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Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce.

Mol HG, Rooseboom A, van Dam R, Roding M, Arondeus K, Sunarto S - Anal Bioanal Chem (2007)

Bottom Line: The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades.The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person.Validation data for 341 pesticides and degradation products are presented.

View Article: PubMed Central - PubMed

Affiliation: Rikilt Institute of Food Safety, Pesticides and Contaminants, P.O. Box 230, 6700 AE, Wageningen, The Netherlands. hans.mol@wur.nl

ABSTRACT
The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary-secondary amine and graphitized carbon black) and large-volume (20 muL) injection. The same extract, before clean-up and after a change of solvent, was also analyzed by liquid chromatography with tandem mass spectrometry (LC-MS-MS). All aspects related to sample preparation were re-assessed with regard to ease and speed of the analysis. The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades. The modifications were made with techniques currently commonly applied in routine laboratories, GC-MS and LC-MS-MS, in mind. The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person. Limits of quantification (LOQs) of 0.01 mg kg(-1) were achieved with both GC-MS (full-scan acquisition, 10 mg matrix equivalent injected) and LC-MS-MS (2 mg injected) for most of the pesticides. Validation data for 341 pesticides and degradation products are presented. A compilation of analytical quality-control data for pesticides routinely analyzed by GC-MS (135 compounds) and LC-MS-MS (136 compounds) in over 100 different matrices, obtained over a period of 15 months, are also presented and discussed. At the 0.05 mg kg(-1) level acceptable recoveries were obtained for 93% (GC-MS) and 92% (LC-MS-MS) of pesticide-matrix combinations.

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Typical extracted ion chromatograms obtained by LC–MS–MS analysis of vegetable and fruit extracts (calibration standard in mango matrix, 10 pg μL, corresponding to 0.05 mg kg−1)
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Fig5: Typical extracted ion chromatograms obtained by LC–MS–MS analysis of vegetable and fruit extracts (calibration standard in mango matrix, 10 pg μL, corresponding to 0.05 mg kg−1)

Mentions: In the same way as for GC–MS analysis, the initial validation data are continually being supplemented by performance data generated as part of analytical quality control during routine analysis of samples. With each set of analytical samples at least one was fortified with the full quantitative suite (i.e. 136 pesticides and degradation products) at the 0.05 mg kg−1 level. A compilation was made from all the data generated over a period of 12 months, which included data for more than one hundred vegetable and fruit matrices. A limited number of dry matrices (flour, milk powder) were also included in the set. The data were evaluated for one transition for each pesticide, using the API3000 and injection of 2 mg equivalent of matrix (10 μL of a 0.2 g mL−1 extract). Examples of typical extracted ion chromatograms are shown in Fig. 5.Fig. 5


Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce.

Mol HG, Rooseboom A, van Dam R, Roding M, Arondeus K, Sunarto S - Anal Bioanal Chem (2007)

Typical extracted ion chromatograms obtained by LC–MS–MS analysis of vegetable and fruit extracts (calibration standard in mango matrix, 10 pg μL, corresponding to 0.05 mg kg−1)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2117333&req=5

Fig5: Typical extracted ion chromatograms obtained by LC–MS–MS analysis of vegetable and fruit extracts (calibration standard in mango matrix, 10 pg μL, corresponding to 0.05 mg kg−1)
Mentions: In the same way as for GC–MS analysis, the initial validation data are continually being supplemented by performance data generated as part of analytical quality control during routine analysis of samples. With each set of analytical samples at least one was fortified with the full quantitative suite (i.e. 136 pesticides and degradation products) at the 0.05 mg kg−1 level. A compilation was made from all the data generated over a period of 12 months, which included data for more than one hundred vegetable and fruit matrices. A limited number of dry matrices (flour, milk powder) were also included in the set. The data were evaluated for one transition for each pesticide, using the API3000 and injection of 2 mg equivalent of matrix (10 μL of a 0.2 g mL−1 extract). Examples of typical extracted ion chromatograms are shown in Fig. 5.Fig. 5

Bottom Line: The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades.The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person.Validation data for 341 pesticides and degradation products are presented.

View Article: PubMed Central - PubMed

Affiliation: Rikilt Institute of Food Safety, Pesticides and Contaminants, P.O. Box 230, 6700 AE, Wageningen, The Netherlands. hans.mol@wur.nl

ABSTRACT
The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary-secondary amine and graphitized carbon black) and large-volume (20 muL) injection. The same extract, before clean-up and after a change of solvent, was also analyzed by liquid chromatography with tandem mass spectrometry (LC-MS-MS). All aspects related to sample preparation were re-assessed with regard to ease and speed of the analysis. The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades. The modifications were made with techniques currently commonly applied in routine laboratories, GC-MS and LC-MS-MS, in mind. The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person. Limits of quantification (LOQs) of 0.01 mg kg(-1) were achieved with both GC-MS (full-scan acquisition, 10 mg matrix equivalent injected) and LC-MS-MS (2 mg injected) for most of the pesticides. Validation data for 341 pesticides and degradation products are presented. A compilation of analytical quality-control data for pesticides routinely analyzed by GC-MS (135 compounds) and LC-MS-MS (136 compounds) in over 100 different matrices, obtained over a period of 15 months, are also presented and discussed. At the 0.05 mg kg(-1) level acceptable recoveries were obtained for 93% (GC-MS) and 92% (LC-MS-MS) of pesticide-matrix combinations.

Show MeSH