Validation and measurement uncertainty of rapid and simultaneous determination of 19 elements in drinking water using ICP-MS

Abstract

A sensitive, rapid and reliable method was developed and validated for the quantitative determination of 19 elements (31 elemental isotopes) in drinking water using inductively coupled plasma–mass spectrometry. A commercial drinking water matrix was used for conducting method validation in terms of selectivity, limit of detection, limit of quantification, sensitivity, linearity, working range, trueness, precision and measurement uncertainty. Validation parameters are briefly discussed and assessment criteria have been set. In the case of linearity, residual percentage of all elemental isotopes fell in the acceptance range of 80 % –120 % from the expected concentration, with r² greater than 0.990 except for ⁹⁸Mo, for which r² was 0.986. In terms of trueness, recoveries for all elemental isotopes fell in the acceptable range of 80 %–120 % except for ¹¹B for which recovery was 122 %. In terms of precision, repeatability of the analytical method ranged from 0.45 % for ⁶³Cu to 6.75 % for ⁷⁸Se while in case of within laboratory reproducibility it ranged from 1.07 % for ⁶⁵Cu to 10.53 % for ²⁷Al. In addition, expanded uncertainty ranged from 3.5 % for ⁶³Cu to 24.8 % for ²⁷Al. Traceability of the measurement results was established based on the use of certified ICP Multi-element standard solutions and by analyzing spiked samples. It can be concluded that the described analytical procedures to measure the mass concentrations of 19 elements in drinking water samples with established traceability and evaluated uncertainty can provide reliable and internationally comparable results.