Chemical vapor generation by reaction of cadmium with potassium tetrahydroborate and sodium iodate in acidic aqueous solution for atomic fluorescence spectrometric application

Abstract

In the traditional chemical vapor generation system of KBH₄ (or NaBH₄)–Cd²⁺–HCl in aqueous solution, volatile components containing cadmium species can be generated but with low efficiency. In this work, it was found for the first time that the efficiency for the generation of the cadmium-containing vapor was greatly improved when halogenate, i.e., NaBrO₃ or NaIO₃, was added. The chemically generated vapor was separated from the reaction medium, and introduced into an atomic fluorescence spectrometer (AFS) with argon as the carrier gas, for the atomization and detection of cadmium. The experimental conditions for the efficient generation of the cadmium-containing vapor were optimized and the limit of detection (LOD, 3σ) was then found to be 10 pg mL⁻¹. This modified chemical vapor generation system is potentially cleaner, and could have wide applications for sample introduction and/or matrix separation in analytical atomic spectrometries, such as flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma atomic emission spectrometry (ICP-AES), ICP-MS (mass spectrometry), microwave induced plasma atomic emission spectrometry (MIP-AES) and MIP-MS for the determination of ultratrace cadmium or some other elements.