The difference between chromatographic analysis and chemical analysis

Let’s not talk about the accuracy of the data here. In terms of accuracy, chromatographic analysis is much better than chemical analysis! We used the Ostenimeter to conduct this type of analysis in the early days, but gave up a long time ago. In terms of reliability alone, I believe that your chemical analysis will only have a simple systematic deviation if the analytical skills are up to standard and the sampling is accurate. This requires you to use the same sample, two methods in parallel for half a year, and follow up for two years. Then you can use instrumental analysis instead of chemical analysis. Of course, you have to have comparative data values. Without preliminary work and without personal observation, I think it is difficult to judge who is accurate and who is not. Personal opinion. This post was last edited by limingshuguang on 2009-3-9 12:38 ]

What column do you use for chromatography? Is CO2 produced together with other components? This post was last edited by limingshuguang on 2009-3-9 12:39 ]

I am not asking which result is accurate, but I want to analyze the reasons for the deviation of the results! Personally, I think the first three data are almost the same and can be considered accurate. However, the hydrogen in the chromatogram is subtracted and should be higher than the real value. It can be considered that the Ostenimeter is relatively more accurate. Similarly, for nitrogen, the chromatogram should be more accurate! The problem lies in methane. Methane and hydrogen are mixed with air and made explosively. The presence of carbon dioxide in the air will affect the results and make the methane results higher. But the problem is that the two results (0.6 and 1.2) are too different. This cannot be just the influence of this one. There should be other reasons. Please help analyze!

We use two stainless steel columns, one molecular sieve and one TDX-01. This post was last edited by zjs0536 on 2009-3-16 12:23 ]

Then in your chromatographic analysis method, each component is produced by external standards, and the results have a lot to do with the standard gas. As for the Osteni method, I have never done it before, so I don’t know if it requires a standard gas.

A set of data cannot explain anything at all. Even if the explanation is accurate, it can only be a guess. In order to establish a problem, you must first use many sets of data to establish the problem, and then talk about solving the problem. I always feel that your data is too random. Personal opinion. This post was last edited by limingshuguang on 2009-3-9 12:42 ]

First of all, the difference between your oxygen, carbon monoxide, and carbon dioxide is very small. From this perspective, these two methods are relatively reliable. Methane peaks in the chromatogram after carbon monoxide and before carbon dioxide, usually about 7 minutes. Due to the small concentration, there is sometimes a certain deviation during automatic integration. In the austenimeter, the explosion method is used to measure, and the error is larger, making comparison difficult. It is better to do it several times in the chromatogram and choose a quantitative value with better integration. If the integration is really bad, you can manually integrate it. Nitrogen and hydrogen are both detected, so it is difficult to compare. Let's focus on chromatography.

Molecular sieves can be used to separate O2 and N2, and TDX-01 can be used to separate CO2, CO, CH4, and N2. I think the chromatography method is simple, fast, and accurate.

Thanks a lot, but I still haven’t found the reason for the difference!