Determination of Sulfite in Botanical Medicine Using Headspace Thin-Film Microextraction and Surface Enhanced Raman Spectrometry

Abstract

A facile method using headspace thin-film microextraction (HS-TFME) coupled with surface enhanced Raman spectrometry (SERS) has been developed for the determination of sulfite in traditional Chinese herbal medicine. The extraction substrate was synthesized by depositing urchin-like ZnO micron particles on glass sheets using chemical liquid phase deposition. Under the optimal conditions, the intensity of the SERS signal at 630–640 cm⁻¹ provided a good linear relationship with the concentration of sulfite from 25 to 400 mg/kg, and the linear correlation coefficient (R) was 0.996 with a detection limit of 6 mg/kg. The method was employed for the determination of sulfite in herbal medicines, and the results were confirmed by a traditional distillation-titration method. Therefore, this developed HS-TFME-SERS method may play an important role in the rapid, simple, and selective determination of sulfite residues in Chinese herbal medicine and become a potentially universal method for this analyte in various solid samples.

Keywords:

• Headspace thin-film microextraction (HS-TFME)
• scanning electron microscopy (SEM)
• surface enhanced Raman spectrometry (SERS)
• transmission electron microscopy (TEM)
• X-ray diffraction (XRD)

Additional information

Funding

This study was supported by the Natural Science Foundation of Fujian Province under Grant No. 2015J01058 and the National Foundation for Fostering Talents of Basic Science under Grant No. J1310024.