The experimenters know that the gas chromatograph will have three major illnesses during use: “dirty, leaky, blocked”. According to statistics, 90% of GC's problems occur in the inlet. The self-supporting gas carries the sample into the liner, the split plate (which is only available in the SSL inlet), and the split outlet, which may cause “dirty” in all aspects.

First, the gas source

When the purity of the carrier gas does not reach 99.99%, it means that the gas is not pure, and may be mixed with tiny particulate matter, which may cause blockage of the EPC valve; if mixed with water, it will affect the analysis signal: the baseline is too high and the noise is too large.

Brainstorming: Use a gas purifier (replenishment enthalpy) to remove impurities such as moisture, oxygen and hydrocarbons from the carrier gas. The large capacity of 750cm3 eliminates the trouble of frequent replacement. After the effect of the collection is reduced, it can be automatically regenerated at high temperature.

Second, the liner

As the GC sample analysis increases, impurities adsorbed on the inner wall of the liner gradually accumulate. Lead to peak shape deterioration, sample decomposition or discrimination, poor reproducibility, ghost peaks, etc.

Brainstorming: 1) Use a solvent (ethanol/acetone) to drive into the inlet for cleaning. 2) Use inertia liner to reduce pollution adsorption.

Third, the split plate

For the split/splitless inlet (SSL), contaminants adsorbed on the splitter plate gradually accumulate due to the continuous impact of the sample gas during the splitting process, resulting in contamination. Lead to: peak shape deterioration, sample decomposition or discrimination, poor reproducibility, ghost peaks.

Brainstorming coupons: 1) regular cleaning; 2) gold-plated mats to reduce the amount of adsorption.

Fourth, the diversion exit

The separated sample gas passes through the split line and condenses due to a sudden drop in temperature. The impurities are adsorbed at the split outlet and block the diverter valve. Unlike the first two pollutions, the “dirty” of the split outlet will cause the inlet pressure to be abnormal, the retention time to shift, and the repeatability to be poor.

Brainstorming coup: 1) regular cleaning shunt conduit; 2) before the gas enters the sample splitter is connected EPC bulk gas purification device (Connaught pan complement hydrazine volume 20cm3, used brands are generally about 10 cm3), to avoid contamination EPC.

Although they are all “dirty”, the methods and effects are different. The pollution at the gas source and the split outlet can be avoided, and the pollution of the liner and the split plate can only be reduced and cannot be avoided.

Wuhan Jisi Instrument Equipment Co., Ltd. is committed to building the world's advanced level and suitable for domestic laboratory equipment, and is committed to tailoring the system's overall solution for your system. It is a one-stop supplier of large-scale laboratory services in Central China. It has provided professional laboratory equipment for more than 5,000 well-known domestic enterprises and institutions.

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