Fluorescence polarization immunoassay for highly efficient detection of clothianidin in agricultural samples

Abstract

A homogeneous fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody was successfully developed and applied in the determination of clothianidin in agricultural samples. Three fluorescein-labeled clothianidin tracers containing different bridge lengths (2-, 4-and 6-carbon bridges) were synthesized and employed to investigate the effect of tracer structures on the FPIA. Under optimal conditions, the fluoresceinthiocarbamyl hexamethylenediamine-labeled clothianidin conjugate (HMDFlabeled clothianidin), which contains a 6-carbon bridge, performed most sensitively in the FPIA for detecting clothianidin, and the detection was achieved by one step in 12 min with a limit of detection of 5.53 ng mL À1 and an IC 50 of 0.0873 mg mL À1 . There were no obvious cross-reactivities of the antibodies with the analogues except for dinotefuran. Recoveries, measured in spiked water, soil, rice, apple, and cabbage samples, ranged from 78.7% to 108.2% with relative standard deviations less than 12.9%. Furthermore, the FPIA for authentic samples showed reliability and high correlations with ELISA of 0.9845 and HPLC of 0.9653. The developed FPIA demonstrated high sensitivity and accuracy, and could be ideally suitable for rapid, simple, and high-throughput screening for clothianidin contamination in agricultural samples.

Heterologous strategy enhancing the sensitivity of the fluorescence polarization immunoassay of clinafloxacin in goat milk

“…It seems that the high CR from ciprofloxacin is usually inevitable in the immunoassay of FQ drugs, but a statutory confirmatory method is usually still needed to exclude the false positive after a screening assay . For a rapid screening purpose, the FPIA with low CR is acceptable considering the speed and convenience of an FPIA …”

Fluorescence polarization immunoassays for carbamazepine – comparison of tracers and formats

“…Thus, the conclusion from previous publications that the longer the spacer, the higher the sensitivity, can be conrmed. 27,[32][33][34] For CBZ-triglycine-AAF, the optimum dynamic range was reached, even by using only half of the antibody amount that had to be used for CBZ-triglycine-EDF. This can be explained by the previously shown high affinity of the antibody towards CBZtriglycine-AAF.…”

“…This assay has been applied to food, diagnostic and environmental analysis to determine small compounds, including mycotoxins, drugs and pesticides. [27][28][29][30][31][32][33][34][35][36][37][38] The principle of FPIA is based on the polarization difference between an unbound and an antibody-bound uorophorelabeled analyte (tracer). The analyte and the tracer compete for the analyte-specic binding sites of the antibody.…”

“…It has been shown that hapten structure and spacer length inuence the performance and especially sensitivity of FPIAs. 27,[32][33][34] Therefore, conjugate design and evaluation is an inherent part of assay optimization.…”

A fluorescence polarization immunoassay for detection of thiacloprid in environmental and agricultural samples

“…Furthermore, due to the one-step detection and ratiometric technique, the FP value is less prone to interference from operational errors and inner-lter effects so that the result is stable and shows good reproducibility. [18][19][20] Besides, the development of portable uorescence polarization detector makes FPIA more potential in pesticide residue detection. [21][22][23] In this work, we prepared an anti-thiacloprid mAb (mAb, C9) with high sensitivity, and labeled thiacloprid hapten with uorescein isothiocyanate (FITC) to develop FPIA for detection of thiacloprid.…”