Determination of Lead and Cadmium in Grain by Graphite Furnace Atomic Absorption Spectrometry

[Objective]To establish the method of determining lead and cadmium in grain by graphite furnace atomic absorption spectrometry,and observe the effect of simplified digestion on results.[Methods]A total of 0.50 g sample,added with 6.5 ml HNO3 was digested on eclectic cooker,constant volume at 25 ml.The matrix interference was eliminated by adding ammonium dihydrogen phosphate as matrix modifier in graphite oven automatic sampler.[Results]The characteristic mass of lead and cadmium was 10.7 pg and 1.37 pg,respectively,the detection limit was 10 μg/kg and 1.0 μg/kg,respectively.Recovery and precision were 95.9%～105.1% and 1.7%～ 3.4%,respectively.The method passed the blind sample examination of national proficiency-testing program,the analyzed results of reference material matched the result of certificate.[Conclusion]With simplified digestion process,the method can also determine lead and cadmium in grain correctly.