Method development for determination of multi-mycotoxin in vegetable oil using QuEChERS technique and liquid chromatography tandem mass spectrometry
In recent years, vegetable oils were reported to be contaminated by mycotoxins. At the same time, demand for vegetable oils has been increasing due to its health benefit and also for its direct use or as ingredients in food. The objectives of this study were to develop and validate the QuEChERS (Qui...
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| Format: | Thesis |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/65744/1/FSTM%202015%2032IR.pdf |
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| Summary: | In recent years, vegetable oils were reported to be contaminated by mycotoxins. At the same time, demand for vegetable oils has been increasing due to its health benefit and also for its direct use or as ingredients in food. The objectives of this study were to develop and validate the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction and clean-up procedures for mycotoxins in vegetable oil by liquid chromatography tandem mass spectrometry (LC-MS/MS) and to verify the established method in vegetable oils in Malaysian market. In this study, a new, fast, cost efficient, sensitive and accurate assay method was developed, optimized and validated for the determination of aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEA) and deoxynivalenol (DON) in vegetable oil by a modified QuEChERS approach, which was conventionally developed for pesticides analysis. A quick procedure of mycotoxins extraction and clean-up was achieved in two steps. Firstly, target analytes were extracted into the optimized solvent acetonitrile and followed by dispersive solid phase extraction (dSPE) clean up with the optimized sorbents to remove the co-extracts. Three types of d-SPE sorbents; C18, primary secondary amine (PSA) and graphitized carbon black (GCB) and four combination ratios of two selected d-SPEs were evaluated to achieve an optimum and acceptable result. The maximum co-extracts were removed when d-SPE C18 and GCB were used at ratio 3:1 with MgSO4 anhydrous followed by LC-MS/MS analysis, using an electro spray-ionization interface (ESI). Methanol as an organic phase and formic acid (0.1%) with 5 mM ammonium acetate as a polar phase, with total run of 16 minutes and flow rate 300 µLmin-1 were applied. The validation study indicated the seven mycotoxins could be detected in the concentration range of 0.01 ngg-1 to650.17ngg-1 with correlation coefficient > 0.98. The limit of quantitation (LOQ) ranges from 0.04 ngg-1 to 2000 ngg-1. The recoveries were in the range of 87.9% to 106.6%. The repeatability and reproducibility of the analysis were within the acceptable level (0.5 – 1.3) for precision using HORRAT ratio. Significant matrix effect was compensated using the matrix matched calibration curves. After validation, the method was successfully applied to 25 vegetable oil samples including corn oil, palm oil and sunflower oil. ZEA, AFG2, AFG1 and AFB1 were among the detected mycotoxins. A new fast, cost efficient, sensitive and accurate assay method was successfully developed, validated and applied for the determination of seven mycotoxins in vegetable oils. |
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