The determination methods of laboratory ozone meters mainly include ultraviolet absorption method, electrochemical method, iodometric method, colorimetric method, and detection tube method. Among them, ultraviolet absorption method and electrochemical method have become mainstream technologies in laboratory and environmental monitoring due to their high sensitivity and good stability. The following are specific measurement methods and principles:
UV absorption method
Principle: Ozone has the maximum absorption coefficient for ultraviolet light with a wavelength of 253.7nm. When ultraviolet rays pass through the ozone layer, their intensity will decay, and the degree of decay is proportional to the concentration of ozone, in accordance with Lambert Beer's law. By measuring the changes in light intensity before and after ultraviolet radiation passes through ozone, the concentration of ozone can be calculated.
Features: High detection accuracy, good stability, and minimal interference from other oxidants. But the equipment cost is high, suitable for laboratory environments that require high measurement accuracy.
Application: It has been adopted as the standard method for measuring ozone in ambient air by countries such as China and the United States, and is widely used for detecting the concentration of dissolved ozone in gases and water.
electrochemical method
Principle: Ozone undergoes an oxidation-reduction reaction with electrode materials, producing an electrical signal proportional to the concentration of ozone. By measuring this electrical signal, the ozone concentration can be calculated.
Features: Fast response speed, high sensitivity, and relatively low equipment cost. Suitable for measuring low concentration ozone, such as laboratory environmental monitoring, industrial process control, etc.
Application: Electrochemical ozone detectors are commonly used in laboratories for real-time monitoring of ozone concentration, providing accurate data support for experiments.
Iodometric method
Principle: Ozone acts as a strong oxidant and reacts with potassium iodide aqueous solution to generate free iodine, while ozone is reduced to oxygen. The concentration of ozone can be calculated by titrating the amount of free iodine.
Features: Easy to operate, low cost, but relatively low measurement accuracy. Suitable for occasions that do not require high measurement accuracy, such as teaching experiments, preliminary screening, etc.
Application: The iodometric method is one of the standard methods for determining gas ozone in China and many countries, but it is less commonly used in high-precision laboratory measurements.
colorimetry
Principle: Determine ozone concentration based on the degree of color or decolorization reaction between ozone and different chemical reagents. According to colorimetric methods, it can be divided into artificial color sample colorimetry and photometer colorimetry.
Features: Easy to operate, low cost, but measurement accuracy is greatly affected by human factors. Suitable for detecting the concentration of dissolved ozone in water, such as controlling the amount of ozone added during water treatment processes.
Application: The colorimetric method is commonly used in the laboratory for rapid detection of ozone concentration in water samples, providing preliminary data support for experiments.
Detection tube method
Principle: The ozone oxidation variable reagent is impregnated onto a carrier and packaged as a reactant in a standard inner diameter glass tube to make a measuring tube. When in use, cut off both ends of the detection tube and connect the air extractor to the exhaust end of the detection tube to extract a certain amount of ozone gas. The ozone concentration is directly proportional to the color change length of the reagent column inside the detection tube, and the concentration value is read through the scale value.
Features: Easy to operate, fast and intuitive, but measurement accuracy is greatly affected by factors such as the quality of the detection tube and environmental temperature. Suitable for rapid on-site detection of ozone concentration, such as environmental monitoring, industrial safety, etc.
Application: The detection tube method is commonly used in laboratories for preliminary screening or rapid on-site detection of ozone concentration, providing fast data support for experiments.