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The contribution of lot-to-lot variation to the measurement uncertainty of an LC-MS-based multi-mycotoxin assay.

ABSTRACT: Multi-mycotoxin determination by LC-MS is commonly based on external solvent-based or matrix-matched calibration and, if necessary, the correction for the method bias. In everyday practice, the method bias (expressed as apparent recovery RA), which may be caused by losses during the recovery process and/or signal/suppression enhancement, is evaluated by replicate analysis of a single spiked lot of a matrix. However, RA may vary for different lots of the same matrix, i.e., lot-to-lot variation, which can result in a higher relative expanded measurement uncertainty (U _r ). We applied a straightforward procedure for the calculation of U _r from the within-laboratory reproducibility, which is also called intermediate precision, and the uncertainty of RA (u_r,RA). To estimate the contribution of the lot-to-lot variation to U _r , the measurement results of one replicate of seven different lots of figs and maize and seven replicates of a single lot of these matrices, respectively, were used to calculate U _r . The lot-to-lot variation was contributing to u_r,RA and thus to U _r for the majority of the 66 evaluated analytes in both figs and maize. The major contributions of the lot-to-lot variation to u_r,RA were differences in analyte recovery in figs and relative matrix effects in maize. U _r was estimated from long-term participation in proficiency test schemes with 58%. Provided proper validation, a fit-for-purpose U _r of 50% was proposed for measurement results obtained by an LC-MS-based multi-mycotoxin assay, independent of the concentration of the analytes.

SUBMITTER: Stadler D

PROVIDER: S-EPMC6021480 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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The contribution of lot-to-lot variation to the measurement uncertainty of an LC-MS-based multi-mycotoxin assay.

Stadler David D Sulyok Michael M Schuhmacher Rainer R Berthiller Franz F Krska Rudolf R

Analytical and bioanalytical chemistry 20180501 18

Multi-mycotoxin determination by LC-MS is commonly based on external solvent-based or matrix-matched calibration and, if necessary, the correction for the method bias. In everyday practice, the method bias (expressed as apparent recovery RA), which may be caused by losses during the recovery process and/or signal/suppression enhancement, is evaluated by replicate analysis of a single spiked lot of a matrix. However, RA may vary for different lots of the same matrix, i.e., lot-to-lot variation, w ...[more]

PMID: 29713754

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Project description:Exposure to natural food contaminants during infancy may influence health consequences later in life. Hence, breast milk may serve as a vehicle to transport these contaminants, including mycotoxins, from mothers to their infants. Analytical methods mostly focused on single exposures in the past, thus neglecting co-occurrences and mixture effects. Here, we present a highly sensitive multi-biomarker approach by a sophisticated combination of steps during sample preparation including a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction followed by a solid phase extraction (SPE) cleanup and utilizing stable isotopes for compensating challenging matrix effects. The assay was validated in-house, reaching limits of detection (LOD) for all 34 analytes in the range of 0.1 to 300 ng/L with satisfying extraction efficiencies (75-109%) and stable intermediate precisions (1-18%) for most analytes. Compared to a similar multi-mycotoxin assay for breast milk, LOD values were decreased by a factor of 2-60x enabling the assessment of chronic low-dose exposures. The new method was applied to a small set of Nigerian breast milk samples (n = 3) to compare results with already published data. Concentration levels of samples that were found to be contaminated before could be confirmed. In addition, other mycotoxins were determined in all three samples, for example the newly investigated alternariol monomethyl ether (AME) was found for the first time in this biological fluid at concentrations up to 25 ng/L. Moreover, in a pooled Austrian sample obtained from a milk bank, trace amounts of multiple mycotoxins including AME (1.9 ng/L), beauvericin (5.4 ng/L), enniatin B (4.7 ng/L), enniatin B1 (<LOQ), ochratoxin A (<LOQ) and the estrogenic zearalenone (<LOQ) confirmed co-occurrence and exposure even in a country with high food safety standards. In conclusion, the method facilitates the determination of mycotoxins at ultra-trace levels in breast milk, enabling the generation of occurrence data necessary for comprehensive co-exposure assessment.

Dataset Information

The contribution of lot-to-lot variation to the measurement uncertainty of an LC-MS-based multi-mycotoxin assay.

Publications

The contribution of lot-to-lot variation to the measurement uncertainty of an LC-MS-based multi-mycotoxin assay.

Similar Datasets

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