| The adulteration of traditional Chinese medicine (TCM) with synthetic drug severely does harm to TCM effect and the public health. So it is crucial for quick detection of synthetic drug found in TCM. Here, we report surface-enhanced Raman scattering (SERS) coupled with density functional theory (DFT) calculation for the direct identification and detection of aminopyrine (AP) in TCM using silver-coated gold nanoparticles (Au@Ag NPs). It has been demonstrated that the Raman enhancement of Au@Ag NPs to AP was stronger than those of Au, Ag and Ag@Au NPs, and there was a strong dependence of the Raman enhancement on the substrate concentration. Meanwhile, we obtained the DFT calculation result of AP, and found that the calculation result was in good agreement with the experimental one. In addition, the characteristic peak at 999 cm-1, which was the strongest peak in the SERS spectra, was used for the quantitative evaluation of AP level. The limit of detection (LOD) was 2.50×10-7 M (equal to 57.8 ng mL-1) in aqueous solution, which was in the same order of magnitude as that obtained by liquid chromatography-mass spectrometry (LC-MS) method, and the recovery of AP ranged from 93.9% to 101% in the spiked TCM (Shexiang Fengshi capsule) sample. Each test using the SERS sensor only needed a droplet of 10μL sample solution and whole test could be accomplished within ～3 min. The SERS technique can be applied to authenticate and detect trace AP in real herb product. |
PDF Full Text Request