Novel solid sampling electrothermal vaporization atomic absorption spectrometry for fast detection of cadmium in grain samples

• Published in: Journal of analytical atomic spectrometry 2021-02, Vol.36 (2), p.285-293
• Main Authors: Xing, Peizhe, Li, Xue, Feng, Li, Mao, Xuefei
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Acid digestion; Atomic absorption analysis; Fillers; Kaolin; Oxidation; Pyrolysis; Sampling methods; Scientific imaging; Spectrometry; Vaporization
• ISSN: 0267-9477; 1364-5544
• DOI: 10.1039/d0ja00387e

In this work, a novel solid sampling method of Cd in grain samples was established based on electrothermal vaporization atomic absorption spectrometry (ETV-AAS). The solid sampling system was mainly composed of a quartz ETV tube, a pyrolysis furnace with a kaolin filler, an integrated outlet tube (IOT), an AAS detector and a gas generation system. The gas system generated oxidizing (containing O 2 ) and reducing (containing H 2 and N 2 ) atmospheres, in that order, from only air and water to ash the sample and vaporize and transport Cd, respectively. After drying at 350 °C for 20 s and ashing at 350-725 °C for 55 s under a 300 mL min −1 air atmosphere, ∼4.5% Cd was pre-vaporized and then captured by the kaolin filler at 700-850 °C; when H 2 was introduced at 350 mL min −1 to react with O 2 in the air to yield a N 2 /H 2 atmosphere, Cd in the sample residue and that captured on the filler were completely vaporized from 725 °C to 800 °C (50 s ETV) and then detected by N 2 /H 2 flame AAS. Under optimum conditions, the detection limit (LOD) was 0.03 ng with