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- Posts: 16
- Joined: Mon Jan 17, 2011 12:19 am
I am new to CE and am trying to setup an Agilent CE using DAD detector. All the parts are working well and I have no trouble connecting to the software and controlling the set points and samples vials etc. I have set up my method for detection of Anions using the Agilent method notes. I have a nice baseline on the DAD detector but I am not getting any peaks for the Anions. I'm confident the machine is working as the DAD passes the calibration and all the lifts etc work fine. The install time of the bulb is over the recommended time limit but I have no idea if the last user reset it when the bulb was installed. I think it's a good one though. I have a couple of questions about the capillary etc....
1. What are some common causes of flat baseline (when DAD lamp/system appears to be working)?
2. Why is the polyimide removed from ends of capillary column? And do I need to trim the column ends or leave them as they are out of the box? (I'm using an uncoated fused silica column (a tiny bit shorter than the method notes mention but I think it should only elute the analytes a bit faster...) and have conditioned it with 1N NaOH (how do you determine there is flow through the column?)
3. According to the method notes I am running a negative 30kv setting and the setpoints do achieve this but my uA is -12.1 and there are -0.4watts... please let me know if the uA or Watts may be off what you would expect to see. I have tried both inlet and outlet loading of sample with no luck.
4. I am currently not using the regeneration options but am loading the proper buffers, samples, and waste vials where they belong. The buffer is a bit old - could this be the issue? The Anion sample is new.
5. I have tried both Pressure sample loading and Electrical sample loading with no luck. I'm using the internal pressure pump and not the external. Any thoughts?
6. The DAD is set to the recommended settings and the software reads back as though all is well...I believe my column is installed correctly with the clear etched part lined up in the detection cell and both ends are clearly under the sample/solvent level in both inlet and outlet vials.
Thanks for your help in advance!