Headspace-SERS method for rapid on-site detection of methylarsenates in water based on Cu-Ag substrate
Article
Tian, K, Zhang, M, Zhang, Q et al. (2025). Headspace-SERS method for rapid on-site detection of methylarsenates in water based on Cu-Ag substrate
. 44(6), 2068-2078. 10.7524/j.issn.0254-6108.2025031402
Tian, K, Zhang, M, Zhang, Q et al. (2025). Headspace-SERS method for rapid on-site detection of methylarsenates in water based on Cu-Ag substrate
. 44(6), 2068-2078. 10.7524/j.issn.0254-6108.2025031402
Currently, the analysis of methylarsenates relies on large-scale precision instruments, making on-site detection challenging. Surface-enhanced Raman spectroscopy (SERS), as a nondestructive in situ detection technique, can be used to detect trace methylarsenate in the environment. In this study, a simple metal displacement method was employed to prepare a copper mesh-silver dendrite SERS substrate. Based on this substrate, a portable SERS analysis device was developed to achieve rapid and on-site detection of methylarsenate through headspace method for the first time. The effects of installation conditions, HCl and KBH4 concentrations, and the volume of methylarsenate solution on SERS detection were investigated. The results showed that under stirring and heating at 60 °C, the optimal detection time was 10 min, with the best concentrations of HCl and KBH4 being 0.2 mol·L−1 and 0.6 mol·L−1, respectively, and the optimal volume of methylarsenate solution being 20 mL. MMAA (622 cm−1) and DMAA (596 cm−1 and 614 cm−1) could be distinguished by their characteristic peak positions, with MMAA achieving a detection limit as low as 1.29 µg·L−1. Performance tests demonstrated that the SERS substrate exhibited excellent uniformity, stability, and batch repeatability. Furthermore, when applied to actual water samples from different regions, the MMAA recovery rate ranged from 95.6% to 102.6% and the relative standard deviation (RSD) ranged from 4.5% to 6.6%. The SERS-based detection results were comparable to those obtained using liquid chromatography-hydride generation-atomic fluorescence spectrometry (LC-HG-AFS), confirming that this portable SERS device is suitable for on-site detection of methylarsenate in water.
