Gas purifiers are necessary 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 span of the column. Gas purifiers are like insurance policies to protect the instrumentation and 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 proper grade of gases with different purity levels for proper used in gas chromatographic applications.

Selection of Right Gas Purifier to Suit Your Applications

Various types of gas purifiers are available in the market. While some gas purifiers remove just one specific contaminant, other types remove multiple contaminants simultaneously from the gas stream. You need to think about several factors through the selection procedure for gas purifiers, taking into consideration your specific applications. headspace sampler will include the potential contaminants present in the gas stream, the limitations on flow and pressure, levels 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 are the most common purifiers found in majority of the gas chromatography (GC) applications. Oxygen traps are usually packed with metal catalysts. Oxygen is considered as the most detrimental contaminating gas in all analytical columns. Oxygen is capable of producing irreversible oxidation damage, especially to polar stationary phases. Hydrocarbon traps are typically packed with activated charcoal, which can absorb organic compounds that are larger than methane. Still, the molecular weight and size of the organic contaminants could have a definite influence on the capacity of the hydrocarbon trap to a great extent but it may also think about trap efficiency somewhat.

Activated charcoal possesses a higher capacity to trap larger hydrocarbons that are greater than C4, in comparison 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 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 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 want 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 really a potential culprit to introduce contaminants into the gas stream. This leads not only in degrading the results 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 face oxygen or moisture, especially at high temperatures. These contaminants will 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 can be found as compact panels having multiple purifiers or single panel which has multi-absorbent capabilities.

Uncategorized

Leave a Reply

Your email address will not be published. Required fields are marked *