ONLINE REMOVAL OF INTERFERENCES IN THE ANALYSIS OF BIOLOGICAL-MATERIALS BY FLOW-INJECTION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

A method of matrix elimination was developed that facilitates the inte rference-free determination of the trace metals vanadium, manganese, c opper, zinc, cadmium and lead in biological matrices by inductively co upled plasma mass spectrometry. The method involves chelation of the a nalytes onto an iminodiacetate-based resin in a microcolumn with simul taneous matrix removal. The analytes are then eluted into the spectrom eter with 3 mol l-1 nitric acid using a flow injection procedure. Anal ysis of certified reference materials yielded results in reasonable ag reement with the certified values. Recovery tests showed close to 100% recoveries for manganese, copper, cadmium and lead, 90% recovery for vanadium and 85% recovery for zinc. The limit of detection (3sigma) fo r these analytes using a 175 mul sample loop ranged from 0.6 to 9.9 ng ml-1 i.e., from 75 to 1800 pg or from 50 to 825 mug kg-1 dry mass of sample. The same chromatographic system was applied to chromium determ inations, but proved unsuccessful.