Nitriles, C1 – C4, hydrocarbons, C1 – C5

Significance of the Topic

Gas-phase analysis of low molecular weight nitriles and hydrocarbons is critical for environmental monitoring, industrial process control, and research into atmospheric chemistry. These compounds can indicate pollution sources, reaction pathways, or safety hazards when present at trace levels.

Objectives and Overview of the Study

This application note demonstrates the use of gas chromatography with an Agilent PoraPLOT Q column to separate 39 C1–C4 nitriles and C1–C5 hydrocarbons within a single 60-minute run. The study aims to validate a robust method for qualitative and quantitative analysis of these volatile analytes.

Methodology and Instrumentation

The method employs capillary gas chromatography under three temperature conditions: isothermal at 160 °C, isothermal at 100 °C, and a temperature ramp from 40 °C (2 min) to 115 °C at 20 °C/min. Hydrogen serves as carrier gas at 2 mL/min. A split injection (1:100) at 250 °C introduces 0.2 µL sample volumes, delivering 1–3 nmol per injection. Flame ionization detection provides sensitive quantitation.

Instrumentation Used

• Agilent GC system with capillary injector and FID
• PoraPLOT Q fused silica column (0.32 mm × 10 m, 10 µm film thickness)

Main Findings and Discussion

All 39 target compounds were resolved with baseline separation under at least one of the tested temperature conditions. The isothermal 160 °C program achieved the fastest runtime but reduced resolution for late-eluting species. The temperature ramp improved separation of higher boiling analytes. Retention times ranged from methane at early elution to cyclopropanecarbonitrile at the end, demonstrating the column's broad selectivity.

Benefits and Practical Applications

• Comprehensive profiling of small nitriles and hydrocarbons in environmental and industrial samples
• High reproducibility and sensitivity for trace-level detection
• Flexible temperature programming optimizes throughput and resolution

Future Trends and Opportunities

Emerging detector technologies such as mass spectrometry combined with advanced column chemistries may further enhance identification and quantitation. Automation and miniaturization efforts can facilitate in-field analysis and high-throughput screening.

Conclusion

The described GC method on a PoraPLOT Q column provides efficient separation and quantitation of a diverse set of low molecular weight nitriles and hydrocarbons. Its adaptability in temperature programming supports varied analytical requirements in research and quality control.

Reference

• Agilent Technologies, Inc. Application Note A00572, Nitriles C1–C4 and C1–C5 hydrocarbons, 2011