ONLINE STANDARD ADDITION METHOD WITH ICPMS USING FLOW-INJECTION

A single-line flow injection manifold was used to perform the standard addition method on-line with ICPMS. The proposed approach requires in jection of the sample into two different carriers (i.e., a blank and a standard with a greater concentration than that of the sample), as we ll as injection of the standard in the blank carrier, The method takes into account the change in sensitivity induced by the sample upon its injection into the standard carrier, Zn the best conditions, one repl icate multielemental analysis by the on-line standard addition method was accomplished in 200 s (using 100-mu L injections), Furthermore, th e setup induced only limited dispersion (i.e., the dispersion coeffici ent was between 1.2 and 2) and therefore provided sensitivity similar to that expected from direct continuous nebulization of the sample, Al though precision was poorer than that which is typical of, for instanc e, external calibration, the proposed method adequately compensated fo r the effect of a 0.01 M K matrix, allowing the accurate determination of V, Co, Ni, Cu, Zn, Mo, Cd, Sb, and Pb in this matrix, The method w as also successfully applied to the direct determination of Mo in seaw ater.