I have an Agilent model 6890 GC with an Agilent model 7694 Headspace Sampler. THe GC is controlled by Waters Millennium software, which also provides data collection and processing. Ocasionally there is a pressure drop in the auxiliary valve which supplies Helium to the headspace sampler. This shuts down data collection by Millennium. Any suggestions ??
By Anonymous on Thursday, March 27, 2003 - 07:02 pm:
It would be easier to identify this problem if you had an Agilent ChemStation instead.This seems to be only a coincidence (pressure drop x data collection?!).I would check cables or the software itself.
By ves on Wednesday, July 30, 2003 - 07:25 am:
You are proably only acquiring the signal from the gc. The gc is telling the headspace autosampler when it can flush the contents in the sample loop to the head of the gc column. The millenium software is acquiring the voltage output from the gc signal. The gc must be issuing some kind of message that interrupts the voltage output being sent to the software package. Might it be possible to delay acquisition on the part of the millenium software until after this event takes place? I do recall there are event controllers in millenium.
Also, does your gc have electronic pressure control? If so, you might want to switch that off.
By Hugh on Wednesday, July 30, 2003 - 11:17 pm:
How do you have the headspace plumbed to the GC? Are you splitting the gas flow between the 6890 and the 7694? If this is a 6890, I assume that it has an EPC valve. Are you splitting before or after the EPC?
By Hai Thanh Le on Sunday, February 22, 2004 - 11:47 pm:
I have the same situation sometimes. You may look at the split ratio of the capillary column. It may be too low.