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Fwd.: pH Electrodes & acid cleaning from an APD lurker

Fwd. from a personal note.

> Citex wrote:

> Just thought I'd mail you the standard lab procedure we use for cleaning
> electrode membranes.
> The glass membrane on most probes can be cleaned by a 30 min soak in 0.1 M
> HCl or nitric acid - HCl is much less corrosive to skin etc,
> concentratedHCl is ~37% which is ~11.7 M. Follow this with at least 1 hour
> in pH 7.0 standard or "storage solution" - most commonly saturated KCl. If
> you can change the filling solution on your electrode, do this after the
> soak.
> Don't use base (NaOH) solutions since these etch the glass membrane
> (except if you're gonna toss it anyway, then try a 10 min X 0.1 M NaOH).
> If you can get some EDTA (Ethylene Diamine Tetra Acetic Acid, tetra sodium
> salt ie the right pH for the job) do this for 15 min to remove organics &
> greases Then do the 1 hour soak as above.
> Send this to the list if appropriate.
> Regards
> Karen Rupitz

It was, IMHO, so I shall. Thanks.


Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot com

                There are two rules for success in life:
             Rule 1: Don't tell people everything you know.

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