1. Acid-Base Indicators

This is its most basic and widespread application. In analytical chemistry and teaching experiments, it is used to indicate the acidity or alkalinity of solutions, especially with a noticeable color change in the pH range of 5.2-6.8.

2. Non-Aqueous Titration Analysis
Suitable for titration analysis in non-aqueous solvent systems (such as organic solvents), serving as an indicator of endpoint changes.

3. Chromatographic Analysis
In fields such as amino acid chromatography, it can be used as an internal standard.

4. Adsorption Indicators
Used in analyses such as precipitation titrations, the endpoint is determined by the color change caused by the adsorption and desorption of the indicator on the precipitate surface.

5. Specific Chemical Analysis
For example, it serves as a key reagent in specific analytical methods such as the silver salt titration of thiocyanate and spectrophotometric precipitation of serum proteins.

6. Biological Research
Used to assess the integrity of yeast cell membranes. When the cell membrane is damaged, dyes can enter the cell for detection.