Happy new year 2011!
I am actually developping an analytical method (TOC) for cleaning validation.
Our acceptance criterion is very low ~0.2ug/cm^2 (is it really low?).
Our solvent for cleaning and doing the analysis is NaOH 2%. The analytical method used is TOC. We have to acidify the sample in NaOH 2% until pH 2 to permit analysis in TOC (persulfate+UV+Heat system).
We have a lot of problem to get stable analytical blank (NaOH 2%+acid). Absolute signal varies on each test that we do and is not small (sometimes bigger than signal of Sucrose standards solutions made of the same solvent +acid).
Low carbon Swabs are not stable in NaOH (acid add create sometimes snow in our vials ) and gives more contamination.
In this way, analytical contamination is impossible to manage.
Did anyone already had these problems? What others problems did you have?
How do you manage to work with NaOH in TOC analysis for cleaning validation?
ideas are welcome!
PS: My english is bad, but my problems are real^^