Herrmann, Susan Strange

Poulsen, Mette Erecius

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Nov 09, 2017Clean-up experiments of oat extracts for pesticide residues analysis by PSA, C18, Z-sep or EMR-lipid, individually and combinationsHerrmann, Susan Strange; Poulsen, Mette EreciusPublication date:2016Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Herrmann, S. S., & Poulsen, M. E. (2016). Clean-up experiments of oat extracts for pesticide residues analysisby PSA, C18, Z-sep or EMR-lipid, individually and combinations. Poster session presented at 11th EuropeanPesticide Residue Workshop, Limassol, Cyprus.Clean-up experiments of oat extracts for pesticide residues analysis by PSA, C18, Z-sep or EMR-lipid, individually and combinations Herrmann, Susan Strange and Poulsen, Mette Erecius National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark. e-mail : sher@food.dtu.dk        Introduction Conclusion The level of co-extracted matrix in QuEChERS cereal extracts (EN 15662) is generally high but the highest levels are found in oat extracts due to the high fat content. Especially for oat flour stored at room temperature the matrix can result in poor method performance.  With the present study the EURL-CF wanted to elucidate whether an optimised clean-up procedure, employing more than one sorbent, could be suggested for oat  flour stored 4 weeks at room temperature. Besides PSA were Z-sep (zirconium based sorbent), EMR-lipid (enhanced matrix removal-lipid) and C18 found relevant to include in the study.  All four sorbents reduced the amount of co-extracted matrix in the oat extracts, demonstrated by reduction of the matrix residue (mg/ml extract)(Figure 1) and the intensity of the major matrix peaks in the GCMS chromatogram (Figure 2). Though, PSA had the most pronounced reducing effect on both the residual matrix as well as the matrix peaks. Ultracentrifugation had virtually no effect and the amount of co-extract.  From the results of the factorial experiment we found that PSA, Z-sep as well as EMR-lipid increased the number of analytes for which acceptable recoveries (60-130%) were obtained (Table 1 and Figure 3.1, 3.3. and 3.4). Though PSA has the most pronounced effect. C18 on the other hand reduced the number of analytes with acceptable recoveries (Figure 3.2) also if used in combination with other sorbents (Figure 3.5, 3.7 and 3.9).  The study showed that a combination of more than one sorbent provide better analytical results when analysing a problematic matrix as oat flour. A combination of PSA, Z-sep and EMR-lipid or Z-sep and EMR-lipid provided the highest number of analytes with recoveries between 60-130%.  Study design Extracts, un-cleaned or cleaned by dSPE with PSA, C18, Z-sep, EMR-lipid or ultracentrifugation, were evaporated to dryness and the amount of matrix determined (mg/ml extract)(Figure 1). GCMS chromatograms of these extract were obtained (Figure 2, ultracentrifugation not shown).  A four factor 2-level factorial experiment (full resolution) was setup to study the effect of the four sorbents on the matrix level and analyte recoveries of 101 pesticides (spike level 0.02 mg/kg). Test sample 1-16 (double determination) were extracted with the QuEChERS method and clean-up in accordance with the design presented in the Table 1. Analyses of the final extracts were performed on GC-MS/MS.  Table 1: Design of 2-level factorial experiment (full resolution).  Figure 1: The residue amount of co-extracted matrix (mg/ml extract) measured after evaporation to dryness of oat extracts. Mean of double determinations except for EMR-lipid which was a single determination (market with an asterisk). Sample PSA  ( extract) C18  ( extract) Z-sep  ( extract) EMR Analytes w. recov. 60-130% 1 0 0 0 0 41 2 150  0 150  0 68 3 150  150  150  EMR-lipid 42 4 0 150  0 0 39 5 0 150  0 EMR-lipid 53 6 150  0 0 EMR-lipid 65 7 0 0 150  EMR-lipid 78 8 0 0 150 0 37 9 0 150  150  0 39 10 150  0 0 0 42 11 0 150  150  EMR-lipid 51 12 150  150  150  0 75 13 150  0 150  EMR-lipid 84 14 150  150  0 0 71 15 0 0 0 EMR-lipid 48 16 150  150  0 EMR-lipid 42 Figure 3: Main effects and interaction plots (Minitab 17) based on no. of analytes (101 in total) for which recoveries between 60-130% was obtained following the 16 different clean-up procedures (an asterisk indicate that the effect is significant P<0.05). Zr: Z-sep. Results Un-cleaned PSA  C18 Z-sep  EMR-lipid Figure 2: GCMS chromatogram of oat extracts after no cleanup or dSPE cleanup with PSA, C18, Z-sep (200 mg/ml) or EMR-lipid. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10  EURL-CF: EU Reference Laboratory for pesticide Residues in Cereals and Feeding stuff, DTU National Food Institute, Moerkhoej Bygade 19, DK-2860 Soeborg, Denmark   e-mail :  eurl-cf@foood.dtu.dk,  www.eurl-pesticides.eu   

Clean-up experiments of oat extracts for pesticide residues analysis by PSA, C18, Z-sep or EMR-lipid, individually and combinations

http://orbit.dtu.dk/ws/files/124123519/2016_Poster_EPRW_Cleanup_final.pdf

Clean-up experiments of oat extracts for pesticide residues analysis by PSA, C18, Z-sep or EMR-lipid, individually and combinations

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology