Electrothermal atomization cobalt

Atomic absorption spectrometry has been used to determine caesium in seawater. The method uses preliminary chromatographic separation on a strong cation exchange resin, ammonium hexcyanocobalt ferrate, followed by electrothermal atomic absorption spectrometry. The procedure is convenient, versatile, and reliable, although decomposition products from the exchanger, namely iron and cobalt, can cause interference. 

Jin [666] used ammonium pyrrolidine dithiocarbamate and electrothermal atomic absorption spectrometry to determine lead, cadmium, copper, cobalt, tin, and molybdenum in seawater. 

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). 

Chang et al. [952] used a miniature column packed with a chelating resin and an automatic online preconcentration system for electrothermal atomic absorption spectrometry to determine cadmium, cobalt, and nickel in seawater. Detection limits of 0.12,7 and 35 ng/1 were achieved for cadmium, cobalt, and nickel, respectively, with very small sample volume required (400-1800 xl). 

The elements covered are aluminium, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, vanadium, and zinc. Electrothermal atomic absorption and anodic and cathodic scanning voltammetric methods are discussed. 

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. 

B. S. Iversen, A. Panayi, J. P. Camblor and E. Sabbioni, Simultaneous determination of cobalt and manganese in urine by electrothermal atomic absorption specttrometry. Method development using a simplex optimisation approach, J. Anal. At. Spectrom., 11(8), 1996, 591-594. 

In 140 water samples from the river Saale, sampled from 1986 to 1988 according to the technique described in Section 8.1.1.1, the heavy metals iron and zinc were determined using flame AAS and lead, cadmium, chromium, cobalt, copper, and nickel by AAS with electrothermal atomization in the soluble fraction (particle diameter <0.45 pm). The sampling points, located in Thuringia (Germany), are illustrated in Fig. 8-7. The method of standard addition, with three additions, was used to minimize matrix effects. The components ammonium, chloride, magnesium, nitrate, nitrite, phosphate, oxygen,... 

Cobalt ultra-trace On-line preconcentration and determination using a PTFE turnings packed column and electrothermal atomic absorption spectrometry. Applications in natural waters and biological samples. J Anal Atom Spectrom 17 1330-1334. 

Alvarado, J. and A.R. Cristiano Determination of cadmium, cobalt, iron, nickel, and lead in Venezuelan cigarettes by electrothermal atomic absorption spectrometry ... 

Andersen, I. and Hogetveit, A.Chr. (1984). Analysis of cobalt in plasma by electrothermal atomic absorption spectrometry. Fresenius Z. Anal. Chem., 318, 41. 

Simultaneous determination of cobalt and manganese in urine by electrothermal atomic absorption spectrometry. Extraction procedure optimised using simplex. 

Atomic absorption spectrometry (AAS) has been used to determine cationic and anionic surfactants indirectly. Two methods have been put forward based on the formation of the ion pair between surfactant and hexanitrocobaltate (for cationic compounds) or bis(benzoyl)pyridine thiosemicarbazone cobalt (III) (for anionic compounds). In the former case, the complex is extracted with 1,3-dicloroethane and in the latter with an isopentylacetate and isopentyl alcohol mixture. Concentration of cobalt is determined in the organic phase using electrothermal atomic absorption spectroscopy (ETAAS), while for anionic surfactants, flame atomic absorption spectroscopy (FAAS) can also be used. Interferences like metal ions, anions and organic compounds do not have a great relevance. The two methods were applied to determine dodecyltrimethylammonium bromide in shampoos (Chattaraj and Das, 1992) and sodium lauryl sulfate (SDS) in toothpastes (Chattaraj and Das, 1994). 

Yuzefovsky et al. [241] used Cis resin to preconcentrate cobalt from seawater prior to determination at the ppt level by laser-excited atomic fluorescence spectrometry with graphite electrothermal atomiser. 

Flameless atomic absorption using an electrothermal atomiser is essentially a non-routine technique requiring specialist expertise. It is slower than flame analysis only 10—20 samples can be analysed in an hour furthermore, the precision is poorer (1—10%) than that for conventional flame atomic absorption (1%). The main advantage of the method, however, is its superior sensitivity for any metal the sensitivity is 100—1000 times greater when measured by the flameless as opposed to the flame technique. For this reason flameless atomic absorption is employed in the analysis of water samples where the flame techniques have insufficient sensitivity. An example of this is with the elements barium, beryllium, chromium, cobalt, copper, manganese, nickel and vanadium, all of which are required for public health reasons to be measured in raw and potable waters (section I.B). Because these elements are generally at the lOOjugl-1 level and less in water, their concentration is below the detection limit when determined by flame atomic absorption as a result, an electrothermal atomisation (ETA) technique is often employed for their determination. 

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