Nylon membranes modified by gold nanoparticles as surface-enhanced Raman spectroscopy substrates for several pesticides detection

Abstract

Surface enhanced Raman spectroscopy (SERS) is an attractive means for trace compound detection because of its high sensitivity, however, the poor reproducibility is a major challenge. Herein, we propose a facile SERS strategy employing the several developed test processes to improve the repeatability of the SERS analysis based on regular nylon membranes as substrates to detect trace compounds. Various methods, including in situ reduction, immersion adsorption, and filtration, were first compared to prepare composite substrates using nylon membranes and gold nanoparticles. The substrates prepared by filtration showed the best test parallelism (RSD = 7.85%). Its limit of detection (LOD) could reach 10⁻⁸ g mL⁻¹ with a good linear relationship in the range 10⁻⁸ to 10⁻⁷ g mL⁻¹. Finally, three pesticide solutions were tested to verify the substrate applicability. A superior LOD of 10⁻⁸ g mL⁻¹ was observed for thiram, whereas the LODs of both phorate and benthiocarb could reach 10⁻⁶ g mL⁻¹. Overall, modifying nylon membrane substrates with gold nanoparticles improves the repeatability and economic viability of SERS and favors its wider commercial application for detecting trace compounds.