Development of a novel non-targeted analytical method on evaluating the thermal stability of pesticides, enabling the identification of degradation products

Abstract

Aim: The present work aims to propose an alternative analytical protocol for assessing the thermal stability of plant protection products between 90°C and 240°C. In that view, this work seeks to identify any degradation products that may be overlooked during regulatory hydrolysis studies. Thus, we evaluate if a new regulatory approach is necessary and how this could be done by academic research. This requires working under similar conditions. Methods: A comprehensive analytical workflow was designed and implemented for ten active substances to study and investigate their overall degradation behaviour and volatilisation. The results were then compared with those reported in the regulatory studies. Results: The ratio of detected degradation products to active substances ranged from 0.5% to 50%. Volatilization products were identified for all compounds analyzed using TGA-GC-MS. This confirmed the pattern of degradation followed by volatilisation, except for tetraconazole, which volatilises before degradation. Some of the detected compounds were not reported at all in regulatory studies, or were detected at higher concentrations, such as IN-EQW78 and 500M07. Conclusions: This study confirmed the feasibility of conducting thermodegradation studies without relying on radiolabelled substances. It also identified two overlooked products and emphasised the importance of conducting studies exceeding 120°C.

Keywords

Degradation studies / volatilisation studies / active substance / suspect screening analysis / non-target analysis

References

[1] Damalas CA. Understanding benefits and risks of pesticide use. Sci Res Essays. 2009; 4: 945-9.

[2] European Parliament and Council. Regulation (EC) No 1107/2009 of the European Parliament and of the Council of 21 October 2009 concerning the placing of plant protection products on the market and repealing Council Directives 79/117/EEC and 91/414/EEC. Official Journal of the European Union; 2009.

[3] EFSA Panel on Plant Protection Products and their Residues (PPR). Guidance on the establishment of the residue definition for dietary risk assessment. EFSA. 2016; 14: e04549.

[4] Yigit N, Velioglu YS. Effects of processing and storage on pesticide residues in foods. Crit Rev Food Sci Nutr. 2020; 60: 3622—41.

[5] Test No. 507: Nature of the Pesticide Residues in Processed Commodities — High Temperature Hydrolysis[Internet]. Organisation for Economic Co—operation and Development; [cited 2007 Oct 15]. Available from: https://www.oecd.org/en/publications/2007/10/test—no—507—nature—of—the—pesticide—residues—in—processed—commodities—high—temperature—hydrolysis_g1gh87c0/support—materials.html

[6] Dubocq F, L’Yvonnet P, Chatzidimitriou E, Mahouche—Chergui S, Sarda X, Vial G, et al. Towards comprehensive identification of pesticide degradation products following thermal processing below and above 120°C: A review. Food Chem. 2023; 402: 134267.

[7] Martin D, Lobo F, Lavison—Bompard G, Guérin T, Parinet J. Effect of home cooking processes on chlordecone content in beef and investigation of its by—products and metabolites by HPLC—HRMS/MS. Environ Int. 2020; 144: 106077.

[8] Göckener B, Kotthoff M, Kling HW, Bücking M. Processing Induced Degradation Routes of Prochloraz in Rapeseed Oil. J Agric Food Chem. 2019; 67: 12293—302.

[9] Devriendt—Renault Y, Massat F, Guérin T, Parinet J. Impact of classical home cooking processes on chlordecone and chlordecol concentrations in animal products originated from French West Indies. Food Control. 2023; 152: 109871.

[10] L’Yvonnet P, Vial G, Sarda X, Duboisset A, Carbonnier B, Parinet J, et al. Thermal degradation of pesticide active substances: Prioritisation list. Food Chemistry Advances. 2023; 2: 100327.

[11] von Eyken A, Furlong D, Arooni S, Butterworth F, Roy JF, Zweigenbaum J, et al. Direct injection high performance liquid chromatography coupled to data independent acquisition mass spectrometry for the screening of antibiotics in honey. J Food Drug Anal. 2019; 27: 679-91.

[12] Wang M, Carver JJ, Phelan VV, Sanchez LM, Garg N, Peng Y, et al. Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking. Nat Biotechnol. 2016; 34: 828—37.

[13] Schymanski EL, Jeon J, Gulde R, Fenner K, Ruff M, Singer HP, et al. Identifying Small Molecules via High Resolution Mass Spectrometry: Communicating Confidence. Environ Sci Technol. 2014; 48: 2097—8.

[14] Ramaswamy HS, Koutchma T, Tajchakavit S. Enhanced thermal effects under microwave heating conditions. In: Engineering and Food for the 21st Century. London: CRC Press; 2002.

[15] The European Food Safety Authority. Public consultation on the active substance hexythiazox. Parma: EFSA; 2006.

[16] The European Food Safety Authority. Public consultation on the active substance chlorantraniliprole. Parma: EFSA; 2012.

[17] The European Food Safety Authority. Public consultation on the active substance pyraclostrobin. Parma: EFSA; 2018.

[18] Liigand J, Wang T, Kellogg J, Smedsgaard J, Cech N, Kruve A. Quantification for non—targeted LC/MS screening without standard substances. Sci Rep. 2020; 10: 5808.