Solvent Miscibility; Uv Cutoffs For Common Solvents - Waters ACQUITY UPC2 Overview And Maintenance Manual

Solvent miscibility

Liquid carbon dioxide functions as a nonpolar organic solvent much like
iso-octane or n-hexane. At conditions slightly above the critical point, liquid
carbon dioxide would possess a miscibility number of 28 or 29. As temperature
and pressure are increased on liquid carbon dioxide, its solvating power and
miscibility increase. This allows it to dissolve or mix with increasingly polar
compounds and solvents. Well into the supercritical region, supercritical
liquid carbon dioxide would exhibit miscibility properties similar to p-xylene,
toluene and benzene.

UV cutoffs for common solvents

The table below shows the UV cutoff (the wavelength at which the absorbance
of the solvent is equal to 1 AU) for some common chromatographic solvents.
Operating at a wavelength near or below the cutoff increases baseline noise
because of the absorbance of the solvent.
UV cutoff wavelengths for common chromatographic solvents:
Solvent
1-Nitropropane
2-Butoxyethanol
Acetone
Acetonitrile
Amyl alcohol
Amyl chloride
Benzene
Carbon disulfide
Carbon tetrachloride 265
Chloroform
Cyclohexane
Cyclopentane
Diethyl amine
Dioxane
UV cutoff
Solvent
(nm)
380 Ethylene glycol
220 Iso-octane
330 Isopropanol
190 Isopropyl chloride
210 Isopropyl ether
225 Methanol
280 Methyl acetate
380 Methyl ethyl ketone
Methyl isobutyl
ketone
245 Methylene chloride
200 n-Pentane
200 n-Propanol
275 n-Propyl chloride
215 Nitromethane
UV cutoff
(nm)
210
215
205
225
220
205
260
330
334
233
190
210
225
380
Solvent considerations 75