An ultrasensitive monoclonal antibody-based lateral flow immunoassay for the rapid detection of xylazine in milk

In this study, a novel hapten was designed and successfully synthesized to prepared the artificial immunogen against xylazine (XYL), then the monoclonal antibody 1H2-2C6 was obtained and applied to a lateral flow immunoassay (LFI) strip for rapid detection of XYL in milk. The visual detection limit (cutoff value) of the LFI strip was 5 ng/mL, the linear regression formula was Y = -0.521lg(X) + 0.382 (R2 = 0.995, n = 6), the linear detection range was 0.16-2.23 ng/mL and the detection limit (LOD) was 0.1 ng/mL. The recovery rates were in the range from 88.95% to 91.45%, the highest coefficient of variation was 8.89% (n = 3). The LFI strip was also validated by LC-MS/MS, as revealed, there were no significance differences between the two methods (the confidence interval was 95%). In brief, the LFI strip provides a reliable, sensitive and portable testing tool for screening of XYL on-site.