Abstract: In this paper, a method was established for the qualitative and quantitative determination of illicit sildenafil in health foods by surface enhanced Raman spectroscopy. By taking advantage of the specificity of Raman spectrum, we qualitatively determined sildenafil. Melamine was used as an internal standard to quantify sildenafil. Linear regression fitting was carried out using the peak height ratio between sildenafil at 1 234 cm-1 and melamine at 707 cm-1 as the y axis and sildenafil concentration as the x axis. Results indicated that a good linear relationship was observed in the concentration range of 0–50 mg/L with a correlation coefficient of 0.996 9. The limit of detection (LOD) was 0.05 mg/L, and the limit of quantitation (LOQ) was 5 mg/L. The recoveries of spiked solid and liquid samples were 85.6%–92.6% and 98.7%–105.2%, separately with relative standard deviations (RSD) of 4.14% and 3.25%, separately. In addition, this method was used to detect actual samples, and the results were basically consistent with those obtained by high performance chromatography-mass spectrometry (HPLC-MS). This method is accurate, sensitive and rapid, and can be used for the qualitative and quantitative detection of illicit sildenafil in health foods.

Key words: surface enhanced Raman spectroscopy, sildenafil, melamine, health foods, qualitative detection, quantitative detection