What Is a Portable pH Meter?
A portable pH meter is a pH meter that is specially designed to be carried. Basically, the measurement mechanism is no different from that of a stationary pH meter in a laboratory. The pH is measured using a glass electrode. The main body of the pH meter can be held in one hand, and unlike stationary pH meters, there is no stand to hold the electrode in place.
Uses of Portable PH Meters
The portable pH meters are designed to withstand field measurements, such as water quality measurements in the field, but can also be used in the laboratory, of course. They are robust and designed to withstand a wide range of usage conditions. It is waterproof, dustproof, and resistant to drop impact. They are often sold with a carrying case for easy transport. Ergonomically designed and small enough to fit in one hand, they can be used on production lines and in other practical settings.
Principle of Portable PH Meters
A pH is an indicator of hydrogen ion concentration. The glass electrode used to measure pH is made of a glass film that reacts to hydrogen ions. When this electrode is placed in a sample, an electromotive force corresponding to the hydrogen ion concentration is generated on the surface of the glass membrane. Theoretically, it is not possible to extract this electromotive force alone. Therefore, a voltmeter is placed between the reference electrode (comparison electrode) and the glass electrode, and this potential difference is displayed on the voltmeter. Before measuring a sample, the pH can be determined by measuring a liquid of known pH concentration (pH standard solution) and creating a calibration curve with the electromotive force. However, the relationship between pH and potential difference changes slightly with temperature. A temperature element is built into the electrode to compensate for changes in the electrode. Although a thermostatic bath can be used to equalize the temperature of the pH standard or sample, temperature compensation is an important feature for portable pH meters that are intended for field use. Temperature compensation is an important function for portable pH meters that are intended for use in the field.