Selective electrochemical sensor for on-line chloramine quantification in water

Overview

This solution addresses the need for rapid, selective, and reagent-free quantification of chloramines in water. Chloramines are widely used as disinfectants in municipal water treatment, yet current monitoring methods require chemical reagents, are time-consuming, and cannot easily distinguish individual chloramine species. The proposed sensor leverages the selective reaction between chloramines and amines to form nitroso compounds, enabling direct electrochemical detection without the addition of chemicals. The technology is designed to function analogously to disposable glucose meter strips, providing water utilities and industrial operators with a simple, on-line measurement tool.

Technical specifications

Core sensing principle:

• Chloramines selectively react with surface-bound amines to form nitroso compounds at the electrode interface
• An amino-functionalized electrode binds chloramines under defined contact time, producing an electrochemical signal proportional to analyte concentration
• During off-time, the electrode surface is regenerated by electrolytic reduction of nitroso compounds back into amines, restoring sensing capability
• Limits of quantification below 0.1 mg/L are achievable, consistent with established electrochemical sensor performance

Design and format:

• Screen-printed strip format integrating working, counter, and reference electrodes
• Working electrodes functionalized with amino groups using molecular linkers
• Disposable strip configuration suitable for routine field use
• Selective response toward individual chloramine compounds (NH2Cl, NHCl2, NCl3) and their mixtures
• Selectivity evaluated against common interfering solutes in both ultrapure and real tap water matrices

Differentiation:

• No chemical reagents required during operation
• On-line quantification capability
• Regenerable electrode surface extends usability
• Species-level selectivity distinguishes individual chloramine compounds

Technology readiness level

The technology is at an early-to-mid development stage. The underlying chemistry—chloramine reactions with amines to form nitrosamines—has been established in prior research by the proposing team. The electrochemical detection approach is validated by analogous commercial devices such as disposable glucose sensor strips. Planned validation activities include fabricating screen-printed electrode strips with amino-functionalized working electrodes, testing responses to individual and mixed chloramine species in ultrapure and tap water, evaluating selectivity against common interferences, and determining limits of detection and quantification. The technology is positioned for collaborative development toward prototype validation and eventual field deployment.