Rapid and sensitive detection of sodium saccharin in soft drinks by silver nanorod array SERS substrates

Abstract Sodium saccharin (SS) is a commonly used synthetic sweetener in carbonated soft drinks and beverages. Long-term consumption of SS could result in health problems. Here, a sensitive surface-enhanced Raman spectroscopy (SERS) method with silver nanorod (AgNR) array substrates was explored for quantification of SS in soft drinks. The AgNR array substrates fabricated by an oblique angle deposition technique exhibited an excellent SERS activity with an enhancement factor of ∼108. A good linear relationship was demonstrated between SERS peak intensity and SS concentration in the concentration range of 0.5–100 mg/L, and a limit of detection was determined to be 0.3 mg/L. The detection of SS in different soft drinks was further explored by combining SERS spectra with the partial least squares discriminant analysis. The results showed that the LODs of SS from Sprite, Cola, Fanta and Schweppes detected by SERS were 20, 5, 20 and 10 mg/L, respectively, which was far below the national standard. This SERS-based method enables the rapid and highly sensitive detection of SS with minimal sample pretreatment, and holds great promise in this food safety application.