Introduction
Insulating paper is used in coil of electric transformer. Furfural is generated by deterioration of the paper. Measuring the amount of furfural allows to estimate the aged deterioration of electric transformer. So, this measurement is essential to maintain the product reliability.
In the previous article, measurements of furfural dissolved in transformer oil were performed with HPLC. This article shows the measurements of furfural using UHPLC, which has 0.1 mm I.D. tubing and semi-micro type cell to avoid the peak diffusion.
LC-4000 UHPLC system
Experimental
Column: Unifinepak C18 (2.0 mmID x 50 mmL, 1.9 µm)
Eluent : Water/Acetonitrile (85/15)
Flow rate: 0.5 mL/min
Column temp.: 40 ̊C
Detection: UV detection (278 nm)
Injection volume: 1 µL
Standard Sample: Furfural
Figure 1. Furfural
Keywords
Electric transformer, insulating paper, UHPLC, furfural, transformer oil, C18, UV detector
Results
Figure 2 shows the chromatogram of standard furfural under UHPLC conditions. As shown in figure 3, the correlation between area value and concentration keeps linearity in the concentration range from 0.1 to 50 µg/mL. The correlation coefficient is 0.9999.
As a result, using UHPLC allows to detect furfural in 1 min.
Figure 2. Chromatogram of 1 µg/mL standard furfural (1. Furfural)
Figure 3. Correlation between area and concentration of standard furfural
