Combined "dual" absorption and fluorescence smartphone spectrometers

Area of Science:

• Spectroscopy
• Analytical Chemistry
• Mobile Technology

Background:

• Smartphone-based spectroscopy offers a portable and cost-effective alternative to traditional laboratory instruments.
• Existing smartphone spectrometers often lack integrated, versatile excitation sources for both absorption and fluorescence measurements.

Purpose of the Study:

• To develop and demonstrate a combined dual absorption and fluorescence smartphone spectrometer.
• To integrate multiple excitation sources (UV, blue, white LEDs) into a single, portable device powered by a smartphone.

Main Methods:

• A custom-designed spectrometer utilizing a smartphone's camera (CMOS chip) and flash LED.
• Incorporation of interchangeable UV (370 nm) and blue (450 nm) LEDs alongside the white LED for excitation.
• Use of a low-cost, nano-imprinted diffraction grating for spectral dispersion.
• Development of a customized application for data acquisition and analysis.

Main Results:

• Successful acquisition of absorption and fluorescence spectra using the smartphone spectrometer.
• Demonstrated detection over a 300 nm spectral span with a resolution of 0.42 nm/pixel.
• Validated the system with a pH-sensitive fluorescent probe and a Zn2+-sensitive fluoro-ionophore.

Conclusions:

• The developed smartphone spectrometer is a self-contained, portable, and versatile analytical tool.
• The system enables dual absorption and fluorescence measurements, expanding the capabilities of mobile spectroscopy.
• The design is scalable, allowing for the integration of additional excitation sources for broader applications.