Analysis of Methanol in Transformer Oil Based on Extraction and Silver Nanosubstrate

Currently, the method of detecting methanol in transformer oil by surface-enhanced Raman spectroscopy (SERS) possesses the disadvantages of high cost, long time, and difficulty in field testing. To tackle this problem, a novel method was proposed for the combination of extraction and silver nanosubstrate to detect dissolved methanol in transformer oil. Specifically, it was determined first by Gauss view and Gaussian software that pure water and silver nanoparticles (Ag NPs) were applicable for the detection of methanol content by the Raman spectroscopy. Then, multilayer Ag NPs were synthesized on the surface of the copper sheet by a displacement reaction. The electric field distribution on the surface of Ag NPs was analyzed by COMSOL software, which further revealed that the Ag NPs could improve the Raman signal of methanol molecules. Finally, the pure water and Ag NPs were used for Raman measurement of methanol transformer oil solution with different concentrations based on the experimental platform of Raman spectroscopy. The results pinpointed that the minimum detection content of methanol in transformer oil was 1.8 mg/L. This method is simple, fast, low-cost, and applicable to the detection of trace methanol.