How is the validation of a method designed to detect residual detergents via TOC approached?
We have attempted to validate a method based on using Texwipe swabs and Deb TOT detergent (used widely on-site). However, although a good linearity from TOT solutions is achieved, we are unable to get repeatable recovery results i.e 39-103% range! Plus we use 5-6 different detergents/cleaning agents on-site.
We’re unsure whether these swabs retain the TOT detergent and if they are sufficent at all in consistantly recovering > 85%.
Does anybody know if the authorities would question validating a method based on a non-volatile detergent with a known organic carbon composition which is not used on-site? Or based on a protein or caffeine perhaps just to show the method can be used at low ppb levels and then apply the method to the detection of residual detergents?
Also how do you approach determining a general detergent TOC limit for residual detergent cleaning validation??