What are the different types of chlorine analyzers and their applications?

Chlorine analyzer types: Amperometric (electrochemical cell measures current from chlorine reduction - free or total chlorine, continuous online), Colorimetric (DPD reagent produces color proportional to chlorine - accurate but reagent-based), and ORP (indirect measurement of oxidizing potential - fast response, low maintenance). Free chlorine measures HOCl/OCl-; total chlorine includes combined chlorine (chloramines). Applications: drinking water treatment, pool water, cooling water, and wastewater disinfection. Selection based on chlorine type (free/total), accuracy requirement, maintenance capability, and cost. Amperometric most common for online process control.