Component of the matrix that embodies an influence quantity.
Example:
In the analysis of arsenic using inductively coupled plasma-mass spectrometry at low mass resolution, the presence of chloride in the analytical sample causes the formation of \(\ce{^{40}Ar^{35}Cl^{+}}\) which has the same \(m/z\) value of 75 as \(\ce{As^{+}}\).
Source:
PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1006 (https://doi.org/10.1515/pac-2019-0819)