Full-range optical pH sensor based on imaging techniques.

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Accurate pH measurement is crucial across various scientific disciplines.
• Existing methods can be complex, expensive, or limited in range.

Purpose of the Study:

• To develop a new, cost-effective, disposable optical sensor array for full-range pH determination (0-14).
• To evaluate different predictive models for accurate pH sensing using colorimetric data.

Main Methods:

• Immobilization of pH indicators in polymeric membranes to create a multi-element sensor array.
• Utilizing a commercial scanner to capture color changes and analyzing the hue (H) component in the HSV color space.
• Comparing Linear, Sigmoid competition, and Sigmoid surface models for pH prediction based on hue data.

Main Results:

• The Sigmoid competition model achieved the lowest mean square error (0.0751) for pH prediction across the 0-14 range.
• The sensor demonstrated high sensitivity, selectivity, and accuracy, validated against potentiometric methods.
• The color-based sensor provides robust and precise pH measurements.

Conclusions:

• The developed disposable optical sensor array offers a simple, rapid, and inexpensive solution for broad pH sensing.
• This colorimetric approach provides comparable results to more complex optical sensing techniques.
• The method is suitable for various applications requiring accurate full-range pH monitoring.