Silver nanoparticles modified multi-pocket semi-funnel substrate for trace detection of pesticides and heavy metal Hg2+

A three-dimensional multi-pocket semi-funnel composite anodized aluminum template (AAO) substrate modified with silver nanoparticles (AgNPs@MPSF-AAO) was successfully constructed via two-step anodic oxidation, pore-expanding treatment, magnetron sputtering, and annealing. Using 4-aminophenylthiophenol (4-ATP) as the probe molecule, the substrate with the best SERS performance was prepared with 100-s sputtering followed by 3-h annealing, the detection limit was as low as 10 −14  mol/L, the logarithm of the concentration showed a good linear relationship with the Raman signal, and the enhancement factor was as high as 6.16 × 10 7 , with a relative standard deviation (RSD) of 7.3 %, showing excellent sensitivity and uniformity. The substrate achieved indirect detection of Hg 2+ through the specific reaction of Hg 2+ with the thiol group of 4-ATP, with low detection limit of 10 −9  mol/L. Moreover, the detection of pesticides (e.g., carbaryl and thiram) verified its practical application potential, offering an efficient solution for the rapid detection of trace harmful substances in industrial wastewater and environmental pollutants.