Determination of cadmium in rice bran oils by ICP-MS with rapid ultrasound-assisted acid leaching extraction

As an important byproduct of rice bran in the rice milling industry, rice bran oil (RBO) has become increasingly popular in daily diets in recent years. Cadmium (Cd) is a toxic element and easily accumulates in rice bran; thus, it is of great significance to investigate Cd occurrence in RBOs for the sake of public health. In this study, an ultrasound-assisted extraction procedure method using diluted acid followed by inductively coupled plasma mass spectrometry was developed for the determination of Cd in RBOs. Key parameters that affect the ultrasound-assisted extraction of Cd, namely, ultrasonic power, acid extractant, extractant/oil ratio and sonication time, were investigated in detail. Under the optimized extraction conditions with inductively coupled plasma mass spectrometry (ICP-MS) determination, a limit of detection of 0.08 ng g −1 , a precision of 5.1%, and recoveries in the range of 97–102% were achieved for the determination of Cd in RBOs. The proposed method is simple, fast and accurate and was applied to analyze RBOs available on the market. The survey showed that the Cd residue was very low, so consumption of RBOs does not pose a risk regarding Cd exposure.