Toluene in Hexane (265 – 270 nm)
A solution of toluene in hexane is the most widely used reference for qualifying the Spectral Bandwidth (SBW) of a UV spectrophotometer. It is accepted for this purpose by most Pharmacopoeias and Standardisation Bodies, including:
Deutsches Arzneibuch (German Pharmacopoeia).
United States Pharmacopoeia
American Society for Testing and Materials
Therapeutic Goods Administration (Australia)
It can be used with spectrophotometers having spectral bandwidths of 3 nm or less.
Toluene In Methanol (265 – 270 nm)
This reference is described in the European Pharmacopoeia (EP) for Use as a resolution check in Derivative Spectroscopy.
Benzene Vapour (230-270 nm)
This reference is useful as a resolution check for instruments with spectral bandwidths less than 1 nm. Benzene vapour has characteristic peaks that may or may not be displayed, dependent upon the actual SBW of the instrument.
Note: Benzene vapour is not suitable for use with photodiode array spectrophotometers.