Paper-based microfluidic devices for electrochemical quantification of the explosive picric acid

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Environmental Science

Background:

• Picric acid (PA) is a hazardous explosive requiring sensitive detection methods.
• Existing analytical techniques for PA can be time-consuming and complex.
• Development of portable and high-throughput analytical tools is crucial for field applications.

Purpose of the Study:

• To develop a high-throughput analytical method for quantifying picric acid (PA).
• To integrate electrochemical chips with microfluidic paper-based analytical devices (µPADs).
• To demonstrate the applicability of the developed system for environmental water analysis.

Main Methods:

• Fabrication of a three-electrode thermoplastic chip using a 3D printing pen.
• Integration of the chip with circular paper structures to create µPADs.
• Electrochemical analysis using differential pulse voltammetry for PA reduction.
• Optimization of µPAD assembly, including paper substrate, injection volume, and detection potential.

Main Results:

• Achieved a sample throughput of (131 ± 14) injections per hour.
• Demonstrated a linear response for PA quantification from 10 to 100 µmol L⁻¹.
• Established a limit of detection of 5.0 µmol L⁻¹ for PA.
• Validated the system's applicability in lake water samples through recovery studies.

Conclusions:

• The proposed µPAD-based electrochemical system offers a practical and efficient tool for PA quantification.
• The method provides high-throughput analysis suitable for environmental monitoring.
• The use of 3D printing and paper-based devices presents a low-cost and accessible analytical solution.