Online Standard Addition Method with ICPMS Using Flow Injection

Abstract

A single-line flow injection manifold was used to perform the standard addition method on-line with ICPMS. The proposed approach requires injection of the sample into two different carriers (i.e., a bulk and a standard with a greater concentration than that of the sample), as well 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. In the best conditions, one replicate multielemental analysis by the on-line standard addition method was accomplished in 200 s (using 100-μL injections). Furthemore, the setup induced only limited dispersion (i.e., the dispersion coefficient was between 1.2 and 2) and therefore provided sensitivity similar to that expected from direct continuous nebulization of the sample. Although precision was poorer than that which is typical of, for instance, external calibration, the proposed method adequately compensated for 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 was also successfully applied to the direct determination of Mo in seawater