Analysis of Dibenzyl Disulfide in Insulating Oil Using SCD

Importance of the Topic

Sulfur containing compounds in insulating oils can lead to corrosion and reduced reliability of electrical equipment. Monitoring dibenzyl disulfide a representative organic sulfur species helps in assessing oil health and preventing failures.

Objectives and Study Overview

This work demonstrates a gas chromatography method with sulfur chemiluminescence detection for quantifying dibenzyl disulfide in transformer insulating oil across a concentration range from 0.1 to 100 milligrams per kilogram.

Methodology and Instrumentation

The method uses a Shimadzu Nexis GC 2030 coupled to an SCD 2030 detector and an SH series SH-5 column 30 meters by 0.32 millimeter diameter with 0.25 micrometer film thickness. Key parameters include

• Injection mode split (ratio 5 to 1) at 275 degrees C with a volume of 1 microliter
• Helium carrier gas at linear velocity 45 centimeters per second
• Oven program from 90 to 275 degrees C at 10 degrees C per minute with 20 minute hold
• SCD furnace at 850 degrees C with hydrogen nitrogen oxygen and ozone for chemiluminescence reaction

Main Results and Discussion

Baseline separation of dibenzyl disulfide and diphenyl disulfide was achieved under the given temperature program. Calibration showed linear response with correlation coefficient above 0.999. The method provided low detection limits suitable for routine quality control of insulating oils.

Benefits and Practical Applications

The proposed approach offers high selectivity for sulfur species minimal matrix interference and rapid analysis times enabling:

• Routine monitoring of transformer oil condition
• Early detection of oil degradation products
• Improved maintenance scheduling

Future Trends and Opportunities

Advances may include automated sampling systems coupling with mass spectrometry for structural identification and miniaturized SCD modules for field deployable analysis enhancing real time oil health assessment.

Conclusion

The described GC SCD method enables reliable quantification of dibenzyl disulfide in insulating oils supporting predictive maintenance and ensuring transformer longevity.

References

1. Shimadzu Corporation Application News G334 First Edition September 2022