Process Gas Chromatographs are Purpose-built gas monitors which provide specific information, both qualitative species and quantitative amount, concerning the composition of a gas flow or sample found in a commercial or atmospheric system. Procedure GC’s, unlike Laboratory-based GC’s, are usually configured and used for static applications where the operator needs routine information regarding a specific set of target chemicals over long intervals. Procedure GCs are primarily designed to function as standalone, low maintenance gas analysers and typically do not require chemical or technical backgrounds to operate.
Procedure GCs also typically contain Analog and digital inputs and outputs which allow them to interface with external triggers, data collection systems and other onsite controllers. Procedure GC’s find applications in Many companies such as: Oil and Gas Exploration, Outdoor Air Quality Monitoring, Fugitive Emission detection and monitoring and Specialty Gas supply. The basic elements of gas chromatography are rather straightforward and together, make a powerful tool to specifically analyse one or more gases. There are 4 steps to a chromatographic analysis: sample collection, sample injection, sample separation, and sample detection. A gas chromatography sample is accumulated and then it is introduced into an inert gas flow called a carrier gas. The carrier gas moves conveys the gas sample through a column or sequence of columns where the gases from the sample are separated. Following the gases of interest have been separated out of the pillar, they are led to a detector that provides an output proportional to their concentration. A GC analysis might be a manual procedure or an automated online process.
Samples are ready for analysis with a selection of different procedures. Fixed sample loops are the system of choice for automatic procedure analysis Picture 1. Other common techniques vary from simply collecting a gas sample in a gas syringe, to more elaborate methods like volatilizing a liquid into a gas, pre-concentrating on a collection media, or cryogenically condensing a gas sample. A Sample may be manually injected into the carrier gas by means of a syringe, but is typically introduced by way of a sample loop and analytical valve which are in-line with the carrier flow. Regular carrier gases include nitrogen, helium, argon and, sometimes, hydrogen or air. Normally, the better the quality of the carrier gas the higher the analytical results. In automatic tools, the carrier gas is changed consistent with the sample loop to find a precise, pre-determined period of time, injecting the sample on the column Picture 2. This cycle is typically repeated continuously in process GC analysis.