Design and development of heterologous competitive immunoassays for the determination of boscalid residues

Abstract

Boscalid is a modern agrochemical belonging to the so-called chemical class of succinate dehydrogenase inhibitor fungicides. With the aim of developing rapid analytical screening methods for this relevant compound, we herein report the synthesis of new boscalid mimics and the study of their suitability for the production of polyclonal antibodies. Aliphatic spacer arms equivalent in length and composition were tethered at two different aromatic rings of the target molecular structure. These haptens, besides being used for immunization, were employed in the development of heterologous competitive enzyme-linked immunosorbent assays (cELISAs) in order to improve assay detectability. Direct and indirect immunoassays were tailored and applied to the determination of samples with incurred boscalid residues. The assays were characterized in terms of sensitivity, specificity, trueness, and precision. Limit of quantification was established at 5 μg kg(-1), coefficients of variation were lower than 20%, and recoveries from spiked samples ranged from 90 to 137%. Finally, ELISA performance was evaluated by Deming regression analysis with tomato and cucumber samples, selecting ultra-performance liquid chromatography-mass spectrometry as the reference method. The results showed that the proposed cELISAs are useful for the routine determination of boscalid fungicides in foods with high-sample throughput and affordable cost.

Fluxapyroxad Haptens and Antibodies for Highly Sensitive Immunoanalysis of Food Samples

“…Therefore, in this particular case, the sensitivity of the direct assay was slightly better than that of the indirect assay, probably due to the antibody characteristics. Generally, when polyclonal antibodies are used, heterologous conjugates enhance assay sensitivity of both cELISA formats, and similar sensitivities are usually attained with either format, as previously reported for other small chemical compounds [26][27][28]. Finally, the theoretical dynamic working range was established between 0.09 nM (0.034 µg/L) and 4.30 nM (1.640 µg/L) for the direct assay, and between 0.30 nM (0.114 µg/L) and 17.89 nM (6.820 µg/L) for the indirect format.…”

Dissipation behaviour and dietary risk assessment of boscalid, triflumizole and its metabolite (FM‐6‐1) in open‐field cucumber based on QuEChERS using HPLC–MS/MS technique

“…Boscalid (PubChem CID: 213013), a wide‐spectrum aniline fungicide, is a compound with the function of dehydrogenase inhibition . This chemical is broadly employed to fight against fungal diseases by inhibiting fungi mitochondrial respiration through deactivating complex II (succinate ubiquinone reductase or succinate dehydrogenase) in the mitochondrial electron transport chain …”

“…1 This chemical is broadly employed to fight against fungal diseases by inhibiting fungi mitochondrial respiration through deactivating complex II (succinate ubiquinone reductase or succinate dehydrogenase) in the mitochondrial electron transport chain. 2 Triflumizole (PubChem CID: 91699), (E)-4-chloro-, , -trifluoro-N-(1-imidazol-1-yl-2-propoxyethylidene)-o-toluidine (IUPAC), as one of the wide-spectrum fungicides of imidazole, could inhibit ergosterol synthesis and cumulate sterol intermediates by interfering with the sterol biosynthesis pathway. 3 FM-6-1 (PubChem CID: 13783710) has been proved to be the main metabolite of triflumizole in cucumber, whose toxicity mechanism is largely unknown.…”

“…In this study, we aimed: (1) to explore and validate a sensitive and effective method for multidetermination of boscalid, triflumizole and FM-6-1 in soil and cucumber based on the QuEChERS method with the LC-MS/MS technique; (2) to investigate the degradation behaviour and residue distribution of two fungicides in cucumber and soil in three regions of China under open-field conditions; and (3) to evaluate the dietary risk of pre-mixed boscalid and triflumizole SE in cucumber, with the basic information and the distributions of terminal residues.…”

Rational design of a fluopyram hapten and preparation of bioconjugates and antibodies for immunoanalysis

“…S1 †) of the prepared biomolecules are included in the ESI. † Two rabbits were immunized with 300 mg of BSA bioconjugate and antisera were obtained following established procedures 16 in compliance with the laws and guidelines of the Spanish Ministry of Agriculture, Food, and Environment, and approved by the Ethics Committee of the University of Valencia (permit number: A1329731961154). Blood samples were taken from the ear vein aer the third injection, and total sera were collected 10 days aer the nal boost.…”