Analyze xylene
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When analyzing xylene, the analysis results are quite different between using SE-30 column and PEG-20M column. What should be done to achieve the same results?
It has nothing to do with the chromatographic column, right? Can you guarantee that except for the different chromatographic columns, other conditions are absolutely the same? The chromatographic column only affects the resolution, unless the vapor resistance of the chromatographic columns is different, resulting in vaporization discrimination!
The polarities of the two columns are different. Some components of the sample may overlap on a certain column, or the peak order of the components may change. These may cause large differences in the analysis results. You can use the standard addition method to check whether this is the case.
What is the difference in the analysis results pointed out by the poster? Are the retention times inconsistent?
The difference in retention time is normal. Xylene has only weak polarity. The SE-30 column is a non-polar column, and the retention time of xylene in it is longer.； PEG-20M is a highly polar column, in which xylene will flow out quickly!
We use the area normalization method without correction. For example, the analysis result obtained by SE-30 analysis is 98. 5%, while it may reach 99 when analyzed using a PEG column. More than 5%, the national standard requires the use of a PEG-20M column. When analyzed on an SE-30 column, p-xylene and m-xylene form one peak. Does anyone have any good methods for analyzing xylene?