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. Screening of plant toxins in food, feed and botanicals using full scan high resolution (Orbitrap) mass spectrometry. Food Additives and Contaminants, 2011, 28 (10), pp.1405-1423. <10.1080/19440049.2011

Flow injection combined with tandem mass spectrometry (MS/MS) was investigated for the rapid detection of highly polar pesticides that are not amenable to multi-residue methods because they do not partition into organic solvents and require dedicated chromatographic conditions. The pesticides included in this study were amitrole, chlormequat, cyromazine, daminozide, diquat, ethephon, fosetyl-Al, glufosinate, glyphosate and its metabolite aminomethylphosphonic acid, maleic hydrazide, mepiquat and paraquat. The composition of the flow-injection solvent was optimized to achieve maximum MS/MS sensitivity. Instrumental limits of detection varied between <0.05 and 1 pg. Fruit, vegetable, cereal, milk and kidney samples were extracted with water (1% formic acid in case of paraquat/diquat) and ten times diluted in either methanol/0.1% formic acid, methanol/0.1% ammonia or acetonitrile/0.1% ammonia, depending on the pesticide. The ion suppression observed depended strongly on both the matrix and the pesticide. This could be largely compensated for by matrix-matched calibration, but more accurate quantification was obtained by using isotopically labelled standards (commercially available for most of the pesticides studied). The method detection limits ranged from 0.02 mg/kg for chlormequat and mepiquat to 2 mg/kg for maleic hydrazide and were 0.05-0.2 mg/kg for most other pesticide/matrix combinations. This was sufficiently low to test compliance with EU maximum residue limits for many relevant pesticide/commodity combinations. The method substantially reduces the liquid chromatography-MS/MS capacity demand which for many laboratories is prohibitive for inclusion of these pesticides in their monitoring and surveillance programmes.

In 2017, a Total Diet Study was conducted in the Netherlands in which mycotoxins were analysed in foods and beverages consumed by 1- and 2-year-old children. These mycotoxins were aflatoxins, Alternaria toxins, citrinin, ergot alkaloids, fumonisins, ochratoxin A, patulin, sterigmatocystin, trichothecenes, and zearalenone. Long-term exposure was calculated by combining concentrations in foods and beverages with consumed amounts of these products. Analysed foods and beverages with a concentration below the detection limit that could contain the mycotoxin, were assigned a concentration equal to half this limit value. To assess if the exposure could result in a possible health risk, the high long-term exposure (95th percentile) was compared with a health-based guidance value (HBGV) or a margin of exposure (MOE) was calculated. Exposure to aflatoxins, Alternaria toxins, ochratoxin A and T-2/HT-2 sum may pose a health concern. Foods that contributed most to the exposure of these mycotoxins were bread, biscuits, breakfast cereals, chocolates, dried fruit, follow-on formula and fruit juices.

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Phomopsins (PHO) are mycotoxins produced by the fungus Diaporthe toxica (also referred to as Phomopsis leptostromiformis). Lupin is the most important host crop for this fungus and PHO are suspected as cause of lupinosis, a deadly liver disease, in sheep. Lupin is currently in use to replace genetically modified soy in many food products available on the European market. However, a validated method for analysis of PHO is not available until now. In this work, a dilute-and-shoot LC-MS/MS-based method was developed for the quantitative determination and identification of phomopsin A (PHO-A) in lupin and lupin-containing food. The method involved extraction by a mixture of acetonitrile/water/acetic acid (80/20/1 v/v), dilution of the sample in water, and direct injection of the crude extract after centrifugation. The method was validated at 5 and 25 µg PHO-A kg(-1) product. The average recovery and RSD obtained were 79% and 9%, respectively. The LOQ (the lowest level for which adequate recovery and RSD were demonstrated) was 5 µg PHO-A kg(-1). Identification of PHO-A was based on retention time and two transitions (789 > 226 and 789 > 323). Using the average of solvent standards from the sequence as a reference, retention times were all within ± 0.03 min and ion ratios were within ± 12%, which is compliant with European Union requirements. The LOD (S/N = 3 for the least sensitive transition) was 1 µg PHO-A kg(-1) product. Forty-two samples of lupin and lupin-containing food products were collected in 2011-2012 from grocery stores and internet shops in the Netherlands and analysed. In none of the samples was PHO-A detected.

A straightforward and reliable method was developed for the determination of chlormequat in pears by liquid chromatography/mass spectrometry (LC/MS). Water and methanol were compared as extraction solvents. Because no significant differences in extraction efficiency or repeatability were found, water was chosen as the extraction solvent. The extracts were analyzed without cleanup by either an ion-trap liquid chromatograph/mass spectrometer in the single MS mode or a triple-quadrupole instrument in the MS/MS mode, using electrospray ionization. Both instruments were equally suitable for quantitation and confirmation of identity. Recoveries were 76–103%, and reproducibility was ≤12%. The lowest detection limit (0.007 mg/kg) was obtained with the triple-quadrupole instrument in the MS/MS mode.