Continuous Determination of Lead,Chromium and Cadmium in Fruit and Vegetable by Microwave Digestion-Graphite Furnace Atomic Absorption Spectrometry

An effective method was developed for continuous determination of Pb, Cr and Cd in fruit and vegetable by using graphite furnace atomic absorption spectrometry (GFAAS) with microwave digestion. The effects of digestive reagent, digestion time and temperature on sample preparation were discussed, and the determination conditions by GFAAS were optimized. Under the optimum conditions, the linear ranges of Pb, Cr and Cd were 0 to 40μ g/L, 0 to 80μ g/L and 0 to 3μg/L and their detection limits were 0.293 μg/L, 0.037 μg/L and 0.850 μg/L, respectively. The precision relative standard deviations were between 2. 1% and 5.3% for determining the above three elements in flowering Chinese cabbage and snow pear by this method, and the spike recoveries range from 95.0% to 101.9%.