MICROWAVE DISSOLUTION OF PLANT-TISSUE AND THE SUBSEQUENT DETERMINATION OF TRACE LANTHANIDE AND ACTINIDE ELEMENTS BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

Recently there has been much concern about the ability of plants to up take heavy metals from their surroundings. With the development of ins trumental techniques with low detection limits, such as inductively co upled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic materi al inherent in environmental samples. Closed-vessel microwave dissolut ion was compared with conventional methods for the determination of co ncentrations of cerium, samarium, europium, terbium, uranium, and thor ium in a series of samples from the National Institute of Standards an d Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots ov er three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave di gestion system for the analysis of reference materials showed close ag reement with the accepted values. These values were compared with resu lts obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported.