Electrothermal atomic absorption extraction

COMPARISON OF MICROWAVE ASSISTED EXTRACTION METHODS FOR THE DETERMINATION OF PLATINUM GROUP ELEMENTS IN SOIL SAMPLES BY ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY AFTER PHASE SEPARATION-EXTRACTION... 

Shijo et al. [95] converted bismuth in seawater into its dithiocarbamate complex, and then extracted the complex into xylene prior to determination in amounts down to 0.3 ppt by electrothermal atomic absorption spectrometry. 

The collection behaviour of chromium species was examined as follows. Seawater (400 ml) spiked with 10-8 M Crm, CrVI, and Crm organic complexes labelled with 51Cr was adjusted to the desired pH by hydrochloric acid or sodium hydroxide. An appropriate amount of hydrated iron (III) or bismuth oxide was added the oxide precipitates were prepared separately and washed thoroughly with distilled water before use [200]. After about 24 h, the samples were filtered on 0.4 pm nucleopore filters. The separated precipitates were dissolved with hydrochloric acid, and the solutions thus obtained were used for /-activity measurements. In the examination of solvent extraction, chromium was measured by using 51Cr, while iron and bismuth were measured by electrothermal atomic absorption spectrometry. The decomposition of organic complexes and other procedures were also examined by electrothermal atomic absorption spectrometry. 

In order to overcome the problem of the high nonspecific absorption, alternative procedures have been tested, which involve prior separation of the trace metals from the salt matrix. Examples of extraction of trace metals from seawater as chelates with subsequent determination by electrothermal atomic absorption spectrometric procedures have been described [381,382], but these and similar methods are seldom effective and satisfactory when the matrix is very complex and the analyte concentration very low. 

Chakraborti et al. [665] determined cadmium, cobalt, copper, iron, nickel, and lead in seawater by chelation with diethyldithiocarbamate from a 500 ml sample, extraction into carbon tetrachloride, evaporation to dryness, and redissolution in nitric acid prior to determination by electrothermal atomic absorption spectrometry in amounts ranging from 10 pg (cadmium) to 250 pg (nickel). 

M. Felipe-Sotelo, A. Carlosena, J. M Andrade, E. Fernandez, P. Lopez-Mahia, S. Muniategui and D. Prada, Development of a slurry-extraction procedure for direct determination of cobalt by electrothermal atomic absorption spectrometry in complex environmental samples. Anal. Chim. Acta, 522(2), 2004, 259-266. 

I. Arambarri, R. Garcia and E. Millan, Optimisation of tin determination in aqua regia-HF extracts from sediments by electrothermal atomic absorption spectrometry using experimental design. Analyst, 125(11), 2000, 2084-2088. 

S. Ch. Nielsen, S. Sturup, H. Spliid and E. H. Hansen, Selective flow injection analysis of ultra-trace amounts of Cr(VI), preconcentration of it by solvent extraction and determination by electrothermal atomic absorption spectrometry (ETAAS), Talanta, 49(5), 1999, 1027-1044. 

The sequential extraction of chromium from soils has been studied [89]. A three-step sequential extraction scheme has been proposed using acetic acid, hydroxylamine hydrochloride and ammonium acetate as extracting agents. Steps 1 and 2 were measured by electrothermal atomic absorption spectrometry (ETAAS). Step 3 was measured by flame atomic absorption spectrometry. Interfering effects when measuring chromium in soils were circumvented through the use of a 1% 5-hydroxyquinoline suppressor agent. 

Thomaidis, N.S., A.S. Stasinakis, and T.D. Lekkas. 2007. A screening method for the determination of toluene extractable organotins in water samples by electrothermal atomic absorption spectrometry and rhenium as chemical modifier. Appl. Organometal. Chem. 21 425-433. 

Vaisainen, A. and R. Suontomo. 2002. Comparison of ultrasound-assisted extraction, microwave-assisted acid leaching and reflux for the determination of arsenic, cadmium and copper in contaminated soil samples by electrothermal atomic absorption spectrometry. J. Anal. At. Spectrom. 17 739-742. 

J. Begerow, M. Turfeld, L. Dunemann, Determination of physiological noble metals in human urine using liquid-liquid extraction and Zeeman electrothermal atomic absorption spectrometry, Anal. Chim. Acta, 340 (1997), 277D283. 

J. Cvetkovic, S. Arpadjan, I. Karadjova, T. Stafilov, Determination of thallium in wine by electrothermal atomic absorption spectrometry after extraction preconcentration, Spectrochim. Acta, 57B (2002), 1101-1106. 

P. Hocquellet, M. P. Candiller, Evaluation of microwave digestion and solvent extraction for the determination of trace amounts of selenium in feeds and plant and animal tissues by electrothermal atomic absorption spectrometry, Analyst, 116 (1991), 505-509. 

Lesniewska, B., Kosinska, M., Godlewska-Zyfidewicz, B., Zambrzycka, E., Wilczewska, A. Z. Selective solid phase extraction of platinum on an ion imprinted polymers for its electrothermal atomic absorption spectrometric determination in environmental samples. Microchim. Acta 175, 273-282 (2011)... 

Emteborg H, Bulska E, Freeh W, et al. 1992. Determination of total mercury in human whole blood by electrothermal atomic absorption spectrometry following extraction. J Anal Atomic Spectrom 7(2) 405-408. 

Bavazzano P, Perico A, Rosendahl K, Apostoli P. Determination of urinary arsenic by solvent extraction and electrothermal atomic absorption spectroscopy. I Anal At Spectrom 1996 11 521-4. 

For the homogeneity and stability studies, the trace element contents (Cd, Cr, Cu, Ni, Pb and Zn) were determined by flame atomic absorption spectrometry (FAAS) or electrothermal atomic absorption spectrometry with Zeeman background correction (ZETAAS), strictly following the sequential extraction procedure. Differences between the within-bottle and between-bottle CVs observed for the step 2 were considered to be rather an analytical artefact than an indication of inhomogeneity which would have been reflected in the spread of results submitted in the certification. The material is then considered to be homogeneous for the stated level of intake (1 g). 

For the homogeneity studies, the extractants (0.05 mol L EDTA, 0.43 mol L" acetic acid and 0.005 mol L DTPA) were prepared as laid out in the certification reports [15, 17], The trace element contents (Cd, Cr, Cu, Ni, Pb and Zn) in the extracts were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) for the CRMs 483/484, flame atomic absorption spectrometry (FAAS) or electrothermal atomic absorption spectrometry with Zeeman background correction (ZETAAS) for the CRM 600. In the case of the CRM 483, little analytical difficulty was experienced as illustrated by the good agreement obtained between the within-bottle and between-bottle CVs for the CRM 484, lower extractable contents, closer to the detection limits and consequent poorer analytical precision was observed in particular for Cr (EDTA extractable contents), Cd and Pb (acetic acid extractable contents). No particular difficulties were experienced for the CRM 600. On the basis of these results, the materials were considered to be homogeneous at a level of 5 g for EDTA- and acetic acid-extractable contents and 10 g for DTPA-extractable contents (as specified in the extraction protocols). 

Drasch et al. (1987) examined urine samples for unmetabolized sulfur mustard. Following organic extraction, thin-layer chromatography, and derivativation with gold, the extracts were analyzed using electrothermal atomic absorption spectroscopy. 

Kumpulainen J, Saarela KE. 1992. Determination of selenium in staple foods and total diets by electrothermal atomic absorption spectrometry without solvent extraction. J Anal Atomic Spectr 7(2) 165-170. 

Table 5.3 Conditions employed for the analysis of organotin extracts using electrothermal atomic absorption spectroscopy [15]...

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. 

But there is no specific FAAS standard method specially evaluated or approved for polluted soil samples there is the EPA methods (SW-846 EPA (2000)) or one ISO standard (ISO 11047). This standard is connected with the determination of several metals in aqua regia extracts. It provides a method for the determination of Cd, Cu, Co, Pb, Mn, Ni and Zn by flame and electrothermal atomic absorption spectrometric methods. 

ISO/DIS 20279 Soil quality - Extraction of thallium and determination by electrothermal atomic absorption spectrometry. 

Zheng W, Sipes IG and Carter DE (1993) Determination of parts-per-billion concentrations of indium in biological materials by electrothermal atomic absorption spectroscopy following ion pair extraction. Anal Chem 65 2174-2176. 

Extraction systems with following electrothermal atomic absorption spectroscopy (ET-AAS) may be useful in some cases. For example, Zendelovska and Stafilov (2001) used isoamyl acetate extraction with following ET-AAS for thallium analysis in sulfide minerals. Eleischer (1997) reported a detection limit of 0.8 JgL when using ET-AAS with matrix modification (uirmineralized urine, diluted 1 2). 

Zendelovska D and Stafilov T (2001) Extraction separation and electrothermal atomic absorption spectrometric determination of thallium in some sulfide minerals. Analytical Sciences 17 425 -428. 

Various methods have evolved based on the complexation of monomeric aluminium species with 8-hydroxyquinoline (oxine) and the rapid extraction of the formed Al(oxinate)3 complex into organic solvents, e.g. chloroform [162], toluene [163] or methyl isobutyl ketone (MIBK) [164] detection of the aluminium content was accomplished by electrothermal atomic absorption spectrometry. 

The techniques used to determine metal concentration in extracts were generally FAAS (flame atomic absorption spectrometry) or ETAAS (electrothermal atomic absorption spectrometry). ICP-OES (inductively coupled plasma optical emission spectrometry) and ICP-MS (inductively coupled plasma mass spectrometry) were also used by some laboratories. 

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