Study on Magnetic Solid Phase Extraction-immunochromatography for Trace Methamphetamine in Sewage

This study established an analytical method suitable for the rapid on-site detection of trace methamphetamine (MET) in sewage by integrating magnetic solid phase extraction (MSPE) with immunochromatographic technology. Using magnetic nanospheres conjugated with monoclonal antibodies against methamphetamine (MET) as an immunomagnetic probe, solid-phase extraction was employed to enrich and extract methamphetamine drugs in sewage. Subsequently, the extracted methamphetamine was then quantified using colloidal gold immunochromatographic test strips. The quantitative analysis of methamphetamine was carried out by optimizing various parameters such as the amount of labeled antibody, the pH of desorption solution, the desorption time, the water sample volume, and the water sample pH. The experimental results showed that the regression equation of the standard curve of the prepared test strip was 0.9996, and the detection limit was 0.13 ng/mL. The combination of immunomagnetic probes and colloidal gold immunochromatography enabled the detection of trace methamphetamine drugs in sewage samples within 30 minutes. The method utilized a sewage sample volume of 50 mL, achieving a concentration factor of 50 times, with a quantitative detection limit of 8 ng/L. This combined method is simple to operate, time-efficient, and has low dependence on specialized equipment. Additionally, it does not require the use of organic solvents. It is suitable for the rapid on-site detection of trace amounts of methamphetamine drugs in sewage. Additionally, it can serve as an auxiliary tool for laboratory detection of sewage samples and be applied to the monitoring of urban sewage toxicity, thus playing an important role in relevant fields.