NON-SPECTROSCOPIC MATRIX INTERFERENCES IN INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY

Fourteen 0.01 M matrix elements with atomic weight from 7 to 207 (Li, B, Na, K, Cr, Zn, Rb, Mo, Cd, Cs, Sm, Ho, Lu and Pb) have been selected to study their interference effects on analyte (Al, Co, Y, In, La and Tl) signals with a commercial ICP mass spectrometer. The parameters investigated affecting the degree of interference were: mass of matrix element and analyte, ionization potential of matrix element, voltage of the first ion lens element and sampling depth. The matrix effect could not be explained by any single mechanism, e.g. collisions of analyte ions with matrix ions in the supersonic expansion region, space charge effect in the ion optical system and shift in ionization equilibria in the plasma, but by a combination of several mechanisms. © 1990.