Correction for non-spectroscopic matrix effects in inductively coupled plasma-mass spectrometry by common analyte internal standardization

The Common Analyte Internal Standardization (CAIS) chemometric technique is extended to correct for non-spectroscopic matrix effects in inductively coupled plasma-mass spectrometry (ICP-MS). The approach is based on using an internal reference element to correct for the matrix effect. Unlike the conventional internal reference method, the CAIS technique allows for the analyte to behave differently from the internal reference under the influence of the matrix. With the CAIS technique a single internal reference element is sufficient to correct for all the analytes. Experimental tests with 13 analytes in four different matrices using different ICP-MS instruments demonstrate that the CAIS is efficient and general for matrix effect correction. Not only is the corrected concentration more accurate, but the precision is significantly better. The capability of CAIS to correct for the effect of a mixture of two matrices was also established experimentally, and 20–30% matrix suppression was eliminated. Furthermore, the developed technique was used as a simple diagnostic quality assurance procedure to evaluate the performance of the mass spectrometer.