What sterilisation leaves behind
Radiation sterilisation, and to a lesser extent heat, can create radicals in a material. They can go on reacting after the treatment, degrade the material and reduce the potency or the properties of a product. EPR counts these radicals directly, so the effect of a sterilisation can be measured, and the effect of an antioxidant or a different dose or process can be compared.
Where it is used
- Active ingredients and excipients
- Polymers, packaging and device materials
- Medical devices and components
- Raw materials checked for trace metals
Typical tasks are measuring the radicals that remain after gamma, electron-beam or heat treatment, following how fast they decay, comparing materials or antioxidants, and checking raw materials for traces of paramagnetic metals.
Radicals and metal ions have their own spectra
A radical shows up as a spectrum whose size is its amount and whose shape tells what it is. Paramagnetic metal ions such as copper(II), manganese(II) and iron(III) show up as characteristic patterns. Comparing the samples with a reference of known spin number gives quantities.
What it adds
- Sees radicals and paramagnetic metals directly and selectively
- Detects traces in the presence of everything else in the sample
- Non-destructive, with little preparation
- Compares sterilisation methods, doses and protective additives on the same scale
Points that matter in practice
- Radicals decay with time, so measure soon after the treatment and again later, and record the storage conditions in between
- Only paramagnetic states give a signal. A metal in a diamagnetic state, such as copper(I), is not seen, so a missing signal does not prove that the metal is absent
- The amount that can be detected depends on the sample, and it should be established for your own material
- Quantification needs a reference sample and identical measurement conditions
- The link between the radical level and product performance has to be established for your own product
From your question to a routine method
Send or bring representative samples. MSY Consulting runs feasibility measurements, helps you plan the timing and the reference, and trains your team until the measurement is part of your routine.
Let's talk about your application
Send an email describing your instrument and your application, and you will get a reply.
contact@msyconsulting.euMSY CONSULTING SAS · Wissembourg, France · LinkedIn