Chromatography Forum

Hi There people i am experiencing problem with the Dionex LC25 Chromatography . When i load and inject the samples through an autosampler the chromeleon software main panel shows the peaks, but wait a minute these are continuous peaks, i mean i dont get a baseline at all. I think the computer is not connecting to the LC system eventhough it shows connected at the main panel.Please guys help me out Thanks.

if you always get the same picture regardless of what you inject then it is possible that you system is half configured as a demo. overlay the chromatogram ad check the areas of peaks from injection to injection if it is the same.

check your server configuration first to see if your detector is correctly configured. maybe it was switched to demo mode.

if you do not get the same picture each time then you probaly have a real problem with your system.

Dear Imran:
I hope that you will not be offended with some basic questions.
1. Did you use the system before? Did it work for you before?
2. Are you trying to develop a new method?

If you never use CM before, get ready for a steep learning curve.
In CM, you have several channels monitored in one run (injection): UV abs, pump pressure, oven temp. You may need to navigate among channels (perhaps you were looking at the trace of the pump pressure?)

Try to get help from a veteran, if possible. Or else, contact Dionex for tech support. Good luck.

Alfred.

Dear Alfred,

Here are the answers to your questions.

1. I was newly recruited as a lab technician and i had to focus on repairing LC from the scratch from day one. The system was not working before i came but it is showing signs of life now. They say it used to work before but, then had some problem and it stopped working.

2. The system is as good as old and have methods already stored in the system so, iam not making one.

Anyways, If you could help me i'll be thankful.
Regards
Imran

Dear Imran:
I just give you some tips to get started. Your upper management should "empowered" you with more knowlege and training.

Click on the "Browser" button (under the View menu).
-> Navigate to your recent acquired sequences. Open the sequence, and click on a single run.
-> -> Click QNT-Editor button
-> -> -> In the Peak Table, check the setting of the Retention time.
-> -> -> -> Navigate among different channels of detection. Use the 2 buttons, or else just click F10; or Shift +F10.
Also, Navigate among different samples of the same sequence: Use the 2 buttons, or else just click F4; or Shift +F4.

Note: The run time must be sufficient for the peak to elute. To start, you may set it at 30 minutes.

Also, you may check the following basic things:
Column correct?
Mobile phase correct?
Wavelength correct?
Injection volume correct?
Sample prep correct?
Oven temp correct?

Alfred

Imran

also try to find the tutorial file on your PC.
there is either a shortcut on your desktop, or you can go to Start>programs> chromeleon> tutorials.