Determination of nitrite ions in environment analysis with a paper-based microfluidic device

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Nitrite ions are crucial environmental indicators, necessitating accurate detection methods.
• Existing sensors often lack sensitivity, selectivity, or are not cost-effective for widespread environmental monitoring.
• Microfluidic paper-based analytical devices (μPADs) offer advantages in portability, low sample volume, and disposability.

Purpose of the Study:

• To develop a novel silver ink-based microfluidic paper analytical device (Ag-μPAD) for sensitive and selective nitrite ion determination.
• To investigate the sensing mechanism and performance characteristics of the Ag-μPAD for nitrite detection.
• To validate the sensor's applicability in real-world environmental water samples.

Main Methods:

• Synthesis of silver ink comprising silver nanoparticles and nanowires.
• Fabrication of Ag-μPADs using pulsed light sintering for silver ink deposition.
• Electrochemical characterization of the Ag-μPAD chemiresistor.
• Quantitative analysis of nitrite ions using resistance measurements.
• Validation of sensor performance using SEM, EDS, and IR studies.

Main Results:

• The Ag-μPAD demonstrated high sensitivity and selectivity for nitrite ions.
• Two linear response ranges were observed for nitrite concentrations from 1.0 × 10-8 M to 3.2 × 10-3 M.
• A low limit of detection of 8.5 × 10-11 M was achieved.
• The sensor exhibited superior stability, a wider linear range, and lower detection limits compared to other paper-based sensors.
• Successful determination of nitrite in tap, river, and lake water samples.

Conclusions:

• The developed Ag-μPAD is a promising, cost-effective, and disposable platform for sensitive and selective nitrite detection in environmental water analysis.
• The pulsed light sintering method provides an efficient way to fabricate Ag-μPADs with excellent sensing capabilities.
• This technology holds potential for decentralized environmental monitoring and water quality assessment.