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无锡微色谱生物科技有限公司
MicroSep Biotechnology Co. LTD.
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JA0049 PESTICIDES AND ADULTERANTS IN FOOD PRODUCTS: CHALLENGES AND SOLUTIONS FOR SAMPLE PREPARATION FOR GAS CHROMATOGRAPHY/MASS SPECTROMETRY
来源: | 作者:PESTICIDES AND ADULTERANTS IN FOOD PRODUCTS: CHALLENGES AND SOLUTIONS FOR SAMPLE PREPARATION FOR GAS CHROMATOGRAPHY/MASS SPECTROMETRY | 发布时间: 87天前 | 198 次浏览 | 分享到:
Routine and comprehensive testing of food products is essential to ensure that toxic pesticides or other adulterants are below tolerance levels. This dissertation involves development and validation of simple, rapid, cost-effective, and reliable methods for extraction of adulterants from foods prior to gas chromatography-mass spectrometry (GC-MS) analysis. Sample cleanup is necessary because food contains fatty acids, sugars, proteins, and other endogenous compounds that would otherwise interfere with analysis. Disposable pipette extraction (DPX) involves pulling an aqueous sample into a pipette tip packed with sorbent material and separation of the target compounds from the interferences. Dynamic mixing of DPX sorbent with solutions provides rapid equilibration, partitioning and enhanced contact between analytes and solid phase sorbent. Food adulterants targeted include multiresidue pesticides, fungicides, and two specific contaminants, melamine and cyanuric acid. A reversed phase sorbent (DPX-RP) and mixed-polarity sorbent (DPX-Q) similar to a commercially available product were used for the extraction of organochlorine and organophosphate pesticides, and fungicides, in fruits and vegetables. The hydrophobic nature of the DPX-RP sorbent provides efficient extraction of these slightly polar and non-polar compounds. Although extracts after DPX-Q cleanup contain some interferences, high recoveries were achieved for most pesticides, including very polar pesticides. Suitability for routine analysis was validated by a collaborative study at South Carolina Department of Agriculture with GC/MS and GC/electron capture detection. iv The extraction of organochlorine and organophosphate pesticides in food samples containing 10 to 50% of fat, using weak anion exchange sorbent (DPX- WAX), is also described. The high capacity nature of this sorbent provides easy and quick removal of fatty acids interferences from high fat content samples prior to pesticide analysis. Recent cases of melamine adulteration affected the health of over 50,000 children and caused six deaths in children in China as a result of kidney failure. As with any food adulterants, adequate public and regulatory actions are dependent on the quality of analyses. Cation (DPX-CX) and DPX-WAX cleanup followed by GC-MS is shown to provide the required sensitivity, specificity, and accuracy to meet safety thresholds set by the U.S. Food and Drug Administration for melamine and its analog, cyanuric acid.

Organochlorine, organophosphate pesticides and fungicides in fruits and vegetables were rapidly analyzed using disposable pipette extraction (DPX) followed by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM). The DPX methods involved in this study was DPX-RP (reversed phase). DPX’s rapid intrinsic mixing capability results in fast extractions with analytes being concentrated, and eliminated the need for solvent evaporation. Extraction of pesticides from fruits and vegetable using this technique achieved a sample preparation throughput on the order of a few minutes per sample. Matrix-matched calibrations were performed, and limits of detection (LODs) were determined to be lower than 0.1 ppm. Coefficients of determination (r2) were greater than 0.995 for most studied pesticides. The developed method exhibited an overall recovery of 72-116% for non-polar and slightly polar pesticides, with relative standard deviations of the recoveries below 10%, which indicates a good accuracy and precision of the proposed method


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