Analytical performance of a lab-made concomitant metal analyzer to generate volatile species of Ag, Au, Cd, Cu, Ni, Sn and Zn using 8-hydroxyquinoline as a reaction media

This study evaluated the main parameters affecting Ag, Au, Cd, Cu, Ni, Sn and Zn vapor generation using a lab-made concomitant metal analyzer (CMA) as a reaction chamber and gas–liquid separator. The modifier used in the reaction media was 8-hydroxyquinoline, and Inductively-Coupled Plasma Optical Emission Spectrometry was used as detection technique. The performance of the lab-made concomitant analyzer was compared with the performance of a continuous flow gas–liquid separator and of a cyclonic spray chamber. Standards were prepared in acid media and included 1 mg L−1 of Co as a catalyzer. The optimum concentrations of the reagents in the standards were: 450 mg L−1 of 8-hydroxyquinoline and 0.4 M nitric acid. The optimum concentration of sodium borohydride to generate the vapors was 2.25% (w/v) (prepared in 0.4% (w/v) NaOH). The volatile species were swept from the CMA to the torch by an argon flow of 0.6 mL min−1. The use of the CMA led to an improvement of the detection limits for some elements compared to conventional nebulization: 1.1 μg L−1 for Ag, 7.0 μg L−1 for Au and 4.3 μg L−1 for Sn. The limit of detection for Cu was 1.4 μg L−1 and for Ni 22.5 μg L−1. The direct mixing of the reagents on the spray chamber was not effective for Cd and Zn; a deviation of the linearity was observed for these elements.