Free chlorine testing
When processing fresh-cut produce disinfection is often carried out by adding free chlorine, in the form of hypochlorite at concentrations greater than 50 mg/l, to the wash water in a process known as superchlorination.
While there is no one perfect method to specifically measure free chlorine at superchlorination levels Palintest offers a number of options for users aiming for superchlorination, including the ChloroSense method, the Iodometric Colorimetric method and the DPD Colorimetric method. Which one is used will depend on local circumstances and requirements.
ChloroSense method
ChloroSense uses an electrochemical technique called chronoamperometry and includes an instrument and a disposable pre-calibrated sensor, allowing non-technical users to rapidly obtain accurate results. Although the device provides a free chlorine reading (up to 10 mg/l), operators can use the total chlorine reading (up to 100 mg/l) to demonstrate superchlorination has been achieved. Additionally, ChloroSense® is glass- and reagent-free and ensures traceability with integrated data logging, making it ideal for use in high-care and GMP environments.
Iodometric Colorimetric method
Another method for determining total chlorine can be carried out using Palintest’s Chlorometer Duo. This is a colorimetric version of a standard method allowing total chlorine readings up to 250 mg/l – again demonstrating superchlorination has been achieved.
DPD Colorimetric method
The DPD method is also available on Palintest’s Chlorometer Duo and has been the standard method for determining free and total chlorine in water for over fifty years. However, it has a limited test range (0 – 5 mg/l), meaning dilution on the production line is required.
In most applications where water is expected to be maintained at superchlorination levels, the ChloroSense or the Chlorometer Duo are proven and straightforward approaches to demonstrating effective disinfection is taking place.
