Gas purifiers are necessary because they help in providing a clean gas stream, which can 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 protect the instrumentation along with other analytical columns from various kinds of contaminants. Still, the gas purifiers will not be in a position to convert low purity gases into high purity gases. Due to this important factor, it is necessary to select the proper grade of gases with different purity levels for proper use in gas chromatographic applications.
Collection of Right Gas Purifier to fit your Applications
Various types of gas purifiers are available in the market. While some gas purifiers remove just one specific contaminant, other styles remove multiple contaminants simultaneously from the gas stream. You should think about several factors through the selection process of 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, carbon dioxide, and moisture traps will be the most common purifiers used in majority of the gas chromatography (GC) applications. Oxygen traps are normally packed with metal catalysts. Oxygen is considered as the most detrimental contaminating gas in every analytical columns. Oxygen is capable of producing irreversible oxidation damage, especially to polar stationary phases. Hydrocarbon traps are usually filled with activated charcoal, that may absorb organic compounds which are larger than methane. Still, the molecular weight and size of the organic contaminants will have a definite effect on the capability of the hydrocarbon trap to a great extent but it will also think about trap efficiency somewhat.
Activated charcoal possesses an increased capacity to trap larger hydrocarbons that are greater than C4, compared to smaller hydrocarbons, which are lesser than C4. Moisture traps are usually filled with unique molecular sieves. When subjected to extensive heating, the crystalline structures are forced to reduce their hydration or water content. headspace sampler 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 that have effective diameters lesser than water.
Procedure for Contaminants Affecting Gas Stream
If you wish to understand how the contaminants affect the gas stream, you should follow the path 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 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 only in degrading the outcomes 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 if they are exposed to 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 prevent 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.