Immediate, sensitive and specific time-resolved fluorescent immunoassay strips based on immune competition for the detection of procymidone in vegetables

As an organochlorine pesticide, procymidone has become an increasing serious problem in vegetables in recent years. In order to solve a series of problems such as low sensitivity of the immunological methods, a time-resolved fluorescent immunoassay strip (TRFIAS) was developed with low limit of detection (LOD). Based on the principle of antigen-antibody immune competition, TRFIAS could detect procymidone in vegetables. After the targets being added, the samples were incubated at 37°C for 10 min. TRFIAS was observed under a UV lamp of 365 nm. The results were processed by ImageJ software to complete the qualitative and quantitative analysis of TRFIAS. Under the optimal working conditions, a linear range of TRFIAS was 5–250 ng/mL with a LOD of 0.33 ng/mL and a visual limit of detection (VDL) of 50 ng/mL. And the TRFIAS had good specificity, precision and accuracy. Comparing the results of TRFIAS with those of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the two assays were in good agreement. Therefore, TRFIAS has the advantages of high sensitivity, high specificity, simple operation and relatively short assay time. Meanwhile, it shows absolutely great advantages in both quantitative and qualitative analysis.