Supplies - GERSTEL Cooled Injection System, CIS - Automated Liner EXchange, ALEX

Significance of the Topic

The GERSTEL Cooled Injection System (CIS) represents a versatile, programmable PTV-type inlet that addresses growing analytical demands for ultra-trace and large-volume injections in gas chromatography. Its ability to perform septumless injections up to 1000 µL, combined with flexible cryogenic cooling and precise linear heating, enhances analyte focusing, reduces discrimination and cross-contamination, and expands the range of sample types accessible, from volatile headspace gases to thermally labile high-boiling compounds.

Objectives and Overview of the Study

This document provides a comprehensive overview of the CIS design features, operational modes, available consumables and accessories, and the complementary Automated Liner Exchange (ALEX) system. It aims to guide analysts in selecting appropriate inlet configurations, liners and cooling options to optimize performance for diverse applications such as headspace sampling, thermal desorption, large-volume liquid injection and SPME.

Methodology and Instrumentation

• CIS programmable inlet offers septumless injection, integrated split/splitless functions and programmable temperature control from –180 °C to +650 °C.
• Cooling options include liquid CO₂, liquid nitrogen or Peltier modules for rapid cryo-focusing.
• GERSTEL MAS controller provides unified control of CIS, autosampler (MPS) and peripheral modules.
• Compatible with GERSTEL MPS autosamplers and other major brands.
• Wide range of glass and quartz liners and packed liners (siltek coatings, glass wool, quartz wool, beads, Tenax TA™, Carbotrap B™/C™, PDMS foam) tailored for cold split, solvent venting, headspace and large-volume PTV injections.
• ALEX system automates liner exchange in sequences of up to 98 liners, minimizing carry-over and maintenance downtime for high-throughput or dirty samples.

Main Findings and Discussion

• The combination of cryogenic trapping and programmed heating delivers discrimination-free transfer of analytes from volatile (C5) to semi-volatile (up to C40) ranges.
• Septumless sampling heads and GRAPHPACK® ferrule technology ensure leak-free connections and reduce background signals.
• Deactivated liners up to 275 °C (Siltek-coated up to 350 °C, quartz up to 650 °C) accommodate a broad spectrum of chemistries while preserving inertness.
• ALEX enhances reproducibility by replacing contaminated liners automatically, which is critical for sequences of particulate-rich or matrix-loaded samples.

Benefits and Practical Applications of the Method

• Ultra-trace analysis: handling sub-ppb concentrations through large-volume injection and analyte focusing.
• Flexibility: seamless switching between split/splitless, headspace, thermal desorption and on-column modes.
• Reduced downtime: automated liner exchange and robust consumables reduce manual interventions.
• Enhanced inertness: specialized coatings and packed liners minimize active sites and improve recovery of labile or polar analytes.
• Scalability: compatible with existing Agilent/HP GC systems and a wide range of autosamplers.

Future Trends and Possibilities for Use

• Integration of CIS/ALEX with AI-driven method optimization and real-time diagnostics.
• Development of novel inert liner coatings and hybrid materials for expanded temperature stability and reduced background.
• Miniaturized or flow-through versions for faster thermal equilibration and lower cryogen consumption.
• Enhanced compatibility with comprehensive two-dimensional GC (GC×GC) through dual-column adapters.
• Sustainable cooling solutions reducing reliance on liquid cryogens.

Conclusion

The GERSTEL CIS and ALEX systems deliver a highly adaptable and reliable GC inlet solution, enabling analysts to tackle a wide range of challenging sample matrices and trace analyses. Their programmable temperature control, cryo-focusing capabilities, inert consumables and automated maintenance features support improved sensitivity, reproducibility and throughput in modern analytical laboratories.

Reference

No external literature references cited in the original material.