Used as a pH indicator in analytical chemistry, particularly in spectrophotometric measurements for determining pH in seawater and other aqueous systems. It is effective in the pH range of approximately 7.4 to 9.0, where it changes color from yellow to purple, allowing precise detection of pH transitions in biological and environmental samples. Commonly employed in oceanography to measure carbonate system parameters, such as dissolved inorganic carbon and total alkalinity. Also utilized in laboratory settings for titrations and buffer monitoring where accurate pH indication in the slightly basic range is required.