Capillary flow-driven paper-based microfluidic sensor for NDMA detection in water

Area of Science:

• Analytical Chemistry
• Environmental Science
• Microfluidics

Background:

• N-Nitrosodimethylamine (NDMA) is a genotoxic contaminant frequently found in water sources.
• Current NDMA monitoring methods require complex sample preparation and instrumentation, limiting routine analysis.
• There is a need for accessible, on-site methods for detecting NDMA in water.

Purpose of the Study:

• To develop the first paper-based microfluidic assay for N-Nitrosodimethylamine (NDMA) detection.
• To integrate an on-chip photochemical nitrosation reaction for a complete workflow.
• To provide a user-friendly, low-cost platform for rapid, on-site water quality monitoring.

Main Methods:

• A paper-based microfluidic device was constructed using PET capillary channels and immobilized reagents.
• The assay involves a simple dip-and-fold operation for sample introduction and analysis.
• On-chip photochemical detection utilizes sodium 1-naphthol-4-sulfonate followed by Fe2+ and Co2+ complexation for colorimetric readout.

Main Results:

• The device achieved linear detection ranges of 0-100 ppm (Fe2+) and 0-30 ppm (Co2+), with low limits of detection (4 ppm and 1.5 ppm, respectively).
• High selectivity was ensured through interference studies and dual-channel readout.
• The platform demonstrated excellent device stability over four weeks and consistent recovery rates in various water samples (RSD < 10%).

Conclusions:

• This paper-based microfluidic platform offers a sustainable, cost-effective (<$0.2/device) alternative for NDMA detection in water.
• The user-friendly design facilitates on-site, rapid, and high-frequency water quality monitoring.
• The integrated on-chip photochemical reaction approach can be expanded for detecting a wider range of environmental contaminants.