Determination of Micro-amount of Elements in Plant Samples by Inductively Coupled Plasma-Mass Spectrometry with Microwave Digestion

The plant samples were decomposed by microwave digestion using H2O2-HNO3 as solvent.The external standard method was used for calibration.11 micro-amount of elements of B,Cd,Cu,Co,Cr,Mo,Li,Ni,Pb,La and Ge in the plant samples were determined simultaneously by inductively coupled plasma-mass spectrometry(ICP-MS).The parameters for microwave digestion and ICP-MS instrumental operation were optimized by experiments.The interference from organic residues and coexistent ions on determination of Pb,Cd,Ni and the interference eliminating methods were studied.114Cd,10B,65Cu,59Co,52Cr,98Mo,7Li,60Ni,208Pb,139La and 74Ge were chosen as determining isotopes and 103Rh and 45Sc were chosen as internal standards.The detection limits(10SD) of method for 11 elements were in a range of 5 ng/g to 150 ng/g.The method has been validated by determination of these elements in National Standard Reference materials and the results are in agreement with certified values with precision of 1.27% to 5.27%RSD(n=12).The method is suitable for determining these micro-amount of elements in fruits,roots,stems and leaves of different plants.