A double-label time-resolved fluorescent strip for rapidly quantitative detection of carbofuran residues in agro-products

•A time-resolved fluorescent strip was developed based on double-label immunoprobes.•The quantitative TRFICA's LODs may reach 0.04 mg L−1 in apple extraction solution.•Strip assay sensitivity is increased or similar to the previous GNP strip assays.•The spiked recoveries of carbofuran in the agro-products were 81-103%.•The TRFICA's results were in good agreement with a standard HPLC method.

A rapid and quantitative time-resolved fluorescent immunochromatographic assay (TRFICA) for detecting carbofuran residues in agro-products was reported in this paper. This assay was developed based on double-label immunoprobes, one of which was a carbofuran-specific antibody coupled with europium microbeads for the test (T) line signal while the other was mouse IgG coupled with europium microbeads for the control (C) line signal. Quantitative relationships between carbofuran concentrations and T/C ratios were established to determine the analyte concentration. To increase assay accuracy, four standard curves were established for the agro-products (green bean, cabbage, apple, and pear). The limits of detection (LODs) ranged from 0.04 to 0.76 mg L−1. The spiked recoveries of carbofuran in the agro-products were in the range of 81-103%, which was in good agreement with a standard HPLC method. Therefore, we provided a new and reliable method for determination of N-methylcarbamate pesticide carbofuran residues in agro-products including vegetables and fruits.