I'm running an HP 6890 with an NPD detector. The injection solvent is methylene chloride. This causes a deterioration of the signal over time that can't be corrected by jacking up the bead current. A new collector funnel usually solves the problem. Two questions:
1) does anyone know how to get around the arbitrary upper limit of 4.095 on the bead current?
2) does anyone know a simple way of reconditioning the collector funnel?
By Anonymous on Wednesday, July 12, 2000 - 11:19 am:
The answers are:
1) The current limitation is not arbitraty, but is set so that the detector is not damaged by overheating of the bead. Don't try to over-ride the limit unless you are prepared for a large repair charge.
2) Replacement is the best solution. The compounds used are very toxic, and most labs are not set up for safe handling of them.
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