Why does my baseline rise with acetonitrile and water gradient with 10mM ammonium dihydrogen phosphate in water at 210-nm UV wavelength but not as much in the presence of methanol? - WKB107521
Article number: 107521
ENVIRONMENT
- Chromatography
- UV detector
ANSWER
The UV cutoff of methanol is 205 nm, water is approximately 200 nm, and the buffer is 210 nm. The UV absorbances for the three components are close and are better able to cancel each other out in what the detector interprets. However, with acetonitrile, the UV cutoff is 190 nm. This is enough of a UV wavelength differential to pick up a response or raise the baseline.
ADDITIONAL INFORMATION
For additional information, see the Wilson, Morrison, and Dolan LC/GC article 2001 at https://www.chromatographyonline.com/view/buffers-and-baselines.
id107521,