Development of Fluorescence Polarization Immunoassay for Imidacloprid in Environmental and Agricultural Samples

Abstract

A fluorescence polarization immunoassay (FPIA) for the determination of imidacloprid (IMI) was developed with advantages of simple operation and short assay time. The haptens of IMI, acetamiprid (ACE), and thiamethoxam (THI) were conjugated with fluorescein isothiocyanate ethylenediamine (EDF) and 4′-Aminomethyl fluorescein (AMF), respectively, to prepare six fluorescence tracers. The conjugation of IMI hapten and EDF (IMI-EDF) was selected to develop the FPIA due to the largest fluorescent polarization value increase in the presence of anti-IMI monoclonal antibody. Under the optimum condition, the limit of detection, 50% inhibition concentration and detection range of the FPIA were 1.7, 4.8, and 1.7–16.3 μg/L, respectively. The cross-reactivities (CRs) with the analogs of IMI were negligible except for imidaclothiz with CR of 79.13%. The average recovery of spiked paddy water, corn and cucumber samples were 82.4–118.5% with the RSDs of 7.0–15.9%, which indicated the FPIA had good accuracy. Thus, the developed FPIA was a potential tool for the rapid and accurate determination of IMI in agricultural and environmental samples.

A Sensitive Fluorescence Polarization Immunoassay for the Rapid Detection of Okadaic Acid in Environmental Waters

“…The selected concentration has to meet two requirements: to ensure a high analytical signal for accurate and reproducible analysis, on the one hand, and to allow for the achievement of the sensitive OA detection, on the other. These requirements are fulfilled at a concentration of antibodies that provide 50–80% binding with antigens [ 28 , 36 ]. Lower concentrations of antibodies cause a significant reduction in the detected signal and worse accuracy of the assay, whereas their higher concentrations limit the sensitive competitive detection of free antigens.…”

“…Ethylenediamine fluoresceinthiocarbamyl (EDF) was synthesized based on the protocol described in [ 28 ]. Ethylenediamine dihydrochloride (200 mg, 1.5 µmol) was dissolved in 50 mL of methanol containing 0.5 mL of triethylamine.…”

“…Currently, many studies have been published on the development of FPIAs using various toxicants, for example, mycotoxins, antibiotics, and pesticides [ 25 , 26 , 27 , 28 ]. The analytical application of this approach for the detection of aquatic toxins is limited to only two papers with the reported FPIAs using hepatotoxins microcystin-LR (MC-LR) and nodularin [ 29 , 30 ].…”

A Sensitive SERS Method for Determination of Pymetrozine in Apple and Cabbage Based on an Easily Prepared Substrate

“…In this study, the standard curve prepared by methanol could not be used for the recovery experiments of the spiked apple and cabbage samples. The main reason can be ascribed to the fact that the pymetrozine extracts from apple and cabbage samples usually contain various impurities, and the sample matrixes could affect the accuracy of SERS detection [21,35,36]. However, the matrix effect can be removed or reduced after a series of purification treatments, and matrix curves were used for apple and cabbage samples analysis.…”

A Robust Homogeneous Fluorescence Polarization Immunoassay for Rapid Determination of Erythromycin in Milk

“…With an increase in the concentration of analytes in the reaction solution, the antibody will be occupied by analytes, and the tracer will be bound to little or no antibody and some tracers will be free, which can lead to the decrease of the FP value. FPIAs have attracted more attention and been reported for the detection of many small molecular compounds, such as veterinary drugs [ 18 , 21 , 22 , 23 ], pesticides [ 24 ], and toxins [ 25 , 26 , 27 ] in food and environmental samples. However, to the best of our knowledge, no report of FPIA for ERY is available.…”