Integrated Digital Microfluidic Platform for Colorimetric Sensing of Nitrite.

Area of Science:

• Analytical Chemistry
• Microfluidics
• Biosensing

Background:

• Nitrite quantification is crucial for food safety and environmental monitoring.
• Traditional methods often require complex equipment and manual operation.
• Digital microfluidic (DMF) platforms offer miniaturization and automation potential.

Purpose of the Study:

• To develop a portable, integrated digital microfluidic (DMF) platform for on-chip nitrite quantification.
• To enable repeatable colorimetric analysis using a novel DMF chip design.
• To provide a cost-effective and flexible alternative to existing nitrite detection methods.

Main Methods:

• A palm-size DMF platform was designed using printed circuit board (PCB) technology.
• An embedded aperture in the actuator electrode created a vertical light path for droplet measurement.
• The platform automated the Griess assay for nitrite detection without external pumps or valves.

Main Results:

• The DMF platform demonstrated good linearity (R² = 0.9974) for nitrite quantification.
• The system showed ignorable crosstalk, ensuring reusability.
• A low limit of detection (LOD) of 5 μg/L for nitrite was achieved.
• Successful application in determining nitrite levels in food products with reliable results and satisfactory recoveries.

Conclusions:

• The integrated DMF platform offers a flexible, portable, and cost-effective solution for nitrite analysis.
• The novel PCB-based DMF chip enables efficient on-chip colorimetric detection.
• This technology shows promise for environmental monitoring, food safety, and point-of-care testing.