The Gas Auto-sampler (AS202) is a stand-alone device that delivers samples to the GC through a heated bridge, ensuring that samples are injected at the appropriate temperature. The heated pathway is purged with carrier gas between each sample injection, and a vacuum pump ensures an extremely low level of matrix cross-contamination (typically less than 50 ppm).
Samples are loaded into the AS202 oven, which can hold up to twelve 500cc sample cylinders or nine 1L cylinders. The shelves are removable and adjustable and can also be tilted to prevent injection of any residual liquids which then changes the setup to allow for a maximum of eight 500cc or six 1L cylinders.
Samples (1000 psig / 6895 kPa max) are automatically regulated during the purging sequence so the GC injects all samples and calibration blends at atmospheric pressure. The AS202 can also be configured to automate injection of samples that are already at atmospheric pressure.
The table below compares the GC analysis results for 2 mL samples of n-pentane and n-hexane at 100 psig in propane. In the first trial, the sample is sent to the GC from the AS202 at ambient temperature; in the second trial the AS202 heats the samples to 130°C before injection.
Wasson: Repeatability Comparisons - Heated vs. Unheated
