A molecular-imprinted SERS sensor based on a silver substrate for the selective capture and sensitive detection of crystal violet in textile wastewater

Abstract

Banned or unsafe additives pose a significant threat to human health. Ag-based molecularly imprinted polymers (Ag@MIPs), as a surface-enhanced Raman scattering (SERS) substrate, were proposed as a quick, convenient, and label-free method for the detection of the unauthorized additive crystal violet (CV). The morphology, particle size, and crystal structure of the as-prepared Ag@MIPs were characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy. The prepared Ag@MIPs as an SERS substrate had an enhancement effect on CV, and the minimum detection concentration of CV was as low as 1.0 × 10⁻¹⁵ mol L⁻¹. Using methylene blue and malachite green as reference molecules, Ag@MIPs show excellent selectivity toward CV. Moreover, the composite exhibits high sensitivity and specificity for CV detection, and can be recycled at least five times while maintaining favorable stability. Both Ag and Ag@MIPs substrates exhibit high sensitivity, enabling the qualitative and semi-quantitative analysis of CV with satisfactory linear correlation. On this basis, Ag@MIPs are promising for the detection of CV in real samples and show great potential for broad practical applications.