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An ORP standard is not specified by its millivolt value alone. Before ordering online, check which reference electrode your meter uses, the temperature of the check and the manufacturer’s verification procedure.
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.
ORP measures a potential, not a concentration
Oxidation-reduction potential describes an electrochemical potential. It is not a direct concentration reading for a particular disinfectant or contaminant. A successful standard check therefore does not prove that a process-water concentration is correct.
Identify the reference electrode
An ORP value is reported relative to a reference electrode. Different reference systems can produce different expected readings for the same solution. Include the probe model and reference specification, not just the handheld meter’s name.
YSI’s ORP measurement guidance highlights the importance of the reference system and measurement conditions. Use your instrument’s procedure to establish the expected result.
Account for temperature
The expected potential of a standard can change with temperature. Check the solution documentation and record the actual temperature of the verification. Do not assume that a value stated at one temperature is the correct target at every other temperature.
For example, YSI’s Zobell solution information provides temperature-dependent reference information. The applicable values must match the actual standard and electrode combination.
Separate verification from adjustment
Some instruments support an offset adjustment; others use a standard only to verify performance. Follow the approved instructions for your model. Cleaning, stabilisation and electrode condition can affect a check, and changing an offset is not a substitute for diagnosing a deteriorating probe.
What to send when ordering ORP standards online
Specify the instrument and probe, reference electrode, required solution specification, temperature conditions, volume and quantity. Ask for the batch information and documentation your quality system needs. Start through our ORP standards page, where suitable or bespoke requirements can be discussed.
Does a correct standard reading validate every process measurement?
No. It supports the defined instrument check. Process measurements still depend on sample conditions, electrode suitability and the site’s approved method. Keep the verification record alongside maintenance and process records so changes can be investigated.
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Need help with ORP standards?
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.
