Reproducibility is still a great challenge for surface-enhanced Raman scattering (SERS), because the uncontrollable fabrication of SERS substrates or the uneven distribution of samples on the substrate result in the signal fluctuation with or between the substrates. Herein, a novel SERS quantitative method with good reproducibility was proposed. It is based on the basic principle that the SERS signal intensity is not only related to electromagnetic enhancement and the concentration of sample, but also related to the specific surface area of the substrate. The surface area information of the substrate is obtained through electrochemical technology, and then introduced into the standard curve with the linear relationship of concentration of sample and SERS intensity as a new variable to obtain a 3D standard curved surface, which effectively corrects the signal difference between the substrates, and combines the wide area Raman method to reduce the difference within the substrate, thereby improving the reproducibility of SERS quantitative detection. Using malachite green (MG) as the probe molecule and using cyclic voltammetry to calculate the substrate area fitted plane model (CV-standard curved surface), the root mean square error (RMSE) of the predicted result is 0.26 and the relative error (RE) is 0.25. It shows that the detection error significantly reduces comparing with the traditional standard curve method. Also, the proposed method can be used in other SERS quantitative detection and has potential application prospects.
The fabrication of paper-based SERS substrates, which provided the advantages of active Raman signal enhancement with good reproducibility is still a challenge for real-world applications. In this report, we showed how the SERS enhancement and reproducibility of Au NP paper substrates prepared by inkjet-printed method could be improved significantly by second growth of Ag NPs. The Au/Ag NP paper substrates fabricated with the improved protocol had a much higher SERS enhancement (about 1.356✕10 3 times) compared with printed Au NP paper substrates. Moreover, the reaction parameters affected the SERS enhancement of Au/Ag NP paper substrates were optimized by collecting rhodamine 6G (R6G) SERS spectra. Further, the reproducibility of Au/Ag NP paper substrates were evaluated on random spots of single substrate and batch to batch substrates by recording the intensity of R6G at 611 cm −1 . The SERS intensities at 611 cm −1 showed small relative standard deviation, which indicated the good reproducibility of Au/Ag NP paper substrates. This improved method enabled the printed Au NP paper substrates to possess the practical applicability for the on-site SERS sensing.
危险品化学品经营许可证（带存储）