Fully Integrated, Automated, and Smartphone Enabled Point-of-Source Portable Platform With Microfluidic Device for...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Biomedical Engineering

Background:

• Nitrite accumulation in environmental and physiological systems poses significant health risks.
• Accurate, real-time, point-of-source detection of nitrite is essential for timely intervention.
• Existing detection methods may lack portability, affordability, or automation for field applications.

Purpose of the Study:

• To design and develop a standalone, portable, low-cost, automated, and integrated microfluidic system for nitrite detection and quantification.
• To enable quick, on-site analysis of nitrite levels.
• To provide a user-friendly platform for real-time nitrite monitoring.

Main Methods:

• A polydimethylsiloxane (PDMS) microfluidic device was utilized for a controlled Griess reaction.
• A 3D-printed syringe pump was developed for precise sample and reagent delivery.
• Photometric detection was implemented using LED and photodiode, coupled with a custom transimpedance amplifier circuit.
• System integration and control were achieved using an off-the-shelf microprocessor and a Bluetooth-connected smartphone application.
• Spectrophotometric validation and calibration were performed to correlate voltage output with nitrite concentration.

Main Results:

• The developed system demonstrated a limit of detection (LOD) of 0.07103 ppm and a limit of quantification (LOQ) of 0.21524 ppm.
• The system exhibited good repeatability for nitrite quantification.
• A calibration equation was established for converting voltage output to absorption via the smartphone application.
• The integrated system, housed in a 3D-printed platform, proved to be easy to use and affordable.

Conclusions:

• The developed microfluidic system offers a simple, real-time, and affordable solution for point-of-source nitrite quantification.
• The portable and automated nature of the device facilitates rapid environmental and physiological monitoring.
• This technology has the potential to significantly improve preventative measures against nitrite-related health risks.