Analysis of Glycols

Importance of the Topic

Glycols such as ethylene glycol and propylene glycol are widely applied in industries ranging from automotive antifreeze formulations to pharmaceuticals and food processing. Accurate quantification of these compounds in complex matrices is critical for quality control, environmental monitoring and regulatory compliance. Gas chromatography with flame ionization detection (GC-FID) offers a robust approach for separating and measuring glycols at trace levels.

Objectives and Overview

This application note presents a streamlined GC-FID method for the separation and quantitation of ethylene glycol and propylene glycol using the Shimadzu SH-200 column. The aim is to demonstrate rapid, reliable analysis with minimal sample preparation, focusing on method reproducibility, sensitivity and ease of implementation in routine laboratory workflows.

Methodology and Instrumentation

The method employs a direct injection GC-FID setup with an inert mid-polarity capillary column optimized for glycol separation. Key parameters include:

• Column: SH-200, 30 m x 0.53 mm I.D., film thickness 1.00 μm
• Oven program: 80 °C (1 min), ramp 8 °C/min to 200 °C, hold 3 min
• Injection: direct, injector temperature 220 °C
• Carrier gas pressure: 68.9 kPa (10 psi)
• Detector: FID at 270 °C

Main Results and Discussion

The method achieves baseline resolution of ethylene glycol and propylene glycol in under 10 minutes. Typical retention times are approximately 4.2 minutes for ethylene glycol and 5.1 minutes for propylene glycol. The FID response is linear from low microgram per milliliter concentrations, providing sensitivity suitable for environmental and industrial QC applications. Chromatographic peaks exhibit sharp shapes and minimal tailing, reflecting the inert nature of the SH-200 column.

Benefits and Practical Applications

• High throughput analysis with short run time
• Excellent sensitivity and linearity for trace quantitation
• Robust column performance with minimal maintenance
• Direct injection simplifies sample preparation
• Applicable to environmental monitoring, pharmaceutical QC and industrial process control

Future Trends and Potential Applications

Advances may include coupling the method with mass spectrometric detection for enhanced specificity, automated sample handling systems to boost throughput, and development of greener carrier gases or stationary phases. Expanding the method to multicomponent mixtures containing higher glycols and co-solvents will extend its utility across emerging industries.

Conclusion

The presented GC-FID method using the SH-200 column offers a fast, sensitive and reproducible approach for analyzing ethylene glycol and propylene glycol. Its straightforward implementation and reliable performance make it well suited for routine environmental and industrial laboratories.

Instrumental Setup

• Gas chromatograph: Shimadzu GC system
• Column model: SH-200 (P/N 227-36191-01)
• Temperature program: 80 °C (1 min) → 8 °C/min → 200 °C (3 min)
• Injection mode: direct, 220 °C
• Detector: FID at 270 °C
• Carrier gas: pressure set at 68.9 kPa (10 psi)