Your drift problem could be the lamp or the power supply, but here are
two more suggestions:
(1) Try swapping the flow cell with another 1100 at you location. If the
drift stops with the loaner installed, rebuild the flow cell. A misplaced
gasket can "flap in the wind" and cause some strange baseline problems. We
chased this problem in a new flow cell for a week.
(2) The 1100 series detectors are EXTREMELY sensitive to ambient light. Just
shine a flashlight at the flow cell and you'll get the point. Changes in room
lighting or simply walking up to the HPLC with a white shirt on can trigger
some strange baseline shifts. Two of our detectors are run with black garbage
bags draped over their fronts to eliminate the problem. Do leave the bottom
opening uncovered if you try this.
Good luck,
Steve
====================
Stephen Tindall
Argo BioAnalytica, Inc.
Phone: 1-973-605-2100
Fax: 1-973-605-2104
StvTindall@aol.com
====================
In a message dated 2/25/99 6:50:21 PM Eastern Standard Time,
halkidesc@UNCWIL.EDU writes:
Subj: HP-1100 diode array HPLC
Date: 2/25/99 6:50:21 PM Eastern Standard Time
From: halkidesc@UNCWIL.EDU (chris halkides)
Sender: abrf-request@aecom.yu.edu (Association of Biomolecular Resource
Facilities)
To: abrf@aecom.yu.edu (Recipients of ABRF List)
Hello Everyone,
We have an 1100 series hewlett-packard with a diode array detector.
We sometimes see slow (period of about 5 min) oscillations in the output.
The pattern is more complex than a simple sine wave. The amplitude is
about 2 milliabsorbance units both at 220 nm and at 280 nm. It is hard to
predict when the oscillations will appear or disappear. HP thinks it could
be the lamp and has suggested turning the flow to zero and seeing what
happens, but they don't have any further suggestions.
Does anyone have any ideas about what is going on, or useful ways
to proceed?
Chris Halkides
Christopher Halkides
Dept. of Chemistry, UNCW
601 S. College Road
Wilmington, NC 28403-3297
(910) 962-7427