Extraction-Free Absorption Spectrometric Analysis of Dis-Solved Furfural in Transformer Oils

Dissolved furfural in transformer oil is the product of deterioration of insulating paper in transformer, and its content is a powerful chemical characteristic quantity to assess the aging of transformer insulation. This paper proposes a detection technique based on absorption spectroscopy for rapid on-site analysis of furfural content in transformer oil. Based on the chromogenic reaction between furfural with aniline under acidic condition, producing complexation products with strong spectral absorption. Then, utilizing a smartphone to carried out absorption spectroscopy analysis, so as to achieve on-site, simple but accurate determination of furfural concentration. The principle of the furfural chromogenic reaction is described in detail and the optical schematic of the smartphone spectrometer is demonstrated. Experimental results is consisted to the theoretical analysis, and a LOD of 25 μmol/L has been achieved. The method provided here would provide a powerful tool for way for low-cost and on-site diagnosis of furfural content in transformers.