1. Prepare the test material according to requirements in the monograph or according to specific procedures. If the pH of
the test sample is sensitive to ambient carbon dioxide, then use Purified Water that has been recently boiled, and subsequently
stored in a container designed to minimize ingress of carbon dioxide.
2. Rinse the pH sensor with water, then with a few portions of the test material.
3. Immerse the pH sensor into the test material and read the pH value and temperature.
In all pH measurements, allow sufficient time for stabilization of the temperature and pH measurement.
Diagnostic functions such as glass or reference electrode resistance measurement may be available to determine equipment
deficiencies. Refer to electrode supplier for diagnostic tools to assure proper electrode function.
Where approximate pH values suffice, indicators and test papers (see Indicators and Indicator Test Papers, in the section Reagents,
Indicators, and Solutions) may be suitable.
For a discussion of buffers, and for the composition of standard buffer solutions called for in compendial tests and assays, see
Buffer Solutions in the section Solutions. This referenced section is not intended to replace the use of the pH calibration buffers
in Table 2.