Chromatography column separation efficiency
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There is no component A produced using Machine No. 1, but component A with a concentration of 0.7% is produced using Machine No. 2. I would like to ask you all what causes this? Please help analyze this. The carrier gas is stable, and the injection pad has no leaks. Pillar 1 and Pillar 2 are the same. Thank you!
Assumption: 1 is FID ； Number 2 is TCD ； Conclusion: The instrument is wrong! May I give a suggestion? There are many variables; even for the same instrument, different parameters lead to different results…… ； I just hope that the more specific the description, the greater the chance of reaching a conclusion. Generally speaking, I don’t think your questions are related to applications; they’re more like chromatography-related quiz questions. Personal opinion.
Thank you to the friend on floor 2 for their suggestion. I am just starting out with analysis and am an amateur; please forgive my ignorance. I can’t identify any problems at the moment, and there’s no one I can turn to for help, so I’m asking the teacher from Haichuan for assistance.
It’s okay! I could only see a misty landscape; it was a bit hard to understand. I’m a beginner too. What I mean is that, to solve a problem, one must learn to ask questions and identify the issues; the clearer and more comprehensive this is, the better. Otherwise, giving one-sided answers can lead to problems. Also, in chromatography, the spectra are very important; including some spectra and then asking questions will yield better results.
Let’s get back to the topic: this falls under constant analysis. Have you tried testing the two instruments with standards, and then conducting a minimum detection limit test for the two chromatographs using dilution? By doing this, you will obtain a complete set of data. If you want to take the easy way out, age Column 1 first and then conduct the same qualitative and quantitative tests to see. The columns are severely polluted. They can’t even achieve 0.7%. It would be great if the detector type, column number, sample, and instrument parameters could be specified clearly! You should know that temperature, pressure, flow rate, injection volume, the column, and the detector – every aspect of a process has an impact. That’s all for now. Try it first.
I mean, the questions asked are rather confusing. # You must be using chromatographic analysis, right? Be more specific – for example, what is the carrier gas used in the two instruments, what is the flow rate of that carrier gas, and what are the temperatures of the detector, vaporization chamber, column, etc.? Clearly state the issues so that others can help you solve them! Also, check if the columns are contaminated
If the injection pad doesn’t leak, then check whether there are any leaks at the connections at both ends of the column…… and also check if there are any leaks at the connections for the carrier gas. If not, it might be a problem with the sensitivity of the detector…… You can go to a bookstore or borrow books on instrumental analysis from colleagues; they contain information on this.
The book should have it on the page; I’m a bit unused to the restrictions on attachments on pages. Just take a look at the gas phase section of the chromatography series.
1. If the chromatography conditions of the two instruments are exactly the same (temperature settings, column specifications, split ratio, injection volume, detector type, pressure conditions, etc.), and both instruments are able to generate signals properly, then the situation you described cannot occur. If it does occur, there is only one possible explanation: a difference in detector sensitivity, with one detector being more sensitive and the other less so. 2. If the chromatographic conditions of the two machines are not exactly identical, such as different detector types or column types, it is possible that this component will not appear as a separate peak or will merge with other peaks.
It might be due to temperature and pressure; the injection conditions also have an impact
The operating conditions for the two gas chromatographs are the same; they both use packed columns. The substance we tested has a low boiling point, around 70 degrees. Moreover, for this chromatograph that does not show peaks, the peaks that do appear are very wide; even when the attenuation is set to its minimum, the peaks remain wide. There’s an issue with sensitivity; are there any good ways to solve it?
I hope to share with everyone the detailed information such as analysis parameters and instrument hardware configuration, Instrument Advisor. In my opinion, one possible cause for this situation is a difference in the sensitivity of the detectors, or a difference in the efficiency of the chromatography columns.
This situation may be due to poor separation of the chromatographic peaks. The peak of Component A is obscured by other peaks, so it is not visible. The solution to this problem is to age the chromatography column. After aging, try again once the baseline stabilizes; if it still doesn’t work, the issue is likely a damaged chromatography column.
Since the peak is wide, consider the issue of the injection volume. Is it too big?
I’m asking out of curiosity: are you the moderator of the Instrument Subnet, chengjingbao? Hehe, what a friendly name
You’re too modest! If you search for your name online, you’ll find a ton of results. Very famous.
Thank you to the two people above; it’s me. I hope working there will satisfy you both. Let’s focus on the matter at hand; it’s important for everyone to learn together and help one another. Welcome to the analysis section of the Chemical Engineering Forum. This post was last edited by chengjingbao on 2009-2-20 19:58.]
Try choosing Machine A with a programmed temperature increase; if, based on what you’ve said, the conditions are exactly the same and no difference can be detected, then it’s likely that the column efficiency of Machine A is poor