CVG-AAS Determination of Trace Amount of Cadmium in Rice

CVG-AAS was applied to the determinations of cadmium in rice. Sample was digested with mixture of HNO3 and HClO4 (5+1). Gaseous cadmium atom was generated from HCl (5+95) solution by reacting with 25 g·L-1 NaBH4 solution (dissolved in 8 g·L-1 NaOH solution). Flow-rates of 0.8 L·min-1 for the carrier gas was taken in the analysis. Mixed solution of Ni(NO3)2 and thiourea was added to the sample solution as sensitizer. The sample solution was introduced and operated under the prescribed working condition of the instrument. Linear relationship between values of peak area and mass concentration of Cd was found in the range of 0.02-20.0 μg·L-1, with detection limits (3σ) of 0.005 μg·L-1. The proposed method was applied to the analysis of samples of rice, giving values of recovery in the range of 96.7%-103.7%.