DETERMINATION OF TRACE AMOUNTS OF RARE-EARTH ELEMENTS IN TOBACCO BY ICP-MS WITH MICROWAVE ASSISTED SAMPLE DIGESTION

A method for the determination of trace amounts of rare earth elements in tobacco by ICP-MS with microwave assisted sample digestion was developed.Binary internal standards of 115In-103Rh were selected to compensate the drift of analytical signals.Multiatomic ion interference were calibrated by measuring the signal of oxides (MO+) and hydroxide (MOH+) with individual element (as La,Ce,Pr and Ba solution ) for the ratio of MO+/M+ and MOH+/M+ and calculating interference correction coefficients.The proposed method has been applied to the analysis of plant standard Reference Materials GSV-1 (bush branches and leaves),GSV-2 (bush branches and leaves),GSV-3 (poplar leaves) and GSV-4 (tea leaf).The relative standard deviations are better than 15%.The Detection limits (DL) and Quantitation limits (QL) were in the range of 0.7-2.5 ng·L-1,0.1-0.49 ng·g-1,respectively.The analysis of tobacco for different plantation area in Hubei province showed that the distribution and fractionation of REEs were related to the environment of local soil.These phenomena are good in agreement with character of soil in Hubei province.The proposed method would be useful to identify and verify the origin of tobacco.