TOC Residual Detergent Cleaning Validation

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??:confused:


Nobody has ANY ideas on this?? Surely there must be someone else out there who has encountered this problem!?

Any help would be very much appreciated! Thanks

I would suggest that you stick to a detergent currently used in house. You will need to show that residue of cleaning products used on equipment within manufacturing processes can be detected by this method. Try checking with the manufacturer of the TOC analyzer you are using for validation suggestions for the cleaner/TOC analyzer. Another possibility is to perform TOC on the rinse fluid rather than on a swab. A direct correlation can be made between the TOC of the WFI/PW used for rinse and the “actual” rinse fluid sample. It may be much easier to “prove” this than the swabs.

Hello, (First of all, I am sorry for late response)

Numbers of factors will affect recovery studies such as [1] coupon spiking method, [2] swabbing method, [3] No. of swabs (we are using two swabs per coupon), [4] type of solvent (volatile/non-volatile), [5] swabs material, etc.

I developed an analytical method for cleaning validation last summer. I used sodium Lauryl Sulfate as a cleaning agent. For more information please check this video,

Let me know, if you need more help on this. I shall be glad to provide you with any further information:). I can be reached at or via phone at (001) 201-969-6220.

Best Regards,
Nikunj Vasoya