Process Gas Chromatographs are purpose-built gas monitors that provide specific data, both qualitative species and quantitative amount, concerning the composition of a gas flow or sample found in a commercial or atmospheric program. Procedure GC’s, unlike Laboratory-based GC’s, are usually configured and used for static applications where the operator needs regular information regarding a particular set of target compounds over long intervals. Procedure GC’s are primarily designed to operate as standalone, low maintenance gas analysers and typically do not require chemical or technical backgrounds to function.
Procedure GC’s also typically contain Analog and digital inputs and outputs which allow them to interface with external triggers, data collection systems and other onsite controls. Procedure GC’s find software in Many businesses such as: Oil and Gas Exploration, Outdoor Air Quality Monitoring, Fugitive Emission detection and observation and Specialty Gas supply. The fundamental elements of gas chromatography are quite straightforward and collectively, make a strong 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 sample is collected and then It is introduced into an inert gas flow referred to as a carrier gas. The carrier gas moves carries the gas sample through a column or sequence of columns in which the gases in the sample are separated. After the gases of interest have been separated from the pillar, they are directed to a sensor which provides an output proportional to their concentration. A GC analysis may be a manual process or an automated online procedure.
- Sample Collection — Samples are prepared for analysis with a range of different procedures. Fixed sample loops are the system of choice for automatic process analysis Picture 1. Other common techniques vary from just collecting a gas sample at a gas syringe, to more elaborate methods like volatilizing a liquid into a gas, pre-concentrating on a collection media, or cryogenically condensing a gasoline sample.
- Sample Injection — A Sample could be manually injected into the carrier gas using a syringe, but is typically introduced by means of a sample loop and analytical valve that are in-line with the carrier flow. Normal carrier gases include nitrogen, helium, argon and, on occasion, air or hydrogen. Typically, the better the quality of the carrier gas the greater the analytical results. In automatic tools, the carrier gas is changed consistent with the sample loop to get a precise, pre-determined time period, injecting the sample on the column Picture 2. This cycle is typically repeated continuously in procedure GC analysis.