GFAAS Determination of Lead in Soy Sauce

The sample of soy sauce was pretreated by microwave assisted sample digestion,and lead in the sample solution was determined by GFAAS. Interference of NaCl in sample solution was offset by addition of nearly same amount of NaCl to the standard solutions in preparation of standard curve. Mixed solution of NH4H2PO4 and Mg(NO3)2 was used as matrix modifier. Linear relationship between values of absorbance and mass concentration of lead was obtained in the range of 5.0-40.0 μg·L-1,with detection limit (3s/k) of 16pg and RSD (n=7) of 3.32%. The proposed method was used to the analysis of soy sauce,giving values of recovery in the range of 91.0%-98.6%.