Comparative Study of the Main Top-down Approaches for the Estimation of Measurement Uncertainty in Multiresidue Analysis of Pesticides in Fruits and Vegetables

Medina‐Pastor, Paula; Valverde, Antonio; Pihlström, Tuija; Masselter, Sonja; Gamón, M.; Mezcúa, Milagros; Torreblanca, Carmelo Rodríguez; Fernández‐Alba, Amadeo R.

doi:10.1021/jf104060h

Cited by 50 publications

(15 citation statements)

References 21 publications

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“…Therefore, the RSD of the PT was used to estimate U r of the individual methods which successfully participated in PT schemes. The mean RSD of EU-based PT studies for pesticides in fruit and vegetables has ranged at approximately 25% [35, 36]. Therefore the EU member states have adopted a default value of U r = 50% for pesticide residues in food consignment entering the EU [15].…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2018

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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 (Ur). We applied a straightforward procedure for the calculation of Ur from the within-laboratory reproducibility, which is also called intermediate precision, and the uncertainty of RA (ur,RA). To estimate the contribution of the lot-to-lot variation to Ur, 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 Ur. The lot-to-lot variation was contributing to ur,RA and thus to Ur for the majority of the 66 evaluated analytes in both figs and maize. The major contributions of the lot-to-lot variation to ur,RA were differences in analyte recovery in figs and relative matrix effects in maize. Ur was estimated from long-term participation in proficiency test schemes with 58%. Provided proper validation, a fit-for-purpose Ur of 50% was proposed for measurement results obtained by an LC-MS-based multi-mycotoxin assay, independent of the concentration of the analytes.Electronic supplementary materialThe online version of this article (10.1007/s00216-018-1096-5) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2018

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“…The expanded measurement of uncertainties was estimated by applying a “top-down” empirical model (coverage factor k = 2) at a 95% confidence level (Medina-Pastor et al 2011). …”

Section: Methodsmentioning

confidence: 99%

Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities

Wołejko

Kaczyński

Łozowicka

et al. 2017

Environ Monit Assess

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The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg−1) and detection (0.0005 mg kg−1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001–0.5 mg kg−1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT50 of S-MET calculated according to the first-order kinetics model was 11.1–14.7 days (soil) and 9.6–13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.

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“…Method uncertainty (U) for metazachlor and clomazone was calculated following the "top-down" approach using overall recovery and precision data 29,39 , reaching 6-26% (16% on average) for metazachlor and 7-16% (11% on average) for clomazone (coverage factor k = 2, confidence level of 95%). These values are much below the limit value of 50%, recommended by European Union guidelines 35 .…”

Section: Modification and Validation Of Clomazone And Metazachlor Metmentioning

confidence: 99%

The difference in dissipation of clomazone and metazachlor in soil under field and laboratory conditions and their uptake by plants

Szpyrka

Słowik‐Borowiec

Książek

et al. 2020

Sci Rep

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The study concerned dissipation of metazachlor and clomazone, herbicides widely used in rapeseed (Brassica napus L. subsp. napus) protection, applied to the clay soil under field and laboratory conditions. Furthermore, the uptake of these pesticide from soil by rapeseed plants was investigated under field conditions. An additional aim of this work was to modify the QuEChERS method for the determination of metazachlor and clomazone in the plant material. Analytical procedures for metazachlor and clomazone qualification and quantification in rapeseed plants and soil were developed, using gas chromatography with an micro electron capture detector (GC-μECD) and a mass detector (GC-MS/MS QqQ) as confirmation. Dissipation kinetics of herbicide residues in soil were described as first-order equations. The analytical performance was very satisfactory and confirmed that the methods meet the requirements of the European Commission. In the conducted field experiments it was found that dissipation of clomazone and metazachlor in clay soil follows first-order kinetics (R 2 between 0.964 and 0.978), and half-lives were 9.5 days and 10.2 days for clomazone and metazachlor, respectively. Under laboratory conditions, dissipation of clomazone and metazachlor in soil also follows first-order kinetics (R 2 between 0.937 and 0.938), and half-lives were 8.8 days and 5.7 days for clomazone and metazachlor, respectively. Residues of both herbicides in rape plants 22 days after application of herbicides were below the maximum residue levels for Brassica plants. Metazachlor and clomazone dissipate very fast in clay soil and their uptake by rape plants is very low.

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Comparative Study of the Main Top-down Approaches for the Estimation of Measurement Uncertainty in Multiresidue Analysis of Pesticides in Fruits and Vegetables

Cited by 50 publications

References 21 publications

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

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

Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities

The difference in dissipation of clomazone and metazachlor in soil under field and laboratory conditions and their uptake by plants

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