engleski

Microfiltration affects mycotoxin recovery

Frequent multi-mycotoxin occurrences in various foods, alongside adverse health effects and legislative requirements, demand constant and continuous monitoring to properly assess the level of mycotoxin contamination. Sensitive and unambiguous quantification of multiple analytes requires state-of-the-art analytics, such as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). To protect the instrument from small particles while reducing the matrix effect, many LC-MS/MS methods employ membrane filtration during sample preparation. However, when membrane filtration is used, possible adsorptive effects at membrane filters should also be considered, as they could prevent the accurate determination of mycotoxin (co-)occurrence and the real risk assessment for public health. In this study, five different material types of syringe filters, i.e. nylon (NY), polytetrafluoroethylene (PTFE), polyethersulfone (PES), mixed cellulose ester (MCE), and cellulose acetate (CA), were used to assess the impact of microfiltration on mycotoxin recovery. All 11 of the legislatively regulated mycotoxins were selected for the investigation, including aflatoxins B1, B2, G1 and G2, deoxynivalenol, fumonisins B1 and B2, zearalenone, T-2 and HT-2 toxins, and ochratoxin A. The combined mycotoxin standard solution was prepared in concentrations 0.25-50 ng/mL using acetonitrile/water/formic acid (49.5/49.5/1, v/v/v). This multi-mycotoxin solution was filtrated using different syringe filters where the first three filtrate drops and the following filtrate were collected separately into vials and injected in triplicates into a LC-MS/MS system and analysed using a validated instrumental method. The recovery for each mycotoxin was calculated comparing the average area of the filtered and unfiltered standard solution and expressed in percentage. The results revealed that PTFE filters have the least impact on mycotoxin loss during filtration, while commonly used NY filters could affect the recoveries of certain mycotoxins if not properly used. A decrease in the recoveries of almost all mycotoxins was observed in the first three nylon filter drops, especially for aflatoxin B1 and zearalenone (up to 30 %), while the following filtrate contained a satisfying amount of all of the tested mycotoxins, when compared to the unfiltered solution. Therefore, for accurate mycotoxin determination, the first few filtrate drops should be discarded, as they saturate membrane filter materials, once again pointing to the importance of a proper method development procedure.

liquid chromatography-tandem mass spectrometry ; multi-mycotoxins ; public health ; risk assessment ; sample preparation

nije evidentirano