Highly sensitive detection of thiram residues on fruit peel surfaces using a filter paper-based SERS sensor with AgNWs@ZIF-8

The widely used pesticide thiram is found in various environments and foodstuffs, posing a risk to human health and contaminating the environment. In this work, the novel SERS flexible sensor (FP/AgNWs@ZIF-8) consisting of silver nanowires and zeolite imidazole frameworks combined with filter paper was prepared for the sensitive and rapid detection of thiram on fruit peel surfaces. The effect that different coating cycles of ZIF-8 films exert on the Raman signal enhancement of the sensor was investigated. The results show that optimal Raman response to 4-Aminothiophenol (4-ATP) was demonstrated in the FP/AgNWs@ZIF-8(5) sensor, with a low LOD of 1.6 x 10-15 M due to a coating period of 5. Furthermore, a novel SERS FP/AgNWs@ZIF-8 sensor with a porous and flexible structure on low-cost and eco-friendly paper was obtained, as to be immersed in a solution of thiram or wiped on a nectarine skin surface, and the highly sensitive LODs of 1.4 x 10-12 M and 7.4 fg/cm2 were achieved, respectively. Therefore, this facile, rapid, and sensitive flexible sensor at low-cost has excellent potential for pesticide residue detection and environmental toxicity analysis.