of the previous century are now being phased out. 

M. Tiizen. Determination of heavy metals in fish samples of the middle Black Sea (Turkey) by graphite furnace atomic absorption spectrometry. Food Chemistry 80 119-123, 2003. 

Narin, I., TUzen, M., Soylak, M., 2004. Comparison of sample preparation procedures for the determination of trace heavy metals in house dust, tobacco and tea samples by atomic absorption spectrometry. Anal. Chem. 94, 867. 

Onetti, C.T., Innocent , R., 2009. Determination of heavy metals in textile materials by atomic absorption spectrometry verification of the test method. AUTEX Res. J. 9 (2). 

An example of the application of atomic absorption spectrometry to the determination of heavy metals in polymers is given in Method 1.1 at the end of this chapter. 

Atomic absorption spectrometry is a usefiil technique for the determination of traces of heavy metals in polymers. Generally, the polymer is ashed at a maximum temperature of 450 C to avoid losses of elements by volatilization, then the ash is digested with warm nitric acid prior to spectrometric analysis, (Method 71). 

The need for the determination of metallic constituents or impurities in pharmaceutical products has, historically, been addressed by ion chromatographic methods or various wet-bench methods (e.g. the USP heavy metals test). As the popularity of atomic spectroscopy has increased, and the equipment has become more affordable, spectroscopy-based techniques have been routinely employed to solve analytical problems in the pharmaceutical industry. Table 1 provides examples of metal determinations in pharmaceutical matrices, using spectroscopic techniques, and the reasons why these analyses are important. Flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry... 

Ottaway, J. M. Heavy metals determinations by atomic absorption and emission spectrometry in Analytical Techniques for Heavy Metals in Biological Fluids, (ed.) Facchetti, S., Amsterdam—Oxford—New York Elsevier 1983... 

---