Fluorescent Detection of Aqueous N‑Nitrosodimethylamine via Photochemical Transformation and Affinity Capture

Abstract

N-Nitrosodimethylamine (NDMA) is a water-soluble carcinogen typically quantified using mass spectrometry coupled with chromatographic separation, which requires extensive sample preparation and sophisticated instrumentation. Here, we report a fluorescence-based detection strategy for NDMA in aqueous media that replaces column-based separation with affinity capture. Photochemical transformation of NDMA, followed by reaction with a biotinylated polymeric reagent, generates a biotin-labeled fluorescent product that can be selectively enriched through streptavidin–biotin interaction, enabling effective separation of the analytical signal from background. The assay is performed entirely in water without sample pretreatment, preconcentration, or solvent exchange. Under optimized conditions, quantitative detection is achieved in a plate-based format using only 100 μL samples, affording a limit of detection of 235 ppb. The chemical transformation is completed within 22 min, followed by rapid affinity capture via streptavidin-coated agarose beads or plates. The method is rigorously validated through spectroscopic characterization, selective capture experiments, and quantitative analysis, and demonstrates consistent performance in spiked commercial water samples. These results establish a chemically defined platform for chromatography-independent optical NDMA detection and provide a basis for further development toward scalable sensing formats built on streptavidin-functionalized solid phases.