SIMULTANEOUS DETERMINATION OF CADMIUM AND MERCURY IN FOOD BY MICROWAVE DIGESTION ATOMIC FLUORESCENCE SPECTROMETRY

[Objective] To establish a rapid and sensitive method for simultaneous determination of cadmium and mercury in food samples by atomic fluorescence spectrometry. [Methods] Microwave-digestion technique with HNO3-H2O2 was applied for the pretreatment of samples. The sample pretreatment and instrumental operation parameters were optimized. The experimental reaction system and reaction conditions were optimized, respectively. The influence from co-existing foreign ions and the elimination were also studied. [Results] Under the optimized conditions, the linear range of the method was 0.2-4.0μg/L for cadmium and mercury with the correlation coefficients of 0.999 4 for cadmium and 0.999 9 for mercury. The detection limits of cadmium and mercury were 0.007μg/and 0.032μg/L, respectively. The quantification limits were 0.022μg/L for cadmium and 0.105μg/L for mercury. The RSD were in the range of 1.65%-4.8% for cadmium and 1.0%-5.1% for mercury. The spiked recoveries of the analytical method were 97.0%-119.5% for cadmium, and 88.5-104.0% for mercury. [Conclusion] The method is simple, rapid, accurate and sensitive. It can be adopted for simultaneous determination of cadmium and mercury in food samples.