摘要
We present a multifunctional substrate of ultrathin-layer chromatography (UTLC) and surface-enhanced Raman scattering (SERS), which enables analytes separation and label-free detection simultaneously. This integrated substrate is composed of silicon nanowires array (SiNWA), decorated with silver nano-dendrites (AgNDs). This SiNWA is fabricated by a facile and low-cost metal-assisted chemical etching process, and the AgNDs are then decorated onto SiNWA by chemical reduction process. These AgNDs provide abundant hot spots by inducing strong localized electric field, which is confirmed by finite-difference time-domain simulation calculations. With the optimized multifunctional substrate, the screening of melamine is successfully validated. The high linear dependence of signal intensity and melamine concentrations from 15 to 1,500 ppm with small deviation was carried out by our developed UTLC–SERS substrate, providing a great potential for quantitative detection. Besides, the SERS signals further show a low relative standard deviation of 8.7%, benefited from the calibration by a peak located at 520 cm −1 of silicon. In short, such a low-cost, high-stable multifunctional substrate of UTLC and SERS can be readily employed for practical applications of rapid biochemical mixture screening.