Paper-Based Colorimetric pH Test Strip Using Bio-Derived Dyes

Area of Science:

• Green Chemistry
• Analytical Chemistry
• Natural Product Chemistry

Background:

• Synthetic dyes raise environmental concerns in industrial applications.
• Conventional pH measurement tools can be expensive and complex.
• Natural dyes offer a sustainable and cost-effective alternative for various industrial needs.

Purpose of the Study:

• To explore the pH-responsive properties of natural organic dyes.
• To develop a novel pH indicator using natural dye pigments.
• To evaluate the potential of natural dyes as alternatives to conventional pH measurement techniques.

Main Methods:

• Extraction and analysis of pigments from forty vegetable species.
• Utilized a solvent mixture of 70% methanol/30% water for pigment extraction.
• Assessed the colorimetric response of dye extracts across a range of pH values.

Main Results:

• Pigments from cabbage, hibiscus flower, radish, and turmeric demonstrated significant color changes over a broad pH range.
• The color variations were easily distinguishable, correlating with specific pH levels.
• Dry pigment states exhibited optimal reactivity and stability for pH indication.

Conclusions:

• Natural dyes, particularly from cabbage, hibiscus, radish, and turmeric, are effective pH indicators.
• These findings support the use of natural dyes as a sustainable and economical substitute for traditional pH measurement methods.
• This research highlights a novel application for natural dyes in industrial pH verification.