How to choose the right pH meter?

What is a pH meter?

pH, the Latin abbreviation for Pondus hydrogenii, is a standard used to measure the activity of hydrogen ions in substances. This concept was first proposed by biologist Zelenson in 1909. Its mathematical definition is the negative of the logarithm of the hydrogen ion concentration, i.e. pH=-logCH+. The pH meter, as an electrochemical analysis instrument, is a device specifically used to measure the pH value of aqueous solutions. It is mainly composed of two parts: an electric meter and an electrode. The electric meter part includes key components such as an impedance converter, amplifier, positioning adjuster, slope adjuster, temperature compensator and display; while the measuring electrode is usually composed of an indicator electrode and a reference electrode. Consisting of, the indicator electrode of the composite electrode is often made of glass, and the reference electrode is called the internal reference electrode. pH meters are widely used in many fields such as industry, electricity, agriculture, medicine, food, scientific research and environmental protection. It is also an essential inspection instrument for companies to conduct QS and HACCP certification.

Types and choices of pH meters

Depending on different applications, pH meters can be divided into various types such as pen pH meters, portable pH meters, laboratory pH meters, and industrial pH meters.

Classification according to application occasions

1. Pen-type pH meter, this type of pH meter is mainly used to replace traditional pH paper, and is characterized by easy use and relatively low accuracy.

2. Portable pH meters. These pH meters are suitable for on-site and field measurements and require high measurement accuracy and comprehensive functions.

3. Laboratory pH meter, which is a high-precision desktop analytical instrument designed to provide high-precision measurements in a laboratory environment, while also having advanced functions such as printout and data processing.

4. Industrial pH meters are specially designed for continuous measurement of industrial processes. They not only need to have measurement and display functions, but also need to consider various factors such as alarm, control, installation, cleaning and anti-interference.

Classification based on instrument accuracy

The accuracy of a pH meter is an important indicator, which determines the accuracy of the measurement results. According to this indicator, the pH meter can be divided into several levels such as 0.2, 0.1, 0.01 and 0.001. The smaller the number, the higher the accuracy.

When selecting a pH electrode, it is necessary to make reasonable configuration based on the measurement samples. The performance and selection of pH electrodes are critical to pH measurement results. Improper electrode selection may lead to problems such as increased errors and unstable readings, which may affect the normal use of the instrument. Many customers can get normal results in standard solutions, but the problem of not obtaining accurate and stable results in reagent samples is often caused by improper selection of pH electrodes.

Ideal for pH testing of trace solutions

The semi-micro pH composite electrode specially designed for micro containers such as test tubes and centrifuge tubes is made of glass material, which is simple and practical, and meets various micro pH testing needs.