Traces of detergent

Hi everyone!!!
How can one prove that after cleaning, no detergent residue is left in the glasswares.

Regards and Thanks.

I suggest you perform TOC (Total Organic Carbon) testing. This will tell you if there are any traces of detergent or product left.

TOC is a good option, but you need to know if the detergent used is detectable by TOC, you may have to use Conductivity or pH.

Thanks for the suggestions.
But does the TOC testing means: rinsing the cleaned glasswares with a purified water, and testing that water for TOC and again what should be the acceptance limits.

Yes, if you were going to use TOC to determine the detergent residue on your glassware, you would need to take a rinse sample using purified water, you would need to test the purified water by itself as a baseline and then test your sample. I would need a better description of your process and what you were using the glassware for to determine what your limit should be. Some people use the TOC limit for purified water. 500 ppb, as a starting acceptance limit. I would suggest as a starting limit, the TOC of the purified water that you use as a rinse, for example, if your Purified water gives you 50 ppb then the TOC of your rinse sample could not be above 50 ppb. But you should perform recovery studies on the detergent to determine if you can detect the detergent using TOC and your Limits of Detection and Quantitation.

Thanks to all for the valueable comments.
Warm Regards.

One Question. Are you checking the efficiency of a dishwasher? If so you can use a fluorescence dye to check cleanliness.