Inductively coupled plasma—mass spectrometry drift correction based on generalized internal references identified by principal components factor analysis

Abstract

Abstract factor analysis is applied to repeated measurements of inductively coupled plasma—mass spectrometry (ICP-MS) responses for several elemental masses in a multielement standard. During good operation, over 90% of the variance in response is accounted for by two or three factors. These factors tend to correlate with different mass ranges, and these correlations allow a rational basis for selection of candidates for internal reference elements. Internal references selected from these candidates were used to evaluate three different mathematical methods for correcting ICP-MS responses of all elements. The line ratio internal reference method and the analyte internal reference correlation method, which use a single internal reference for all elemental masses, improved precisions for most elements but decreased or had no effect on precisions of other elements. The generalized internal reference method, which may use more than one elemental mass in the correction calculation, improved precisions for all elements in most experiments.