Gas chromatography (GC) is undoubtedly one of the key analytical techniques used to separate and interpret chemical components in a mixture.
Gas chromatography is the process of separating compounds in a mixture by injecting a gaseous or liquid sample into a mobile phase. The sample is first injected into the inlet of the GC, where a steady flow of an inert “carrier gas” is used to move it through a packed column. As the sample passes through the column, the various components interact with the column material. Each component elutes at a different rate, depending on how strongly it interacts with the column. The outlet of the column feeds directly into a detector that characterizes the eluted compounds based on column retention time and signal strength. Eventually, the sample and carrier gas are vented out as waste.
Most experts will agree that it is critical the GC outputs accurate, repeatable results to ensure differences between two sample injections are only due to differences in chemical composition. Consequently, it is imperative to keep the flow rate of the carrier gas constant, as deviations disrupt the detection of chemical compounds.
It is easy to conclude that fast, precise, highly accurate mass flow controllers that can be used to deliver exacting inert gas flows to your GC column are needed. When these mass flow controllers are used, they provide valuable benefits to GC applications: Stable, low-flow control: Even in low flow conditions, mass flow controllers provide stable flow from zero to full scale within tens of milliseconds.
Flow-control valves include simple orifices to sophisticated closed-loop electrohydraulic valves that automatically adjust to variations in pressure and temperature. Gas chromatographs with fixed orifice valves require stable pressure control. A common solution is the OEM pressure controller (EPC-Series), which provide numerous benefits to GC applications, including:
As we all know, in gas chromatography applications, a single valve EPC is ideal for regulating straightforward applications such as using a pressure regulator to knock down inlet pressure off a gas bottle, providing volumetric flow control against a calibrated orifice, or controlling stability in any desktop analyzer, lab in a box, reactor, or sample preparer.
A portable mass flow meter is an accurate and versatile device that can verify the performance of a GC, such as the flow rate of the carrier gas. This flow rate in the gas chromatograph is essential to the performance accuracy of the instrument. It is often used to check mass flow, pressure, and volume measurement on the input and vent of the GC.
These meters offer numerous benefits including:
In conclusion, successful GC evaluation and optimization requires versatile measurement, accuracy and repeatability, stable low-flow control and high-quality performance. Contact one of our team so they can walk you through the best options for your process.
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