Portable microfluidic titration using a cross-shaped microfluidic device and smartphone camera for on-site...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Portable Analytical Devices

Background:

• Conventional titration methods often require specialized laboratory equipment.
• Onsite quantitative analysis is crucial for field applications.
• Microfluidic devices offer miniaturization and potential for portable analytical systems.

Purpose of the Study:

• To develop a portable microfluidic titration system utilizing a smartphone camera as a detector.
• To optimize microfluidic device design for enhanced visual detection of the equivalence point.
• To validate the system's accuracy for quantitative analysis of acid concentration.

Main Methods:

• Design and evaluation of two cross-shaped microfluidic devices with different channel geometries.
• Optimization of an expanding-channel device for improved visual equivalence point detection.
• Smartphone-based image analysis of color changes using red channel intensity profiles.
• Acid-base titration of hydrochloric acid using bromothymol blue indicator.

Main Results:

• An expanding-channel microfluidic device demonstrated enhanced visibility of the equivalence point.
• A linear correlation was established between measured distance and hydrochloric acid concentration (25-150 mM).
• The system accurately analyzed acid concentration in a real hot-spring water sample, comparable to conventional methods.

Conclusions:

• The developed portable microfluidic titration system provides reliable quantitative analysis.
• The system eliminates the need for microscopes or specialized optical instruments.
• This technology holds significant potential for accessible onsite analytical applications.