Visual lambda-cyhalothrin detection using yellow carbon dots molecularly imprinted polyvinylidene fluoride fluorescent membrane

Due to its common use as an insecticide during agricultural production, residual lambda-cyhalothrin (LC) in food and the environment presents a significant human health risk. Developing an accurate LC detection method that does not require pretreatment remains a challenge. This study developed a novel yellow carbon dots molecularly imprinted (YCDs@MIPs) polyvinylidene fluoride (PVDF) composite (YCDs@MIPs@PVDF) fluorescent membrane for rapid visual LC detection. This method required no pretreatments during analysis since the LC could be specifically adsorbed when the samples passed through the YCDs@MIPs@PVDF membrane, causing fluorescence quenching, while matrix-interfering components could be removed for the porous structure of the membrane. A smartphone was used for rapid visual LC detection based on membrane fluorescence color changes in a dark-box ultraviolet analyzer. In food with a 15 % PVDF content and 6 mL added YCDs@MIPs, LC was quantitatively detected in a broad concentration range (5–500 μg/L) with a limit of detection (LOD) of 0.039 μg/L to 0.16 μg/L, which was lower than the strictest EU2019/92 limit of 10 μg/L. The analysis time was reduced from over 8 h when using the GB 23200.121–2021 and GB/T20769–2008 national standard methods to 30 min, while the analytical procedure decreased from six steps to two. The visual detection strategy combining the YCDs@MIPs@PVDF composite fluorescent membrane with a smartphone provided a new rapid detection technique for composite membrane purification and fluorescence signal output function.