Analysis of Diethylene Glycol in Glycerin Using Brevis GC-2050

Importance of the Topic

Diethylene glycol contamination in pharmaceutical and personal care products poses serious health risks. Reliable detection in glycerin matrices is essential to ensure compliance with pharmacopeial standards and protect public health.

Study Objectives and Overview

This study demonstrates the analysis of diethylene glycol in concentrated glycerin using the compact Brevis GC-2050 system. The method aligns with the Japanese Pharmacopoeia requirements, emphasizing high resolution and reproducibility.

Methodology and Instrumentation

The sample was prepared by dissolving 50 milligrams each of ethylene glycol, diethylene glycol, and glycerin in 100 milliliters of methanol. Analysis was performed using split injection at 250 degrees Celsius. The column used was SH-1701 with dimensions 30 meters by 0.32 millimeters and a film thickness of 1.0 micrometers. The oven temperature program ramped from 100 to 220 degrees Celsius at 7.5 degrees per minute with a 13-minute hold. Helium was used as carrier gas at a linear velocity of 38 centimeters per second. Injection volume was 1 microliter and split ratio set to 1 to 20.

Instrumentation

The analysis employed Shimadzu Brevis GC-2050 coupled with AOC-30i autosampler. Key components included the SH-1701 capillary column and split/splitless injection unit. Detector and injector temperatures were maintained at 250 degrees Celsius to accommodate high boiling analytes.

Results and Discussion

System performance testing showed chromatographic resolution far exceeding pharmacopeial criteria. The resolution between ethylene glycol and diethylene glycol was 67.3 compared to the required minimum of 40, while the separation between diethylene glycol and glycerin reached 19.7 versus the threshold of 10. Reproducibility tests over six injections yielded relative standard deviations below 1.2 percent for both diethylene glycol and glycerin, indicating excellent precision. The overlay of chromatograms confirmed consistent retention times and peak areas.

Benefits and Practical Applications

The compact footprint of the Brevis GC-2050 enables laboratories to increase throughput by installing multiple units without sacrificing analytical performance. The method ensures rapid, reliable quantification of diethylene glycol in glycerin, supporting quality control in pharmaceutical manufacturing.

Future Trends and Opportunities

Advancements may include coupling with mass spectrometry for enhanced specificity, integrating automated sample pretreatment for high throughput screening, and expanding applications to related polyol contaminants. Miniaturization and networking of multiple systems promise streamlined real time monitoring in production environments.

Conclusion

The validated GC method on the Brevis GC-2050 system delivers robust separation, high precision and compliance with pharmacopeial standards for diethylene glycol analysis in glycerin. Its compact design and performance make it suitable for routine quality control and research laboratories.