Determination of As, Cd and Hg in emulsified vegetable oil by flow injection chemical vapour generation inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of As, Cd and Hg in vegetable oils using flow injection vapour generation (VG). An oil emulsion containing 10% m/v vegetable oil, 2% v/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of As, Cd and Hg. The quanti. cations have been carried out using standard addition and isotope dilution methods. The influences of vapour generation conditions and emulsion preparation on the ion signals were reported. This method has been applied for the determination of As, Cd and Hg in soybean oil and peanut oil samples obtained from a local market. The analytical results of various vegetable oil samples determined by standard addition and isotope dilution methods were in good agreement with those of digested samples analysed by pneumatic nebulization ICP-MS. Under the optimum operating conditions, the detection limit obtained from the standard addition curve was 0.01, 0.04 and 0.04 ng g(-1) for As, Cd and Hg, respectively, in the original oil samples.