Determination of cadmium and lead in edible oils by electrothermal atomic absorption spectrometry after reverse dispersive liquid-liquid microextraction

摘要

The dispersive liquid-liquid microextraction of edible oils with a low volume of an acidic solution in the presence of isopropyl alcohol allows cadmium and lead to be completely separated into the aqueous phase. After centrifugation, the metals are determined by electrothermal atomization atomic absorption spectrometry using a palladium salt for chemical modification in the heating cycle. Using a 10 g oil sample, the enrichment factor is 140, which permits detection limits of 0.6 and 10 ng kg~(-1) for cadmium and lead, respectively. The results agree with those obtained after sample mineralization. Data for the cadmium and lead levels for 15 samples of different characteristics are given.