Abstract:In order to effectively prevent the illegal addition of meloxicam in Chinese patent medicines and healthcare products, a sensitive, convenient and accurate method for detecting meloxicam was developed. Silver nanodendrite-modified silicon nanoarrays（AgNDs/SiNWs） were prepared by metal-assisted chemical etching and used as the enhanced substrate for surface-enhanced Raman spectroscopy. Meloxicam was utilized as the Raman probe molecule. The Raman enhanced effect, reproducibility, reusability and storage stability were evaluated by optimizing the preparation and detection conditions. The HF-H2O2-H2O system was chosen as the etching solution. A two-step method was adopted with etching time of 25 min and silver plating time of 120 s, and 5 μL of meloxicam was subsequently added to AgNDs/SiNWs materials for Raman detection. The lowest detected concentration of meloxicam was determined to be 0.1 μg/mL, and the linear range of meloxicam concentration was between 0.1 to 25 μg/mL (y=8.688 7x+89.945 9, R2=0.992 3) at the Raman peak intensity of 1 160 cm-1. Meloxicam in a compound capsule of anti-rheumatic Chinese patent medicine was further tested using the above mentioned method. Results showed that no meloxicam was detected in all of the samples. It was indicated that the concentration of meloxicam was less than 16.7 μg/g, far below the legal additional level of meloxicam (7.5 mg/g). The recovery rate of meloxicam was between 80.0% to 112.4%, which again proved the feasibility of the developed method in practical sample detection of meloxicam.
