Electrochemical measurements using pH meters are now simple and accurate. Micro-electronic components have made possible small portable high quality instruments with digital displays, some with built-in electrodes. These meters measure the potential difference between a glass electrode and a standard calomel electrode or silver/silver chloride electrode and are calibrated by the use of prepared or purchased buffer solutions of accurately known pH. There are also available other types of electrodes designed for special purposes, such as probe electrodes for the examination of carcass meat. Very accurate pH measurement, through seldom required in food analysis, is very susceptible to the temperature of the test solution. Temperature compensation devices are incorporated in pH meters to correct for known temperature deviations.

Some of the pH values of a number of biological materials are given below:

Table A - pH Values of Representative Biological Materials, Elements of Food Biochemistry, William H. Peterson, Ph.D., John T. Skinner, Ph.D. and Frank M. Strong, Ph.D., pg 69

Water Treatment Testing: Food & Beverage

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