UV-Visible spectroscopy is one of the most widely used instrumental techniques in analytical chemistry, especially in the life sciences. As such, it is one of the most regulated, by pharmacopoeias and quality assurance bodies world-wide. Starna supplies the world’s widest range of Certified Reference Materials (CRMs) for the qualification of UV-Visible Spectrophotometers to help instrument users achieve compliance – with confidence. Ideally, references should be chosen whose calibrated values “bracket” the conditions to be used for analysis. While regulators like the Pharmacopoeias may recommend certain references, any Certified Reference Material with appropriate certified values may be used for qualification
Instrument Qualification Kits - Tools for Easier Compliance
These kits allow instrument qualification over the stated wavelength and absorbance ranges for compliance with EP 2.2.25 and USP. References are provided to qualify wavelength accuracy, absorbance accuracy and 3-point linearity, stray light and resolution/bandwidth.
Absorbance References
Potassium Dichromate (235-430 nm) - the most widely used reference for absorbance accuracy and linearity
Nicotinic Acid (210-260 nm) – recommended by Pharmacopoeias for absorbance accuracy and linearity in the far UV
Starna Green (250-650 nm) - Unique general-purpose reference for absorbance accuracy and linearity and wavelength accuracy in the UV and visible
Deep UV Reference (190-220 nm) – qualification in the deep UV: unique to Starna
Metal-on-Quartz Neutral Density Filters (250-635 nm) - durable filters with UV capability – now recommended by USP
Neutral Density Filters (440-635nm) - glass filters with absorbances from 0.04 A to 3.5 A
Combined Holmium/Neutral Density glass (360 - 640 nm)– 1 A absorbance check with wavelength calibration
Combined Didymium/Neutral Density glass (430 - 890 nm)– 1 A absorbance check with wavelength calibration
Wavelength References
Holmium Oxide Liquid (240-650 nm) - the most widely used reference for wavelength accuracy – cited by all major Pharmacopoeias
Cerium Oxide liquid (200-300 nm) - recommended by Pharmacopoeias for wavelength accuracy in the far UV.
Didymium Oxide Liquid (290-870 nm) – cited by the Pharmacopoeias and with useful peaks in the NIR
Combined Holmium/Didymium Oxide Liquid (240 to 795 nm) – evenly spaced peaks over a wide range
Combined Holmium/Neodymium Oxide Liquid (220 to 865 nm) – evenly spaced peaks over a wide range
Starna Green (250-650 nm) - Unique general-purpose reference for absorbance accuracy and linearity and wavelength accuracy in the UV and visible
Holmium Oxide Glass (270-640 nm) – more robust and useful for routine checks
Didymium Glass (430 - 890 nm) – more robust and useful for routine checks
Starna wide-range wavelength reference (335 - 1945 nm) -20 peaks from UV to NIR.
Combined Holmium/Neutral Density glass (360 - 640 nm) – wavelength calibration with 1 A absorbance check
Combined Didymium/Neutral Density glass – (430 - 890 nm) - wavelength calibration with 1 A absorbance check
Deep UV Reference (190-220 nm) – qualification in the deep UV: unique to Starna
Samarium Oxide Liquid (230 – 560 nm) – for the commonly used region from 200 nm to 500 nm
Stray Light (Stray Radiant Energy) References
Stray Light Cut-off Filters –Specified Wavelength Method – (175-385 nm) accepted by European and US Pharmacopoeias
Stray Light Cut-off Filters – Filter Ratio Method (175-385 nm) – recommended by US Pharmacopeia for measuring low stay light levels
Stray Light Glasses (220-440 nm) - convenient routine check for stray light
Resolution (Spectral Bandwidth) References
Toluene in Hexane (265 – 270 nm) - the most widely used resolution reference – accepted by all major Pharmacopoeias
Toluene in Methanol (265 – 270 nm) - resolution check for Derivative Spectroscopy.
Benzene vapour (230-270 nm) - resolution reference for instruments with spectral bandwidths less than 1 nm