Agilent Capillary Flow Technology

Significance of the Topic

The precise management of carrier and makeup gas in gas chromatography is essential for achieving high-resolution separations, reproducible retention times and extended column life. Capillary Flow Technology (CFT) components address common challenges in modern GC workflows by minimizing dead volume, improving inertness at high temperatures and enabling advanced techniques such as splitting, Deans switching and backflushing.

Objectives and Overview of the Document

This application note presents the design, functionality and performance characteristics of CFT fittings and devices. It reviews the types of CFT components available, outlines their typical analytical uses and demonstrates how they integrate with standard GC platforms to enhance analytical throughput and reliability.

Methodology and Instrumentation

CFT plates are manufactured by photolithography and chem‐milling to produce precision microfluidic channels and specialized ferrules. The devices are designed to reduce dead volume and improve gas flow control.

• Plate technology: photolithography and chem‐milling for micro-channels
• Ferrules: single-piece metal designs for superior inertness and high-temperature stability
• Gas control modules: PSD (Pulse Split Distributor), AUX EPC (Auxiliary Electronic Pressure Control), PCM (Pneumatic Control Module)

Main Results and Discussion

CFT devices support a variety of configurations:

• Two- and three-way splitters—unpurged and purged—for dividing column effluent between detectors or columns, with backflush capability and dilution control.
• Deans switching—for selective diversion of analyte bands between two GC columns or detectors using a solenoid-driven purge gas arrangement.
• Backflush systems—pre- or postcolumn configurations that remove high-boiling matrix components to protect analytical columns and detectors while reducing cycle times.

Performance evaluations demonstrated stable retention times, minimal peak distortion and efficient removal of late-eluting compounds. Example applications include blood alcohol analysis and hydrocarbon speciation in gasoline.

Benefits and Practical Applications

CFT offers multiple advantages in routine and specialized GC analyses:

• Low dead volume connections for optimal peak shape
• Enhanced inertness at temperatures above 300 °C
• Modular designs compatible with existing GC inlets and detectors
• Flexibility to implement backflushing, splitting and switching without manual reconfigurations
• Improved throughput in QA/QC laboratories and complex multi-dimensional separations

Instrumentation Used

• Agilent 8890 or Intuvo GC system
• PSD module
• AUX EPC or PCM module for gas flow control
• Standard FID, ECD, NPD and other GC detectors

Future Trends and Opportunities

Advances in microfabrication and materials science will drive the next generation of CFT components. Anticipated developments include integrated flow sensors, automated valve control via software, and expansion into GC×GC applications. These innovations will further streamline method development and support high-throughput screening in environmental, forensic and petrochemical analysis.

Conclusion

Capillary Flow Technology devices provide robust, low-dead-volume solutions for gas chromatography, enabling enhanced method flexibility and improved analytical performance. Their compatibility with standard GC platforms and ability to implement advanced techniques such as Deans switching and backflushing make them valuable tools for modern analytical laboratories.

Reference

No external references were provided in the source document.