Keeping track of evaporating solutions to maintain traceability

Standard solutions are fundamental tools to guarantee traceability in chemical analysis, however, they might suffer solvent evaporation during long storage periods. In this work a measurement model is presented to consider this behaviour and assure the retention of metrological traceability by taking into account solvent evaporation through subsequent weightings at the start and end of the storage period. The proposed iterative formulation is tailored to suit three different experimental setups depending on the available information. Uncertainty budgets based on the proposed models were produced and filled with simulated data to test the contribution of parameters and increment to the combined variance. The results highlighted strengths and drawbacks for each approach but ultimately asserting their suitability within the testing conditions. General considerations were also drawn with recognition of the limitations of the proposed modelisation and the great importance reserved to the knowledge of matrix interactions.