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 results. Further, such gas purifiers minimize detector noise and prolong the life of the column. Gas purifiers are like plans to safeguard the instrumentation and other analytical columns from different types of contaminants. Still, the gas purifiers will never be in a position to convert low purity gases into high purity gases. For this reason important factor, it’s important to select the right grade of gases with different purity levels for proper use in gas chromatographic applications.
Collection 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. You will need to think about 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, 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 recognized as probably the most detrimental contaminating gas in all analytical columns. Oxygen is with the capacity of producing irreversible oxidation damage, especially to polar stationary phases. Hydrocarbon traps are typically packed with activated charcoal, which can absorb organic compounds which are bigger than methane. Still, the molecular weight and size of the organic contaminants could have a definite effect on the capability of the hydrocarbon trap to an excellent 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, compared to smaller hydrocarbons, which are lesser than C4. Moisture traps are usually filled with unique molecular sieves. When put through extensive heating, the crystalline structures are forced to lose 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 wish to know how the contaminants affect the gas stream, you must follow the path that the carrier gas takes to find yourself in 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 various 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 additionally shortens the life of the column of CG.
Major contaminants like oxygen, hydrocarbons, and moisture can handle wreaking havoc with the columns and detectors of CG. headspace sampler 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. Because the detectors actually ‘see’ these contaminants, the effect is baseline noises, spikes, and drifts.
You should install gas purifiers in a vertical position as wall mounted types to avoid channeling. Channeling occurs when you install the gas purifier in a horizontal position. Gas purifiers are available as compact panels having multiple purifiers or single panel which has multi-absorbent capabilities.