Hypochlorite residue

Hi all,

We have to change our current biocide and we start to use hypochlorite, so we have to demostrate that we can eliminate the residue that it could left. Would it be enough testing the ph of the wáter rinse or we had to test conductivity too? Is it neccesary to make a calibration curve for conductivity to quantify the residue or would it be enough if we assume the WFI conductivity criteria in rinse water?

Thank you very much in advance!

Have a nice day!

I had to deal with the same problem, since we change the concentration of hypochlorite in our sanitization procedures (from 0.025 to 0.05%). We used a colorimeter (from LANGE) with a kit for Cl2 quantitation to analyze the rinsing coming from the equipment, after sanitization. We calculated the limit considering the DL50 of hypochlorite and the surface of each machineries. It was the easiest way to quantify Chloride we found (avoiding using conductimeter and making a cal. curve).


Thank you very much Marcopaolillo! Could you please clarify me if the use of that instrument for conductivity is accepted by FDA? I don’t know if you have to do the same assay for WFI conductivity that USP requires although this is rinse water… What do you thik? Thanks in advance again!

You can use the limit test for chloride or titrate using silver nitrate. (Mohr titration). You also need to show that there is no chlorine.