Benzoic acid (BA) is widely used as an antimicrobial preservative in carbonated beverages. In this study, silica gel thin-film microextraction (TFME) coupled to surface enhanced Raman scattering (SERS) was applied for the rapid detection of BA in carbonated beverages. The TFME process was performed by placing small pieces of silica gel substrate in a simple homemade device, and then the content of BA was detected using SERS after colloidal gold was uniformly dropped onto the substrate. The obtained SERS signals of BA were strong and of high reproducibility. A good linearity between the concentration of BA and the SERS signal intensity at 994 cm⁻¹ in the range of 25–500 μg mL⁻¹ was obtained under optimal experimental conditions. The detection limit value was found to be 3.6 μg mL⁻¹ and the recovery of the spiked BA was in the range 85.0–103.0%. The developed method was successfully applied to detect BA in carbonated beverage samples as the results were consistent with those using high performance liquid chromatography, suggesting that it is a rapid, convenient and sensitive way to achieve BA detection in carbonated beverages.

苯甲酸（BA）被广泛用作碳酸饮料中的抗菌防腐剂。在这项研究中，硅胶薄膜微萃取（TFME）与表面增强拉曼散射（SERS）耦合用于碳酸饮料中BA的快速检测。TFME工艺是通过将一小片硅胶基材放在简单的自制设备中进行的，然后将胶体金均匀滴在基材上后，使用SERS检测BA的含量。获得的BA的SERS信号是强的并且具有高再现性。BA的浓度和在994厘米的SERS信号强度之间的良好的线性^-1中的25-500微克mL范围^-1是最佳实验条件下获得的。检出限为3.6μgmL^-1，加标的BA的回收率在85.0–103.0％的范围内。该方法成功应用于碳酸饮料样品中BA的检测，结果与采用高效液相色谱法的结果一致，表明该方法是实现碳酸饮料中BA检测的快速，便捷，灵敏的方法。