Gas purifiers are necessary because they assist in providing a clean gas stream, that may guarantee the quality of the gas chromatographic analysis and the reliability of the outcomes. Further, such gas purifiers minimize detector noise and prolong the life span of the column. Gas purifiers are like insurance policies to safeguard the instrumentation along with other analytical columns from several types of contaminants. Still, the gas purifiers will not be able to convert low purity gases into high purity gases. Because of this important factor, it’s important to select the right grade of gases with different purity levels for proper used in gas chromatographic applications.
Collection of Right Gas Purifier to fit your Applications
Numerous kinds of gas purifiers can be found in the market. Although some gas purifiers remove just one specific contaminant, other types remove multiple contaminants simultaneously from the gas stream. You must reflect on several factors during the selection procedure for gas purifiers, taking into consideration your specific applications. These factors will include 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 Found in Gas Purifiers
Oxygen, hydrocarbon, skin tightening and, and moisture traps are 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 typically filled with activated charcoal, which can absorb organic compounds which are larger than methane. Still, the molecular weight and size of the organic contaminants could have a definite influence on the capability of the hydrocarbon trap to an excellent extent but it will also reflect on trap efficiency to some extent.
Activated charcoal possesses a higher capacity to trap larger hydrocarbons which are greater than C4, in comparison to smaller hydrocarbons, which are lesser than C4. headspace sampler are usually 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 may fit the cavity. Water fits perfectly into this cavity but this trap will also be able to remove gases like carbon dioxide, sulfur dioxide, hydrogen chloride, and chlorine or other gases which have effective diameters lesser than water.
Procedure for Contaminants Affecting Gas Stream
If you wish to know how the contaminants affect the gas stream, you need to follow the path that the carrier gas takes to get into the gas chromatograph. This path is applicable for detector fuel gases also. The gases start 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. Each one of these areas is a potential culprit to introduce contaminants into the gas stream. This leads not merely in degrading the results of chromatography but additionally shortens the life span of the column of CG.
Major contaminants like oxygen, hydrocarbons, and moisture can handle wreaking havoc with the columns and detectors of CG. The packed and capillary columns will get degraded easily when they face oxygen or moisture, especially at high temperatures. These contaminants may also compromise detector performance. Since the detectors actually ‘see’ these contaminants, the result is baseline noises, spikes, and drifts.
It is advisable to install gas purifiers in a vertical position as wall mounted types to avoid channeling. Channeling occurs once you install the gas purifier in a horizontal position. Gas purifiers can be found as compact panels having multiple purifiers or single panel which has multi-absorbent capabilities.
