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Gas purifiers are necessary because they assist in providing a clean gas stream, which can guarantee the quality of the gas chromatographic analysis and the reliability of the results. Further, such gas purifiers minimize detector noise and prolong the life span of the column. Gas purifiers are like plans to safeguard the instrumentation and other analytical columns from several types of contaminants. Still, the gas purifiers will not be in a position to convert low purity gases into high purity gases. For this reason important factor, it is necessary to select the proper grade of gases with different purity levels for proper use in gas chromatographic applications.

Selection of Right Gas Purifier to fit your Applications

Numerous kinds of gas purifiers can be purchased in the market. Although some gas purifiers remove just one specific contaminant, other styles remove multiple contaminants simultaneously from the gas stream. You should think about several factors during the selection procedure for gas purifiers, taking into consideration your unique applications. These factors includes the potential contaminants within the gas stream, the limitations on flow and pressure, degrees of gas purity required, desired convenience in replacement of spent gas traps, and space availability.

Common Traps Used in Gas Purifiers

Oxygen, hydrocarbon, carbon dioxide, and moisture traps will be the most common purifiers used in most the gas chromatography (GC) applications. Oxygen traps are usually filled with metal catalysts. Oxygen is considered as the most detrimental contaminating gas in every analytical columns. Oxygen is with the capacity of producing irreversible oxidation damage, especially to polar stationary phases. Hydrocarbon traps are usually packed with activated charcoal, which can absorb organic compounds that are larger than methane. Still, the molecular weight and size of the organic contaminants will have a definite influence on the capability of the hydrocarbon trap to a great extent but it may also reflect on trap efficiency to some extent.

Activated charcoal possesses a higher capacity to trap larger hydrocarbons which are greater than C4, compared to smaller hydrocarbons, which are lesser than C4. Moisture traps are often filled with unique molecular sieves. When subjected to extensive heating, the crystalline structures are forced to reduce their hydration or water content. This opens a cavity which gets filled readily with any compound that can fit the cavity. Water fits perfectly into this cavity but this trap may also be in a position to remove gases like skin tightening and, sulfur dioxide, hydrogen chloride, and chlorine or other gases which have effective diameters lesser than water.

Procedure for Contaminants Affecting Gas Stream

If you want to know how the contaminants affect the gas stream, you have to follow the road that the carrier gas takes to get into the gas chromatograph. This path does apply for detector fuel gases also. The gases begin from a gas tank or perhaps a special gas generator. The gas travels through long lengths of tubes, pressure gauges, valves, and different other fittings. headspace sampler of these areas is really a potential culprit to introduce contaminants in to the gas stream. This leads not merely in degrading the results of chromatography but also shortens the life span of the column of CG.

Major contaminants like oxygen, hydrocarbons, and moisture are capable of wreaking havoc with the columns and detectors of CG. The packed and capillary columns can get degraded easily when they face oxygen or moisture, especially at high temperatures. These contaminants may also compromise detector performance. Because the detectors actually ‘see’ these contaminants, the result is baseline noises, spikes, and drifts.

You should install gas purifiers in a vertical position as wall mounted types to prevent channeling. Channeling occurs once you install the gas purifier in a horizontal position. Gas purifiers are available as compact panels having multiple purifiers or single panel that has multi-absorbent capabilities.