Analysis of Furanic Compounds (Furfural)

Significance of the Topic

Insulation oils used in electrical equipment undergo thermal and oxidative degradation over time. Furanic compounds such as furfural and related derivatives serve as sensitive indicators of oil aging and transformer health. Routine monitoring of these markers enables early detection of degradation, supports predictive maintenance, and helps prevent costly equipment failures.

Objectives and Study Overview

This application note presents a reversed-phase liquid chromatography method for the simultaneous determination of five key furanic compounds in insulation oil. The targeted analytes include:

• 5-Hydroxymethyl-2-furaldehyde (5HMF)
• Furfuryl alcohol (2FOL)
• 2-Furaldehyde (2FAL)
• 2-Acetylfuran (2ACF)
• 5-Methyl-2-furaldehyde (5MEF)

The study demonstrates method performance and chromatographic separation using Shimadzu’s Shim-pack VP-ODS column.

Methodology and Instrumentation

The analysis was conducted on a Shimadzu Prominence-i HPLC system under the following conditions:

• Column: Shim-pack VP-ODS, 250 mm × 4.6 mm I.D., 5 µm
• Mobile phase: A – water; B – acetonitrile
• Gradient program: 20% B (0–10 min) → 100% B (10.01–20 min) → 20% B (20.01–40 min)
• Flow rate: 1.0 mL/min
• Column temperature: 40 °C
• Injection volume: 15 µL
• Detection: Photodiode array at 220 nm and 280 nm
• Sample vials: TORAST-HTM glass vials

Main Results and Discussion

Under the optimized gradient, all five furanic compounds were baseline-separated within 10 minutes. The earliest eluting compound (5HMF) appeared around 2.2 minutes, while the last (5MEF) eluted at approximately 9.5 minutes. The dual-wavelength detection enhanced sensitivity and selectivity: 220 nm provided strong absorbance for most analytes, while 280 nm offered complementary detection for furfuryl alcohol. The method exhibited reproducible retention times and peak shapes, confirming column stability and suitable re-equilibration between runs.

Benefits and Practical Applications

This LC method offers several advantages for routine laboratory and field applications:

• Rapid analysis time with clear separation of multiple analytes
• Robust gradient program minimizes solvent use and extends column life
• Dual-wavelength detection improves quantification accuracy
• Applicability to quality control in transformer maintenance and oil recycling

Future Trends and Opportunities

Advancements may include the adoption of ultrahigh-performance LC columns for sub-5-minute runs, coupling with mass spectrometry for enhanced sensitivity and structural confirmation, and integration of automated sample preparation systems for higher throughput. Expansion of the target analyte list to include additional aging markers could further enhance diagnostic capabilities.

Conclusion

The described reversed-phase LC method on a Shim-pack VP-ODS column provides a reliable, efficient, and sensitive approach for monitoring furanic degradation products in insulation oils. Its rapid run time, robust performance, and dual-wavelength detection make it well suited for predictive maintenance and quality assurance programs.

Reference

• Shimadzu Corporation. Application News L562 (December 2021). Analysis of Furanic Compounds (Furfural) in Insulation Oil. ERAS-1000-0158A.