Comparative assessment of measurement uncertainty for ICP-MS determination of platinum and palladium in ore using tolerance intervals and ISO 11352

Abstract Accurate determination of platinum (Pt) and palladium (Pd) in ore matrices remains analytically challenging due to matrix complexity, spectral interferences, and the ultra-trace concentrations at which these elements naturally occur. This work presents the development and full validation of an inductively coupled plasma mass spectrometry (ICP-MS) method for the simultaneous quantification of Pt and Pd in ore samples, using lead fire assay with cupellation as the preconcentration step. Validation was performed using a β-content, γ-confidence tolerance interval strategy, which integrates method validation and measurement uncertainty estimation into a single coherent framework, without requiring additional experimental data beyond routine validation work. A simple linear regression calibration model was selected based on systematic evaluation of uncertainty profiles across the working concentration range. Trueness, expressed as relative bias, did not exceed − 2.03% for either element at any concentration level, and recovery was within the predefined acceptance criteria of ± 15%. Measurement uncertainty was subsequently assessed using two complementary top-down approaches: the uncertainty profile method and the ISO 11352 framework. Statistical comparison by Fisher’s F-test demonstrated that the two approaches yield statistically equivalent uncertainty estimates when the proportion β is set to 90% or 95%, establishing this threshold as the minimum requirement for reliable prediction of routine analytical performance from validation data. These findings confirm that the uncertainty profile approach constitutes a practical and resource-efficient alternative to ISO 11352 for laboratories involved in platinum-group element analysis, enabling simultaneous method validation and uncertainty characterization from a single experimental dataset.