Is gas chromatography used to analyze glycerin?
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Either DB or OV columns can be used; I’m not sure which one is more suitable. Has anyone done glycerol analysis? Please give some advice! ! I think that the boiling point of glycerin (290 degrees) is higher than that of triglyceryl triacetate (258 degrees); since it’s a non-polar compound, the effect of polarity should be relatively small. Therefore, the retention time of glycerin should be longer than that of triglyceryl triacetate. Yet the results they presented show the exact opposite. Could that person explain what the reason is?
At present, we are using chemical analysis methods.
Personal understanding: In gas chromatography, the retention time of the analyte is not only related to its boiling point and polarity. The retention time is also related to factors such as the distribution coefficient of the substance in the stationary phase and temperature, making it quite complex. Moreover, the greater the polarity of the substance to be analyzed, the shorter its retention time on a non-polar column. So what you’re describing is quite normal.
In fact, the sample is instantly vaporized as soon as it enters the instrument; the sample in the chromatography column exists in gaseous form. What truly affects the peak shape, as mentioned on the third floor, is likely the distribution coefficient of the components in the sample relative to the stationary phase; moreover, different stationary phases have different distribution coefficients.
It’s possible, but it requires a derivative method. I’ve done it before; it takes just a few minutes to complete
The analysis of polyols is preferably carried out using chemical methods, such as liquid chromatography and other chemical analytical techniques. If gas chromatography is necessary, it is best to perform derivatization before analysis, as substances with high boiling points retain strongly on the gas chromatography column and have poor thermal stability; this not only affects the analysis results but also has a negative impact on the column.
How do I adjust the titration endpoint? ? I used a pH meter to determine the pH value for determining the endpoint of the titration, but the results from the duplicate samples differed significantly ? Where is the problem? ? ? ? ? ? ?