An improved semiquantitative method for elemental analysis of plants using inductive coupled plasma mass spectrometry

A semiquantitative ICP-MS method suitable for evaluating metal content in plants exposed to high metal concentrations is described. The methodology which has been tested using different plant reference material is able, in only a few minutes, to obtain qualitative and quantitative information from the sample. Recoveries close to 100% were obtained for more than half of the referenced elements with an RSD <10%, thus avoiding the generation of a calibration line for each of the elements to be analyzed. The use of multi-standards improves the results obtained with conventional standards by a factor of two. In these conditions the semiquantitative multi-elemental analysis is a valid alternative for most of the analyzed elements with the exception of Si, Al, and P which requires the use of a quantitative ICP-MS analysis for its determination. Two different digestion protocols were tested, with and without the addition of HF to the HNO(3) + H(2)O(2) extraction mixture. Similar results were obtained for poplar and bush reference materials using the HNO(3) + H(2)O(2) mixture. The addition of HF did not improve the recovery of different elements, in general, but is critical for the quantitative measurements of Al and Si as its presence allows results to be obtained with an RDS <5%.