MULTIELEMENT ANALYSIS USING FLOW-INJECTION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY - ANALYTICAL ASPECTS OF MULTIELEMENT DETERMINATIONSIN HIGHLY CONCENTRATED-SOLUTIONS OF PHOSPHORIC-ACID, SODIUM-PHOSPHATEAND SODIUM-NITRATE

Trace element concentrations of 51 elements in a single matrix solutio n consisting of 15% (m/m) H3PO4, 16% (m/m) NaNO3 and 6% (m/m) Na3PO4 h ave been determined by flow injection inductively coupled plasma mass spectrometry (FI-ICP-MS) using an addition calibration method. The tec hnique was routinely applied without suffering from the instrumental d rawbacks normally experienced with the continuous aspiration of highly concentrated solutions. The influence of matrix-induced polyatomic sp ecies was investigated by calculating all polyatomic species possibly present in the argon plasma and by determining their interference equi valent concentrations by means of a synthetic sample. The dwell time p er isotope monitored was optimized using the tanks-in-series model wit h which an excellent fit of the experimentally determined flow injecti on signal was obtained. The detection limits in the actual matrix were derived from the standard deviations of the low (< 5 ng/ml) element c oncentrations and were in the order of magnitude 1-2 ng/ml, which was sufficient for the purposes addressed.