Free chlorine has the highest disinfection efficacy and usually exists in water as hypochlorous acid (HOCl) or the hypochlorite ion (OCl – ), with the proportion of each dependent upon the pH of the sample.
Total chlorine is the sum of free chlorine and combined chlorine, or chloramines, which have weaker disinfection properties. When chlorine comes into contact with molecules containing nitrogen, it reacts to form a chloramine. Chloramines and free chlorine together are referred to as total chlorine.
Free chlorine and combined chlorine have different disinfection potential. Free chlorine has a stronger sanitizing potential and therefore the presence of free chlorine residual gives an indication of the sanitizing potential of your wash water. We recommend the level of free chlorine is set to ensure sufficient disinfection and must be monitored separately from total chlorine.
This is dependent on the application for which you are using the chlorine as a sanitizer. Other factors to consider include the organic matter, the type of produce, and the contact time. Levels can range from as low as 5 mg/L to over 200 mg/L.
There are numerous methods for measuring free and total chlorine. Our sensor technology provides precise and accurate results across a wide range of concentrations for free and total chlorine. Our sensor method has been designed specifically for food and beverage applications.
When chlorine interacts with natural organic matter in the water, disinfection by-products (DBP) called trihalomethanes (THM) are formed. These substances can have adverse health and environmental effects and need to be monitored.
Methods requiring dilution introduce potential error. For example, a 1 in 100 dilution magnifies any measurement error on the 1 mg/L by 100 times. For systems with high frequency of tests, and a variation in operator experience, errors are inevitable and magnified during dilution. Our sensor method has a high range, which reduces the need for dilution.
Kemio technology offers significant advantages compared to alternative techniques for sanitizer control in food and beverage. Unlike traditional methods, Kemio has no user subjectivity and minimal user input which minimizes potential operator errors and variation in results.