Amine-modified carbon nanomaterial electrode for amperometric total chlorine sensing

Overview

This solution is an amperometric sensor platform designed for accurate, low-cost determination of total chlorine in water. It builds on a validated amine-modified graphite electrode for free chlorine sensing and extends the approach to total chlorine using amine-modified carbon nanotubes and graphene. The sensor is integrated with pH and temperature sensors on a single compact substrate, enabling real-time calibration and compensation for accurate readings across varying water conditions. With a total sensor footprint of 25 mm x 75 mm and a component cost under $2, the platform offers a practical path to reagent-less, in-line chlorine monitoring for drinking water utilities, bottled water producers, and industrial water treatment operations.

Technical specifications

• Amine-modified carbon nanotube and graphene electrode for amperometric total chlorine detection
• Integrated free chlorine, pH, and temperature sensors on a common substrate for real-time compensation
• Sensor dimensions of 25 mm x 75 mm for compact in-line deployment
• Free chlorine sensor performance: sensitivity of 186 nanoampere per ppm, hysteresis below 0.3 ppm, and high selectivity
• Custom-designed readout electronics tailored to the amperometric sensing platform
• Stable, solid-state silver/silver chloride reference electrode for long-term in-line operation
• Reagent-less operation, eliminating the need for chemical consumables during measurement
• Total component cost for the free chlorine, pH, and temperature sensor stack under $2

Technology readiness level

The underlying free chlorine sensor has been laboratory-validated on amine-modified graphite electrodes and tested with tap and bottled water samples, demonstrating high sensitivity, low hysteresis, and high selectivity. The next stage of development focuses on translating this performance to amine-modified carbon nanotube and graphene electrodes for total chlorine sensing, optimizing carbon nanomaterial combinations and electrochemical potentials, and integrating a solid-state silver/silver chloride reference electrode. Custom readout electronics are being developed to support in-line deployment, positioning the technology for pilot testing and field validation in water monitoring applications.