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Fumonisin Bs (FBs) are the most common toxic and carcinogenic substances found among naturally occurring contaminants of cereals. A group-specific monoclonal antibody (mAb) 2H7 was prepared that equably recognized fumonisins B 1 (FB 1), B 2 (FB 2), and B 3 (FB 3) with a half-maximal inhibitory concentration (IC 50) value for the three forms of 1.52, 2.93, and 3.85 ng/ml, respectively. On this basis, a fluorescent microsphere-based immunochromatographic strip (FM-ICS) was established for the rapid qualitative and quantitative detection of total FBs (FB 1 , FB 2 , and FB 3) in corn, wheat, and rice. A recovery test showed that the recovery of FM-ICS was 92.8–108.3% with coefficients of variation of 1.2–7.9%. This method has the same reliability as seen with liquid chromatography-tandem mass spectrometry. And the accuracy was further confirmed by certified reference materials. Therefore, it can be used for the detection of FBs in cereal samples. • A group-specific monoclonal antibody 2H7 was prepared that equably recognized fumonisins B 1 , B 2 , and B 3. • FM-ICS was established for the rapid qualitative and quantitative detection of total FBs in corn, wheat, and rice. • FBs certified reference materials confirmed the feasibility of FM-ICS. [ABSTRACT FROM AUTHOR]

Abstract: A competitive time-resolved fluoroimmunoassay (TR–FIA) was developed for the determination of diethylstilbestrol (DES) residues in chicken liver. Prior to analysis, the residues were extracted from chicken liver with acetonitrile. The assay could be used in a quantitative or qualitative mode. The limit of detection (LOD) was determined to be 0.05ngg−1, and the limit of quantification (LOQ) was less than 0.18ngg−1. The intraassay variations were less than 10%, and the interassay variations were from 9.8 to 12.7%. The mean recoveries established at six concentration levels varied from 84.3 to 109.6%, and the coefficients of variation were from 8.3 to 12.4%. The results obtained by the TR–FIA and enzyme-linked immunosorbent assay (ELISA) showed a good correlation. The established TR–FIA was validated for the determination of incurred chicken liver and was confirmed by liquid chromatography and tandem mass spectrometry (LC–MS/MS). This proposed technique could be applied to routine residue analysis. [Copyright &y& Elsevier]

Etoxazole, a novel organofluorine pesticide, has been widely used against various mites in fruits and vegetables. In this study, we designed an etoxazole-hapten and produced a highly sensitive monoclonal antibody (mAb) against etoxazole with a half-maximal inhibitory concentration of 4.04 ng/mL. Based on the mAb, we developed an immunochromatographic assay (ICA) for the detection of etoxazole in orange and grape samples. In the qualitative detection, the visible limit of detection (vLOD) and cut-off value were 10 and 100 ng/g (fresh weight), respectively. In the quantitative detection, the LOD value was 2.03 ng/g (fresh weight) in orange and 2.52 ng/g (fresh weight) in grape samples. The recovery rates ranged from 94.7 ± 4.0% to 103.3 ± 3.8%, with CVs of 3.7–4.2% and 96.4 ± 3.4% to 106.1 ± 5.5%, with CVs of 3.5–5.2% for etoxazole in grape and orange samples, respectively. The ICA results were similar to those of LC-MS/MS. Therefore, our developed ICA is a rapid, sensitive, and simple tool for screening etoxazole residues in fruits and vegetables. • A novel hapten of etoxazole was synthesized. • A half-maximal inhibitory concentration is 4.04 ng/mL. • The cLODs of the ICA were 2.03 and 2.52 ng/g in orange and grape. • Good correlations of the results obtained by ICA, ELISA and LC-MS/MS. [ABSTRACT FROM AUTHOR]

Abstract: The fluorescence-encoded microspheres were prepared by the simple and controllable microfluidic device for the first time. The polycaprolactone (PCL) microspheres were encoded with different quantum dots (QDs) at various ratios, and the fluorescence was decoded successfully. The designed fluorescence encoding method was easily manipulated, and generated the uniform microspheres with different size. This research demonstrated a very facile and promising technique for fluorescence encoding over traditional methods. [ABSTRACT FROM AUTHOR]