A paper-based SERS/colorimetry substrate for reliable detection

For on-site analysis, the combination of surface enhanced Raman scattering (SERS) and colorimetry, as a dual-mode detection, can effectively improve the accuracy of detection, and reduce the influence of instrument fluctuation, which greatly improves the accuracy and reliability of the results. However, the preparation of SERS/colorimetry substrates are usually time-consuming and costly, which limits their practical applications. In this paper, a hydrophobic paper-based SERS/colorimetry substrate can be prepared by a simple spraying method. The hydrophobicity is introduced by the structures formed with polydimethylsiloxane and polymethylmethacrylate, which leads to high detection sensitivity due to its enrichment effect. Moreover, the electrostatic interaction between Ag nanoparticles and the analytes further enhances the performance of SERS and colorimetry in detection of thiram and aspartame. It also provides a new method for the detection of aspartame with colorimetry. Finally, the detection limits of SERS and colorimetry for thiram and aspartame are 0.1 mg/L and 0.1 g/L, 1 mg/L and 0.1 g/L, respectively. The paper-based SERS/colorimetry substrate makes the results more reliable through dual-mode detection, which shows great potential in the detection of real samples.