Rapid and visual detection of benzothiostrobin residue in strawberry using quantum dot-based lateral flow test strip

A quantitative method was developed for the rapid, visual detection of benzothiostrobin residue in strawberry using the conjugates of CdSe/ZnS (core/shell) quantum dots (QDs) and anti-benzothiostrobin antibody (IgG) based fluorescence lateral flow test strip (FLFTS). The IgG with a binding specificity to the target antigen benzothiostrobin-BSA (a conjugate of benzothiostrobin and bovine serum albumin) was labeled with the QDs to prepare the QD-IgG bioprobes. The primary strategy included the designation of three test lines (T lines), which were sprayed with different concentrations of the antigen. After the spiked samples were added to the sample pad for 15 min at 37 degrees C, the results were visualized with the unaided eye with using ultraviolet (UV) protective goggles under UV lamp with a detection limit of 25 mu g/L. Moreover, the visual detection method together with a gel imager, could be used as a quantitative method. The cut-off values for the T line 1, 2, and 3 were 1200, 600, and 150 mu g/L, respectively. So multi-concentration and visual detection of spiked samples had been achieved. At last, the detection results of the spiked samples by FLFTS were consistent with the results of the UPLC-MS/MS method.