Reasons for analysis errors in gas chromatographs
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Our company uses gas chromatographs to analyze the components of liquefied gas, but the analysis results vary significantly between winter and summer, leading to disputes with the production department; we seek expert guidance
Except for the hydrogen flame ionization detector, all detectors in a gas chromatograph are sensitive to temperature changes; in particular, the thermal conductivity cell detector is highly affected by even slight temperature variations, which directly impact the detector’s sensitivity and stability. Therefore, the temperature control accuracy required for the detection chamber is better than ±0.1 degrees
The volume should take the effect of temperature into account
The key is to use calibration with relevant standard gas samples! Everything has been corrected; what deviations are left? ? ?
Your company doesn’t know which sampling method to use. Since you are dealing with liquefied gas, using gas sampling will lead to the problems you mentioned, as all the components in liquefied gas have different boiling points, and their distribution in the gas phase varies between summer and winter. Using liquid sampling might be better; of course, it’s best to use a liquid sampling valve. In our production process as well, we use substances with low boiling points, and in that case, liquid sampling yields better results.