Determination of cadmium in aqueous media by flow injection cold vapour atomic absorption spectrometry. Application to natural water samples

A simple, sensitive and rapid flow injection system for Cd cold vapour generation coupled to atomic absorption spectrometry (FI-CV-AAS) was developed. A vesicular medium of didodecyldimethylammonium bromide (DDAB) was investigated in order to understand the possible mechanisms occurring in Cd cold vapour generation and the influence of this surfactant as a catalyst. Similar experiments in an aqueous medium were carried out with optimization of the physical and chemical parameters. Identical analytical characteristics such as linearity and precision, and similar detection limits (0.15 and 0.05 mu g l(-1) for DDAB and aqueous media, respectively), were found for both reaction media; hence, the use of surfactants was not necessary for Cd cold vapour generation. Validation of the method was carried out by determining the Cd content in several certified waters. The method was applied to the analysis of some natural waters by the standard additions calibration method.