Estimation of the uncertainty in a multiresidue method for the determination of pesticide residues in fruit and vegetables

Abstract

The estimation of uncertainty of an analytical result has become important in analytical chemistry. It is especially difficult to determine uncertainties for multiresidue methods, e.g. for pesticides in fruit and vegetables, as the varieties of pesticide/commodity combinations are many. In the present study, recommendations from the International Organisation for Standardisation's (ISO) Guide to the Expression of Uncertainty and the EURACHEM/CITAC guide Quantifying Uncertainty in Analytical Measurements were followed to estimate the expanded uncertainties for 153 pesticides in fruit and vegetables. Data from in-house validation were used in the estimation of the uncertainty. No significant difference in the relative standard deviation for reproducibility (RSD(R)) were found between the different concentration levels at concentration levels exceeding 2.5 times the detection limit. Therefore, it was possible to pool the RSD(R) within a single matrix. However, a difference in RSD(R) between matrices was seen, thus the poorest RSD(R) of the investigated matrices was chosen for the uncertainty estimation. The expanded uncertainties ranged from 7 to 78% with an average of 32% and median of 32%. Furthermore, only RSD(R) contributed to the uncertainty estimation.

Survey of pesticide residues in table grapes: Determination of processing factors, intake and risk assessment

“…A four-step procedure, using data from the in-house validation (top-down approach), was used in the quantification of the uncertainty (Christensen et al 2003b). Limits of determination were calculated as six times the standard deviation of seven spiked samples.…”

Measurement Uncertainty Associated with Sample Processing of Oranges and Tomatoes for Pesticide Residue Analysis

“…Data for the calculation of measurement uncertainty are mostly derived from in-house validation (5,6) or proficiency test studies (7), involving the analysis of spiked homogenized analytical portions. Consequently, one of the largest sources of errors, sample processing, is not taken into account.…”

Application of a Straightforward Methodology by LC-QqQ-MS/MS and GC-MS to Ensure Food Safety of Barley and Wheat Grain

“…As reported by Christensen et al, 50 the advantage of using method validation data for the uncertainty estimation is that the number of contributions to the uncertainty can be reduced to a minimum. Medina-Pastor et al 51 suggest that the U′ should be revised during the ongoing validation of the method, as the longer the period for which the data, the more realistic are the result.…”