Search

In this paper, we report the development of a sensitive and specific monoclonal antibody-based immunodiagnostic method for the detection of iso-tenuazonic acid (ITeA), an Alternaria mycotoxin, in food samples. The ITeA was derivatized with hydrazine hydrate to produce the antigen (E)-3-(1-hydrazonoethyl)-4-hydroxy-5-isobutyl-1H-pyrrol-2(5H)-one (ITeAH) which was further reacted with glyoxalic acid to generate the hapten (E)-2-((Z)-(1-(4-hydroxy-5-isobutyl-2-oxo-2,5-dihydro-1H-pyrrol-3-yl)ethylidene) (ITeAHGA) which was used as an immunogen after conjugation to bovine serum albumin (BSA). A highly specific monoclonal antibody selectively binding to ITeAH was generated via the hybridoma technique and subsequently used to construct a heterologous indirect competitive enzyme-linked immunosorbent assay (icELISA) using ITeAH as the competitive antigen for the detection of ITeA with a limit of detection (LOD) of 0.5 ng/mL. Under the optimum conditions, the developed icELISA is highly sensitive (IC = 7.8 ng/mL) with recovery rates ranged from 82.3 to 109.8% for spiked food samples. The comparative analysis of results revealed a good correlation between the icELISA and the standard HPLC-MS/MS method, confirming the suitability of the developed icELISA for screening and detection of mycotoxin ITeA in food samples. [ABSTRACT FROM AUTHOR]

A simple and rapid method for determination of carbofuran was developed using the fluorescence polarisation immunoassay (FPIA). Three tracers with different lengths of bridge (0-, 2- and 6-carbon bridge) between the hapten molecule 4-[[(2,3-dihydro-2,2-dimethyl-7-benzofuranyloxy)carbonyl]-amino]-butanoic acid (BFNB) and 5-aminofluorescein (AF), fluoresceinthiocarbamyl ethylenediamine (EDF), fluoresceinthiocarbamyl hexylenediamine (HDF), were synthesised and their binding response with anti-carbofuran-specific antibody were evaluated. The physicochemical parameters were optimised for the FPIA. The AF-labelled BFNB conjugate (BFNB-AF) was found to be the optimal tracer for FPIA of carbofuran. The detection limit of carbofuran, IC50value and the working range were 2.3, 48.8 and 7.4−202.2 µg/L, respectively; and the reaction time was only 10 min. The average recovery from spiked water and vegetable samples was 86.9−95.4% and the mean coefficient of variation was 6.2% for inter-assay and 8.7% for intra-assay, which showed good reproducibility for FPIA. Thus, the developed FPIA method exhibited the potential for the rapid and accurate determination of carbofuran in agricultural and environmental samples. [ABSTRACT FROM AUTHOR]

In this work, a monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay (icELISA) was established to detect tylosin and tilmicosin in milk and water samples. A sensitive and specific monoclonal antibody was prepared by rational designed hapten, which was achieved by directly oxidizing the aldehyde group on the side chain of tylosin to the carboxyl group. Under the optimized conditions, the linear range of icELISA for tylosin and tilmicosin were 1.3 to 17.7 ng/mL and 2.0 to 47.4 ng/mL, with half-maximal inhibition concentration (IC50) values of 4.7 and 9.6 ng/mL, respectively. The cross-reactivity with other analogues of icELISA was less than 0.1%. The average recoveries of icELISA for tylosin and tilmicosin ranged from 76.4% to 109.5% in milk and water samples. Besides, the detection results of icELISA showed good correlations with HPLC-MS/MS. The proposed icELISA was satisfied for rapid and specific screening of tylosin and tilmicosin residues in milk and water samples. [ABSTRACT FROM AUTHOR]

Abstract: A simple, rapid and high-throughput fluorescent polarization immunoassay (FPIA) for simultaneous determination of organophosphorus pesticides (OPs) using a broad-specificity monoclonal antibody was developed. The effects of tracer structure, tracer concentration, antibody dilution, methanol content and matrix effect on FPIA performance were studied. The FPIA can detect 5 OPs simultaneously with a limit of detection below 10ngmL−1. The time required for the equilibrium of antibody–antigen interaction was less than 10min. The recovery from spiked vegetable and environmental samples ranged from 71.3% to 126.8%, with the coefficient of variations ranging from 3.5% to 14.5%. The developed FPIA was applied to samples, followed by confirmation with high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) analysis. The developed FPIA demonstrated good accuracy and reproducibility, and is suitable for rapid and high-throughput screening for OP contamination with high-efficiency and low cost. [Copyright &y& Elsevier]