Gas purifiers are essential because they assist 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 of the column. Gas purifiers are like plans to protect the instrumentation along with other analytical columns from different 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 is necessary to select the right grade of gases with different purity levels for proper used in gas chromatographic applications.
Selection of Right Gas Purifier to Suit Your Applications
Numerous kinds of gas purifiers can be purchased in the market. While some gas purifiers remove just one specific contaminant, other styles remove multiple contaminants simultaneously from the gas stream. headspace sampler must think about several factors through 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, skin tightening and, and moisture traps will be the most common purifiers found in most the gas chromatography (GC) applications. Oxygen traps are usually filled with metal catalysts. Oxygen is recognized 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 bigger 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 think about trap efficiency to some extent.
Activated charcoal possesses an increased capacity to trap larger hydrocarbons that are greater than C4, in comparison to smaller hydrocarbons, which are lesser than C4. Moisture traps are often packed with unique molecular sieves. When put through 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 able 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 wish to know how the contaminants affect the gas stream, you should follow the road that the carrier gas takes to find yourself in 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 various other fittings. Each one of these areas is a potential culprit to introduce contaminants in to the gas stream. This leads not only in degrading the outcomes of chromatography but additionally 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 will get degraded easily when they are exposed to 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.
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 are available as compact panels having multiple purifiers or single panel that has multi-absorbent capabilities.