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Stabilizing pH of liquid laundry detergents
quantumnoodle:
--- Quote from: AWK on December 01, 2020, 08:27:56 AM ---You have at least 3 substances that influence the pH of the mixture significantly and without knowing all the concentrations it is difficult to advise anything.
Besides, the Forum does not provide advice to producers remotely. Contact an on-site chemist.
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Hi, thank you for pointing this out. I'd consider these on my next experimentation.
quantumnoodle:
--- Quote from: Corribus on December 02, 2020, 02:16:29 PM ---I have not much advice on this problem generally, but I will add that I would not consider a drop from 9.2 to 8.9 to be "drastic". Whether this small drop is significant depends a lot on how you are measuring the pH, how good your standards are, what standards you are using, how well your meter is calibrated and the range it is calibrated over, etc. My suggestion would first be to ensure your analysis of pH is up to snuff before you worry about the effect of your formulation, especially since this is your "first time handling this task". Validation of your method would be a first step in any real R&D laboratory, and measuring pH accurately and precisely isn't as easy as people think it is - particularly in complex mixtures with very high ionic strength.
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Hi, I haven't much thought about this but, our work instructions suggest to measure liq det samples 'as is' (no dilution, however, some study suggest to measure pH of liq det at 1% solution) using a calibrated pH meter. I will consider your suggestion and will take a look into our method and may be conduct a re-validation. Thank you for the help, much appreciated.
Corribus:
For that matter, you will want to make sure you are using the right pH meter for the intended purpose. Liquid detergents are usually pretty viscous, and no every probe is suitable for measurement in viscous solutions, see, e.g.,
https://www.coleparmer.com/blog/2013/01/31/measuring-ph-in-viscous-samples-too-hard-to-handle/
Also note that diluting your solution will also affect your pH reading.
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