Thymol blue solution

Thymol Blue Solution is an aqueous indicator solution derived from thymolsulfonephthalein, and it serves as a sensitive tool for detecting pH changes across both acidic and basic ranges.

🏭⚗️ Production
Thymol Blue Solution is typically prepared by dissolving thinly powdered Thymol Blue in ethanol or dilute alkaline solution until a working concentration—commonly around 0.04% w/v—is achieved. The solution should be stored in a tightly sealed, light-protective container to preserve its effectiveness.

🔬 Properties
The dye appears as a brownish-green or reddish-brown crystalline powder that is essentially insoluble in water but dissolves readily in alcohol and dilute alkali. Its dual-range color transition makes it highly versatile: it shifts from red to yellow in the pH range of approximately 1.2 to 2.8, and from yellow to blue in the pH range of approximately 8.0 to 9.6. Thymol Blue has a molecular formula of C₂₇H₃₀O₅S and a molar mass of about 466.6 g/mol. In its solid crystalline form, it melts and decomposes around 221–224 °C.

🧪 Applications
Thymol Blue is widely used as a pH indicator in analytical and educational settings, valued for its clear and vivid color changes across a broad pH spectrum. It is often included in universal indicator mixtures and used for titrations needing dual-endpoint visualization. Due to its strong absorbance properties, it can also be employed in spectrophotometric measurements.

⚠️ Safety
Thymol Blue is considered harmful if swallowed or upon prolonged exposure, and it may cause mild irritation. Good laboratory practice includes handling the solution with protective gloves and eye protection, as well as storing it securely.