For optimal results in HPLC analysis, it is recommended to measure absorbance at a wavelength that matches the absorption maximum of the compound(s) being analyzed. The UV spectrum shown can assist in selecting an appropriate wavelength for your analysis. Please note that certain mobile phases and buffers may block wavelengths below 230 nm, rendering absorbance measurement at these wavelengths ineffective. If detection below 230 nm is required, it is recommended to use acetonitrile and water as low UV-transparent mobile phases, with phosphoric acid and its salts, sulfuric acid, and TFA as buffers.
For some compounds, the UV-Vis Spectrum is affected by the pH of the mobile phase. The spectra presented here are measured with an acidic mobile phase that has a pH of 3 or lower.

HPLC Method for Thymol blue on Primesep 100 by SIELC Technologies

High Performance Liquid Chromatography (HPLC) Method for Analysis of Thymol blue 

Thymol Blue is a sulfonephthalein dye with C₂₇H₃₀O₅S molecular formula. It is typically used as a pH indicator. Despite it’s name, it is only blue at higher pH levels, turning from blue to yellow when going basic to neutral and from yellow to red when changing from relatively acidic to very acidic. Due to the split in transition stages, it us considered a diprotic acid.

Thymol blue can be retained and analyzed using the Primesep 100 stationary phase column. The analysis utilizes an isocratic method with a simple mobile phase consisting of water and acetonitrile (MeCN) with a formic acid buffer. Detection is performed using UV.