Microwave-assisted extraction and ultrasonic slurry sampling procedures for cobalt determination in geological samples by electrothermal atomic absorption spectroscopy

• Published in: Talanta (Oxford) 2004-06, Vol.63 (3), p.735-742
• Main Authors: Felipe-Sotelo, M, Carlosena, A, Fernández, E, López-Mahı́a, P, Muniategui, S, Prada, D
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemical modifiers; Chemistry; Cobalt; Electrothermal AAS; Exact sciences and technology; Microwave-assisted acid digestion; Soils and sediments; Spectrometric and optical methods; Ultrasonic slurry sampling
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2003.12.029

Slurry sampling is compared to microwave-assisted acid digestion for cobalt determination in soil/sediment samples by electrothermal atomic absorption spectrometry (ETAAS). Furnace temperature programs and appropriate amounts of three chemical modifiers were optimised in order to get the highest signals and good separations between the atomic and background signals. Using nitric acid (0.5% (v/v)) as liquid medium, no chemical modifier was needed. The detection limit, based on integrated absorbance, was 0.04μgg−1 for digests and slurries. Within-batch precision and analytical recoveries were satisfactory for both procedures. Accuracy was tested by analysing a reference soil and a sediment from IRMM. The methods were further compared employing a set of roadside soils and estuarine sediments. As no significant differences (95% confidence) were found, practical analytical properties were suggested in order to select one of them.