Abstract: A measuring system and method are disclosed for measuring an ion concentration in a process liquid using capillary electrophoresis. In at least one embodiment, the measuring system includes an inlet connectable to a process for supplying the process liquid; a throughflow system connected to the inlet; a capillary electrophoresis measuring device connected to the throughflow system and provided with a detector and measuring capillary; and a data processing unit connected operatively during use to the capillary electrophoresis measuring device.