Development of an image-based fluorometer with smartphone control for paper analytical devices

Area of Science:

• Analytical Chemistry
• Instrumentation
• Spectroscopy

Background:

• Paper analytical devices (PADs) offer a low-cost platform for chemical sensing.
• Existing fluorescence detection methods for PADs can be complex and require specialized equipment.
• Developing portable and user-friendly analytical instruments is crucial for point-of-care and field applications.

Purpose of the Study:

• To construct and evaluate a novel fluorometer for PADs.
• To utilize a smartphone for instrument operation and real-time image-based detection.
• To demonstrate the device's capability for quantifying analytes like quinine and riboflavin.

Main Methods:

• A rotating circular PAD with analytical plates was used under UV LED irradiation.
• A custom smartphone application performed sequential plate analysis and RGB intensity collection.
• The fluorometer was tested for the determination of quinine in beverages and riboflavin in supplements.

Main Results:

• Linear calibration ranges (R² > 0.99) were achieved for both analytes from 2.0 to 10.0 mg L⁻¹.
• Limits of detection were estimated around 1.0 mg L⁻¹.
• The method demonstrated good precision (ca. 4.0% signal deviation) and accuracy compared to a reference method.

Conclusions:

• The developed smartphone-based fluorometer is a precise and accurate analytical tool for fluorescence detection in PADs.
• The system is capable of analyzing both steady-state and transient fluorescent signals.
• The strategy shows potential for enhancing sensitivity through pre-concentration techniques on PADs.