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Units of UV abs. peak area in masslynx
Posted: Tue Mar 30, 2010 4:52 pm
by grumbledook
Does anyone know the unit which masslynx reports for UV absorbance peak areas? With Chemstation (mAU*s) and Chromeleon (mAU*min) I am able to calculate back the amount of injected protein using the molar absorption coefficient of the protein (taking into account flow rate and path length of the flow cell). This doesn't work with MassLynx. (Neither mAU*s nor mAU*min seem to be the actual unit of the reported peak area.) Is "mAU" from MassLynx really "m absorbance units" or more like "m arbitrary units"? (Sample recovery is not the problem here.)
Posted: Mon Apr 12, 2010 4:46 pm
by grumbledook
Whoever is interested in:
Using Waters TUV detector in dual wavelength mode may lead to deviation
in IPA's for either WL compared to single WL mode. We observed ~15 % smaller IPA at 214 nm in dual wavelength mode. Values measured in single WL mode correspond to the ones expected from Beer-Lambert's law. (Recalibration of the detector doesn't change the situation.)
Mass calculations. (WAS: Units of UV abs. peak area in massl
Posted: Thu Jun 30, 2011 12:06 pm
by mspittel
Does anyone know the unit which masslynx reports for UV absorbance peak areas? With Chemstation (mAU*s) and Chromeleon (mAU*min) I am able to calculate back the amount of injected protein using the molar absorption coefficient of the protein (taking into account flow rate and path length of the flow cell). This doesn't work with MassLynx. (Neither mAU*s nor mAU*min seem to be the actual unit of the reported peak area.) Is "mAU" from MassLynx really "m absorbance units" or more like "m arbitrary units"? (Sample recovery is not the problem here.)
Could you please give me an example of calculation on how to derive the mass of injected protein from the mAU*s peak area, molar absorption coefficient, path length and flow rate? I do have exactly this problem because there are no certified standards for my analyte so I can't use a calibration curve and I'm not quite sure I got right the calculations.
Thank you in advance.