GASLESSTM PORTABLE GC's from SRI INTRUMENTS

SRI has introduced a new line of portable GCs which operate without the need of any external gas sources. The new Gas-less^TM GCs from SRI exploit the fact that a CCD (Catalytic Combustion Detector) can operate on air alone without the need for any other gases. Combined with the ability of many columns to tolerate air carrier gas, it is now possible to perform many GC applications using only room air and the built-in "whisper quiet" air compressor mounted inside the SRI GC chassis.

THE DETECTOR:

• CCD: The Catalytic Combustion Detector ( CCD ) consists of a platinum wire coil embedded in a ceramic matrix. A electric current passing through the platinum wire raises the temperature of the ceramic matrix to a temperature sufficient to combust hydrocarbons which impact the hot surface. The heat of combustion further elevates the temperature of the platinum wire which causes a change in the resistance of the wire, producing a voltage proportional to the mass of hydrocarbon analyte.

The advantages of using room air are:

1) Lower operating costs-air is essentially free.
2) Mobility-no gas cylinders need to be transported.
3) Safety-no flammable gases.

The obvious disadvantages are:

1) Interferences-background organics and water may impact some analyses.
2) Higher detection limits-some of the air compatible detectors are less sensitive using air than when using helium, hydrogen or nitrogen as carrier gas.
3) Lower maximum column temperatures-non-polar capillary columns can not be operated above 200ºC using air carrier. Polar capillary columns can not be used above 100ºC.
4) Analyses may take longer-since air's optimum linear velocity is lower than helium.
5) Extra time may be required to bake out the air filter-dryer at the end of each analysis.

Gasless^TM GCs

All SRI Gas-less^TM GC's are equipped with the built-in Model 203 PeakSimple data system which provides powerful yet easy data acquisition and temperature programming for the column oven.

The Gas-less^TM Educational Model GC is configured on the ultra compact 310 chassis and includes:

The Gas-less^TM Educational GC Models are ideal for teaching situations where the principles of chromatography are demonstrated on the same equipment the students will encounter in industry. All Gas-less Models include a built-in "whisper quiet air compressor" and a CCD detector which detects combustible (hydrocarbon) molecules only, but which can operate on air carrier gas from the internal air compressor. This configuration is ideal where compressed gas cylinders can not be used due to safety restrictions or budgetary limitations. Because the Gas-less GCs operate on their own infinite supply of room air, GC demonstrations can be performed in the classroom instead of the lab. Unlike GC's which require helium carrier gas, with the ongoing cost of cylinder rental, storage, and gas consumption, operation of the Gas-less GC models is essentially free except for the minimal cost of electricity. Two Gas-less Educational Models are available. Both are identical except that the less expensive version does not include the fast cool-down fans and circuitry. On this model, the column oven will cool-down slowly unless the oven lid is manually raised. The more expensive model with the fast cool-down fans will cool automatically at the end of the analysis from 250ºC to 50ºC in less than 5 minutes.

Send mail to Webmaster@quadrexcorp.com with questions or comments about this web site.
Copyright © 2002 Quadrex Corporation
Web Site Designed By Bob White From Duet Productions Ltd.