DETERMINATION OF DISSOLVED-GASES AND FURAN-RELATED COMPOUNDS IN TRANSFORMER INSULATING OILS IN A SINGLE CHROMATOGRAPHIC RUN BY HEADSPACE CAPILLARY GAS-CHROMATOGRAPHY

A static headspace/capillary gas chromatographic technique has been de veloped allowing dissolved gases and furan-related compounds in power transformer oils to be determined in a single chromatographic run. The simultaneous determination of these two classes of compounds from a s ingle sample injection represents a definite advantage over current pr ocedures for the detection of impending performance failure of the uni t. The method uses gas chromatography with porous-layer open tubular ( PLOT) columns and a valve operated in sequence for flowpath selection. Also, comparison with the current method using packed columns showed that dissolved-gas analysis with PLOT columns provides better peak sha pes and lower detection limits (S/N-b = 3): 5, 3 and 1 ppm (v/v) for h ydrogen, carbon oxides and light hydrocarbons respectively. Detection of 2-furaldehyde is possible down to 0.5 ppm (w/w).