In chemistry, chromatography is a laboratory technique for separating a mixture into its constituents, either for analysis or preparative purification. During the mobile phase, the compound is dissolved in a gas. The solvent transports the mixture through a system and onto a material referred to as the stationary phase. The components of the mixture move between the mobile and stationary phases at different velocities, and this causes the components to separate.
What is Process Gas Chromatography?
Process gas chromatography is a method for collecting, separating, and analyzing chemical compounds involved in the gas phase of industrial processes.
What is a process gas chromatograph?
A process gas chromatograph is a gas monitor specifically designed to provide qualitative and quantitative measurements of gas sampled in an industrial or atmospheric setting. These devices are used for oil and gas exploration, to monitor air quality, detect emissions, and more.
A process gas chromatograph is distinct from a laboratory gas chromatograph. The process gas chromatograph is used for static applications and gathers frequent measurements over extended periods of time. Where a laboratory gas chromatograph may be used in singular instances as the samples must be transported to the laboratory.
Process gas chromatographs today are designed to be low-maintenance and user-friendly. Operators do not have to have chemical or technical expertise to use these stand-alone gas analyzers. Furthermore, process gas chromatographs are compatible with other data collection systems and controls through digital and analog input and output features.
Elements of Process Gas Chromatography
Process gas chromatography can be divided into collection, injection, separation, and detection. The diagram below shows the process of collecting a gas sample, injecting it into a carrier gas, moving the gas through a column where the components are separated, and then analyzing the components in the detector.
Sample Collection
In the sample collection phase, a few different methods are used to prepare samples for analysis. For automated process analysis, fixed sample loops are commonly utilized. Other options include using a gas syringe to collect a gas sample, volatilizing a liquid into a gas, or cryogenically condensing a gas sample.
Sample Injection
In the sample injection phase, a syringe can be used to manually inject a sample into the carrier gas. However, most commonly, samples are inserted using a sample loop and analytical valve connected to the carrier stream. Nitrogen, helium, argo, hydrogen, or air can be used as a carrier gas. The type of gas affects the quality of the analytical results. This process can be automated and repeated continuously.
Sample Separation
In the sample separation phase, the most important aspects of process gas chromatography are conducted. Sample separation happens in columns that are mounted inside an oven, in tightly controlled conditions, in order to manage consistency between analyses. There are different types of columns, but the most common type uses a molecular sieve to separate samples by molecule size. Small particles travel at faster speeds, and larger particles travel at slower speeds. Other types of columns separate particles based on boiling point, molecular weight, or polarity. In order to conduct specific types of separations of specific gasses, columns can also be customized with varying phase densities, tube bores, and lengths.
Sample Detection
In the sample detection phase, the separated gasses travel from the columns and go through a detector. Depending on the analytical specifications, detectors can measure gas concentration, composition, and more. The detector transmits an output signal that generates the gas chromatography peaks in a chromatogram. When measuring concentration levels, the higher the peak, the higher the concentration of the specific gas. In addition to depicting a graph that shows the concentration density, gas chromatography software can also incorporate a wide range of diagnostic, reporting, and output technologies.
Process Gas Chromatography Solutions
TechStar is your manufacturing representative for instrumentation, automation, and analytical products. In addition to offering a full range of devices, TechStar is also your partner for training and service. For over 20 years, TechStar has been a leader in innovation, value, and customer experience. Included within TechStar’s comprehensive offerings are best-in-class process gas chromatography solutions.
TechStar sells the advanced GC8000 that delivers important innovations in its gas chromatograph analytical capabilities. With the introduction of the GC Module concept, parallel chromatography is made practical. Additionally, the displays and data are organized in a visual manner that is simple to use, understand, and maintain. TechStar also sells the TA3000 gas analyzers that are configurable, highly sensitive, and powerful. The isothermal gas chromatograph can be configured with a reduction gas detector or flame ionization detector. The analyzer can measure as low as parts-per-billion levels.
When you are ready for the best process gas chromatography solution, contact TechStar!