POLYATOMIC IONS AS INTERNAL STANDARDS FOR MATRIX CORRECTIONS IN INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

Several strong polyatomic ion signals common in inductively coupled plasma mass spectrometry can be used as internal standards to correct for matrix interferences. Signals for most of the polyatomic ions, including metal oxides, are suppressed by a Cs matrix to the same extent as analyte ion signals at nearby m/z values. Examples include N-14(2)+ and Mg-24(+), (ClO+)-Cl-35-O-16 and Mn-55(+), (ArO+)-Ar-40-O-16 and Co-59(+), (SO+)-S-32-O-16 and Sc-45(+), Ar-40(2)+ and As-75(+), and (YO+)-Y-89-O-16 and Rh-103(+). The count rates for these polyatomic ions are often measured anyway to determine interference corrections for spectral overlap, so these signals should reduce the number of added elements necessary to correct for matrix interferences.