Determination of Lead，Cadmium and Calcium in Plant Hair Dye by GFAAS with Microwave Assisted Sample Digestion

A method for the determination of Pb Cd and Cu in plant hair dye by GFAAS with microwave assisted sample digestion has been set up, using a L₉(3⁴) orthogonal experiment. Effects of the ratio of the sample to digestion solution, ratio of digestion solution, digestion time and digestion pressure were studied. Optimum digestion conditions are: sample/solution (g/ml) 1∶12, HNO₃/H₂O₂(V/V) 4∶1; digestion time, 5 min; and microwave pressure, 1.5 MPa. Under optimum digestion conditions, relative standard deviations were 1.05%～3.35%, average recoveries were 96.67%～105.43%. The results showed that the microwave digestion method is rapid and simple with low reagent consumption and complete digestion, and is of good accuracy and precision.