Automated Short Path Thermal Desorption System
The PC Controlled Automated Short Path Thermal Desorption System is designed for the continuous and unattended thermal extraction of volatile and semi-volatile organics from solid, liquid and gas samples for analysis by GC and GC/MS. It is the most useful and versatile automated thermal desorption system on the market today.
The new AutoDesorb System is the automated sampling version of the patented SIS Short Path Thermal Desorption System. The system has been shown to be an invaluable tool in hundreds of different applications. It is designed for the automatic and unattended pickup, injection and thermal extraction of volatile and semi-volatile organics from solid, liquid and gas samples for analysis by GC and GC/MS.
The AutoDesorb System consists of the AutoDesorb Tower (which contains the sample analysis hardware), an Electronics Console (which contains a microprocessor and power supplies) and a PC Windows Software Package (which integrates into the Agilent ChemStation software).
The system is operated and controlled by a PC Windows based software package developed by SIS. The AutoDesorb System has been developed to operate within the Agilent (formerly Hewlett-Packard) ChemStation software package on the Agilent 6890 GC or Agilent 5973 GC/MS to provide for a seamless integration of the Agilent GC or MSD with the SIS AutoDesorb System. The latest version (AutoDesorb Model 2000) now works with the Agilent 5890 series GC (also Agilent 5971, 5972 and 5973) operating with the latest version of ChemStation under windows 95, Windows 98 or Windows NT.
The AutoDesorb Tower sits over the GC injection port, where it is utilized for the direct desorption of both volatile and semi-volatile samples into the GC injection port and column. Due to its “short path” of sample flow, this system overcomes the limitations of other desorption systems by eliminating transfer lines (which are easily contaminated by samples) and by providing the optimum delivery (and therefore maximum sensitivity) of samples to the GC injector via the shortest path possible, i.e. direct injection into the GC.
The desorption tube with samples for analysis is fitted with a desorption tube needle and attached to a connecting tube. Each connecting tube is sealed at the top with a spring loaded ball seal to prevent sample contamination. A Carousel permits 12 samples to be loaded for the unattended analysis of samples. When signaled by the PC from the ChemSation software, the system automatically locates the sample to analyze, loads the sample, and then using the prescribed desorption method injects and desorbs the sample into the GC. Samples can be run in any sequence using any previously saved method as specified by the Agilent ChemStation software.
The AutoDesorb® Model 2000 System
The AutoDesorb System uses the SIS patented “Short Path Thermal Desorption” technology. The “short path” provided by the desorption tube needle eliminates the short comings of other thermal desorption systems by providing for the maximum delivery (and therefore maximum sensitivity) of samples to the GC. Both the Purge & Trap technique and Direct Thermal Extraction technique can be used for the analysis of volatile as well as semi-volatile organics.
First, it enables the sample, which is trapped on an adsorbent media contained in a glass lined stainless steel tube (GLT desorption tube), to be subjected to rapid (ballistic) heating. The AutoDesorb System can desorb samples at temperatures up to 450º C and at ramp rates up to 100º C per minute. Desorption times can be set from 1 second to 99 minutes. Multi-step desorption block heater ramping with hold times can also be programmed.
Second, the desorbed component can be easily and efficiently transferred into the injection port of the gas chromatograph from a glass lined stainless steel sample tube and its associated injection needle. This provides for a short transfer path for the sample in an inert environment to minimize the degradation of labile sample components which often decompose upon contact with the hot catalytic metal wall surfaces of the transfer path of other systems.
Third, each sample has its own individual adsorbent trap and needle to eliminate the possibility of cross-contamination from sample to sample, thus preventing any “memory effect” due to overloading of the sample in the GLT desorption tube or due to residues from previous samples.
Fourth, the new automated system permits the unattended analysis of multiple samples thereby increasing the productivity of the laboratory.