Appendix 1
pH electrodes
Before Use
Remove the protective cap covering the glass sensing bulb and
replace with the protective guard if applicable. Inspect the filling
solution for air bubbles and remove by shaking in a downward di
rection. Soak the elech·ode in pH storage solution for 30 minutes.
Cleaning
Soak the electrode in 0.IM HCl for 15 minutes followed by soak
ing in pH storage solution for 30 minutes
Storage.
Put some pH storage solution in the protective cap and place over
the glass bulb.
Never store the elech·ode in distilled or de-ionised water. Never
allow the elech·ode to dry out.
pH electrode storage solution is made up by dissolving lg KC! in
I 00mL of pH 7 buffer
pH Buffers
Buffer Capsules
Buffer capsules are made up as follows For each buffer, empty the
powder into a suitable container. Using deionised water, make up
to 1 00mL ensuring that the powder is filly dissolved before use.
The coloured outer skin may be added to colour code the resulting
buffer. This may take up to 4 hours to dissolve but will not affect
the pH of the buffer.
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