Analysis of pyrrolizidine alkaloids in food – determination of the sum by high-performance thin-layer chromatography and identi-fication by planar solid phase extraction coupled with mass spectrometry

• Applicant: Privatdozentin Dr. Claudia Oellig
• Subject Area: Food Chemistry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 490753836

Two analytical alternatives as screening methods for the analysis of pyrrolizidine alkaloids (PA) in food should be developed. By the easy to perform methods, the determination of the total PA content (sum parameter) in the sample and a fast and cost-effective identification and quantitation of single PA should be possible. In this context, the reduction of the PA should be fundamentally studied and understand. In addition, the liquid-based coupling of planar solid phase extraction with mass spectrometry (pSPE–MS) should be automated for the analysis of PA and completely elaborated for routine application. Furthermore, ion mobility will be investigated within the pSPE–MS approach for the separation of isobaric PA. For the analysis of the total PA by high-performance liquid chromatography with fluorescent detection (HPTLC–FLD), PA will be reduced to the necine base and derivatized to a fluorescent product. This approach will be applicable to PA of the retronecine and heliotridine type and will cover > 90% of the PA. The method for the determination of intact PA by pSPE–MS, which uses the direct online coupling without a chromatographic separation before MS detection, will offer the identification and quantitation of all PA in a single mass spectrum in a very innovative way, since only a few klicks within a database-dependent evaluation approach will be necessary. In the first step, the HPTLC–FLD and the pSPE–MS screening methods will be developed and optimized for representative PA, and subsequently, applied to various tea matrices. In following steps, both screening methods will be adapted to food that is frequently contaminated with PA, such as spices, honey, and cereal-based products. The different food matrices pose a great challenge, because the matrix load is immense compared to the PA content, and the matrices are highly complex. The efficient and cost-effective screening methods will deliver reliable results for the PA content, and thus, provide necessary data on the contamination of food categories with PA. Furthermore, the combination of both methods will represent a very efficient analysis strategy. Both methods will rapidly deliver data on the contamination with PA and, therefore, are very valuable for the estimation of the exposure to PA, which is urgently needed and claimed by the European Union. Additionally, monitoring of recently set maximum levels will be possible. The results of the project will moreover serve the fundamental research on the automated liquid-based pSPE–MS coupling, providing a basis for the coupling strategy to be applicable to various further projects, and offer innovative solutions for actual analytical questions. Thus, the development of several easy to perform and efficient screening methods will be guaranteed. Consequently, the obtained results and knowledge will not only be useful for the PA analysis, but provide fundamental and broad benefit for modern food analysis.

• DFG Programme: Research Grants