Gas purifiers are essential because they help in providing a clean gas stream, which can guarantee the grade 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 safeguard the instrumentation and other analytical columns from different types of contaminants. Still, the gas purifiers will never be able 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 used in gas chromatographic applications.
Collection of Right Gas Purifier to Suit Your Applications
Various types of gas purifiers are available in the market. Although some gas purifiers remove just one single specific contaminant, other styles remove multiple contaminants simultaneously from the gas stream. You must think about several factors during the selection procedure for gas purifiers, taking into consideration your unique applications. These factors will include the potential contaminants present in 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 will be the most common purifiers found in most the gas chromatography (GC) applications. Oxygen traps are normally packed with metal catalysts. Oxygen is recognized 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, 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 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. Moisture traps are usually packed 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 will also be in a position to remove gases like carbon dioxide, sulfur dioxide, hydrogen chloride, and chlorine or other gases which have effective diameters lesser than water.
Process of Contaminants Affecting Gas Stream
If you want 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 perhaps a special gas generator. The gas travels through long lengths of tubes, pressure gauges, valves, and different other fittings. Every one 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 additionally shortens the life 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 if they are exposed to oxygen or moisture, especially at high temperatures. These contaminants may also compromise detector performance. Since headspace sampler ‘see’ these contaminants, the effect 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 are available as compact panels having multiple purifiers or single panel which has multi-absorbent capabilities.