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Baseline noise at Less than 220nm
Posted: Mon Aug 08, 2011 2:00 pm
by roslin
My baseline noise in hplc is very high at wavelength less than 220nm only . I am using mobile phase methanol/water 3:2
how do i resolve my problem?
Re: Baseline noise at Less than 220nm
Posted: Mon Aug 08, 2011 2:46 pm
by tom jupille
How high is "very high" (what is your peak-to-peak noise measured in absorbance units)?
Are you pre-mixing your mobile phase or mixing in-line using the pump's proportioning system?
Is the noise periodic or random?
Possibilities include:
- dirty or contaminated methanol
- a dirty flow cell
- irregular pump flow
- dirty or contaminated water
- a dying lamp
- mixing problems
Re: Baseline noise at Less than 220nm
Posted: Mon Aug 08, 2011 7:22 pm
by skunked_once
Pure methanol has a significant UV absorbance at 220 nm and the absorbance increases quickly below 220 which would result in a very high background signal.