Photometric Determination of Cadmium in Materials for Producing Cigarettes with Solid Phase Extraction

Cadmium(Ⅱ) in samples of materials for producing cigarettes was separated and enriched by passing through anionic-exchange SPE column. Cadmium in the extract was reacted with the chromogenic reagent 6-bromo-2-benzothiazolyl diazoaminoazobenzene (BBTDAA) as chromogenic reagent. In a Na2B4O7-NaOH buffer solution of pH 10, and in the presence of Triton X-100, a stable coordination complex with the molar ratio ［Cd(Ⅱ)∶BBTDAA］ of 1 to 2 was formed, with its absorption maximum at the wavelength of 520 nm. Value of apparent molar absorptivity was found to be 1.92×105L·mol-1·cm-1. Beer′s law was kept in the range within 1.0 mg·L-1. The proposed method was applied to the analysis of samples of materials for producing cigarettes, giving results in consistency with those obtained by AAS. Values of RSD′s (n=8) found were in the ranges of 2.2%-2.8%.