Press Release

March, 2010

25 Years of excellence, the GERSTEL Cooled Injection System (CIS)

The most widely sold PTV inlet in the world

Since Martin and Synge invented gas chromatography (GC) in 1940, a steady stream of innovations has improved performance and reliability of GC instrumentation. The GC technique is one of the most widely used for the determination of volatile and semi-volatile organic compounds (VOCs and SVOCs). Among the significant developments along the way were the temperature programmed GC oven, capillary columns, selective detectors and modern sample inlets, such as the Programmed Temperature Vaporizer (PTV). The PTV improved performance by ensuring discrimination free analyte transfer to the GC column and enabling analyte concentration. The GERSTEL Cooled Injection System (CIS) with the patented septum-less head (SLH) was first introduced 25 years ago. Today, the 4th generation CIS is the most widely sold and installed PTV-type inlet in the world.
With the introduction of the 5890 GC in the 1980s, Hewlett Packard set itself firmly on the path to becoming the leader in GC. The 5890 GC was designed for capillary columns, it had a powerful autosampler and it was shortly to be equipped with Electronic Pressure Control (EPC) for the carrier gas, enabling optimized GC separation for analytes over a wide boiling point range. The advent of capillary columns and improved separations over a wide boiling range clearly exposed the limitations of the sample inlets available at the time. In hot inlets, solvents and volatile analytes would evaporate extremely quickly in an uncontrolled manner giving rise to discrimination and reduced recovery, especially for high-boiling compounds that would condense in unheated areas around the GC inlet, but also for thermally labile analytes.
In 1984, GERSTEL introduced the Cooled Injection System (CIS). The patented CIS is a Programmed Temperature Vaporizer (PTV), often referred to as a “Universal GC Inlet”. In contrast to permanently heated GC inlets, the CIS enables introduction of liquid sample at low temperature followed by programmed heating with controlled evaporation and transfer of analytes to the GC column. The result is better separation, improved recovery, lower detection limits, and more accurate quantitative results.
The description “Universal GC Inlet” refers to the unique flexibility of the CIS. It can be used for either hot or cold injection combined with split, splitless, or direct on-column analyte transfer. The CIS can be cooled to temperatures as low as – 180 °C making it uniquely suitable as cryo-trap for VOC analyte concentration in combination, for example, with Thermal Desorption. Additionally, the CIS performs Large Volume Injection (LVI) combined with solvent venting for automated analyte concentration from liquid samples leading to substantially lower limits of detection. Whenever complex or “dirty” samples must be analyzed, the CIS can be expanded with the Automated Liner EXchange (ALEX) option to enable uninterrupted routine analysis of large batches of “dirty” samples.
PTV injections and LVI analysis are mainly performed using cryogen-free peltier cooling. Depending on the required starting temperature, peltier, cryostat or cryogenic cooling can be used. At the other end of the temperature scale, the CIS 4 operates up to 450 °C for determination of SVOC, PAHs and some waxes. The high temperature version CIS 6 scales the heights up to 650 °C, enabling pyrolysis of polymers in suspension following initial evaporation of the solvent.
Whichever version the analyst is using, all CIS inlets are based on a patented heating system and optimized liner dimensions that provide uniform heating and linear heating rates across the entire temperature range for controlled evaporation and best possible results.

Among the benefits:

• Improved quantitation due to controlled evaporation and discrimination free analyte transfer.
• Improved limits of detection, improved identification and improved quantitation through sharper peaks.
• Lower background signal, no septum bleed, improved detection limits thanks to patented Septum-Less Head (SLH)
• Best possible transfer and recovery of thermally labile analytes due to patented heating system and freely programmable heating rates.
• Automated Liner Exchange (ALEX) for routine analysis of matrix laden or “dirty” samples.

For more information about this and other Product News Releases, please contact:

Kaj Petersen, Marketing Manager, GERSTEL GmbH & Co. KG
Phone:  +49 208 765 0327
E-mail:  kaj_petersen(at)gerstel.de