Rapid screening of phthalates in edible oils by surface-enhanced Raman spectroscopy technology

To establish a method for rapid screening of phthalates (PAEs) in edible oils by surface enhanced Raman spectroscopy (SERS). PAEs was reduced to terephthalic dihydrazide using hydrazine hydrate to enhance its hydrophilicity, and then combined with Au nanoparticles (AuNPs) to produce Raman spectroscopy enhancement effect, which was determined. The reliability of the method was confirmed by comparing with SERS spectra of hydrophilic modification product derived from PAEs and terephthalic dihydrazide standard solutions. The optimum reaction conditions of hydrophilic modification and Raman spectroscopy were further explored, and the reaction temperature, time, amount of hydrazine hydrate and concentration of coagulant were determined. In the range of 1–100 µg/mL, the characteristic peak intensity at 1375 cm−1 showed a linear relationship with the concentration of PAEs, the correlation coefficient (r) was 0.999, and the limit of detection was 0.1 µg/mL. The method was used for rapid screening of PAEs in edible oils samples, with PAEs concentration of 10, 50 and 100 mg/kg. The screening results were positive, achieving a detection rate of 100%. Thus, it can serve as a new method for daily production quality control and emergency detection of edible oil products.