Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

Abstract

Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samatium, europium, t sr b' ium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in partsper-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values.These values were compared with results 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. DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor my of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. INTR0DC:CTIONAs a result of ongoing industrial pollution and the vital role of plants in the food chain, interest has increased in the ability of plants to uptake potentially hazardous heavy metals from their surroundings. Much attention has also been given to the field of radiological safety, including the determination of small amounts of actinide elements in botanical tissues, as a component of individual contamination-monitoring problems (1). Because environmental samples have large amounts of organic matrix elements but may have low concentrations of the rare earth elements, a digestion procedure whereby the organic matrix is oxidized, leaching the metals from the matrix, must be coupled with an instrumental technique with characteristically low limits of detection.Problems typically arising from the determination of elements in environmental samples are not associated with the efficiency of the instrumental method, but rather ...

The relationship of mineral and geochemical composition to artificial radionuclide partitioning in Yenisei river sediments downstream from Krasnoyarsk

“…The calculation of the content of organic substances in the bottom sediment samples was made using formula (Alvarado et al 1996):…”