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Ordering a UV254 or UVT standard starts with the analyser specification, not just a number on a bottle. The measurement type, optical path length and verification procedure determine whether a solution is suitable for your instrument.
Online Reagents is backed by PMA’s chemical-manufacturing experience of more than 52 years. Send your specification online to discuss suitable supply, availability and quantity before confirming an order.
Absorbance and transmission are different measurements
UV254 absorbance describes how much ultraviolet light a sample absorbs at 254 nm. UV transmission, usually written as UVT, describes the proportion passing through it. Hach’s UV measurement guide explains their logarithmic relationship. They are not interchangeable labels for the same numerical result.
Check the optical path length
An absorbance or transmission value needs a stated path length. A solution measured in one cell length will not necessarily produce the same value in another. Supply the instrument model, wavelength and path length shown in its manual, and say whether it reports a measured or normalised value.
If you are unsure, send the relevant manual page with your enquiry. Avoid choosing a nominal UVT percentage without identifying the conditions to which that percentage applies.
Specify what the check is intended to prove
A standard can support an instrument check under a defined procedure. It does not automatically establish a universal relationship between UV254 and dissolved organic carbon. Such relationships depend on the water and the method.
Tell us whether you need a routine verification solution, a calibration material or a particular test point. Request the stated value, conditions and supporting documentation required by your quality system.
What to include in your online enquiry
Provide the analyser make and model, measurement type, required value, path length, bottle size and quantity. Include the existing solution specification or part number where available. The UV254 and UVT standards page is the starting point for discussing suitable supply.
Keep verification records useful
Record the solution identity, batch, expiry date, temperature where relevant, instrument settings and result. Use acceptance criteria from the approved instrument procedure rather than inventing a tolerance from the bottle value. Investigate a failed check before changing calibration settings.
Can I order without knowing the path length?
You can start an enquiry without it, but suitability should be confirmed before ordering. Send the model and available documentation so the missing detail can be resolved. That short check helps prevent purchasing a standard with an unsuitable specification.
Ready to discuss UV254 and UVT? Share the analyser details and required specification so our team can help check the next step.
Need help with UV254 and UVT?
Contact our team about this article or your reagent requirement. Include the analyser make and model, method, range and quantity so we can respond to the right specification.
