Gradient-Based Colorimetric Array Sensor for Continuous Monitoring of Multiple Gas Analytes

Area of Science:

• Analytical Chemistry
• Materials Science
• Sensor Technology

Background:

• Colorimetry offers high sensitivity and selectivity for chemical sensing.
• Traditional colorimetric sensors are often single-use and difficult for parallel analyte detection due to irreversible reactions and bulky designs.

Purpose of the Study:

• To develop a reusable and parallel sensing system overcoming limitations of traditional colorimetric sensors.
• To demonstrate a gradient-based colorimetric array sensor (GCAS) for real-time analyte detection.

Main Methods:

• Inkjet-printing of different colorimetric sensing elements onto a porous substrate in parallel lines.
• Utilizing lateral analyte transport to create and track shifting color gradients.
• Employing a low-cost complementary metal-oxide semiconductor imager for real-time monitoring.

Main Results:

• Successful detection of three air pollutants using a single GCAS chip.
• Demonstration of 24-hour continuous monitoring of ambient ozone.
• Real-time conversion of color gradient shifts into analyte concentrations.

Conclusions:

• The developed GCAS offers a promising solution for sensitive, selective, and continuous multi-analyte monitoring.
• This technology overcomes the limitations of single-use and bulky traditional colorimetric sensors.
• GCAS provides a cost-effective and efficient platform for environmental monitoring applications.