Bromothymol Blue is a pH indicator used for measuring pH around 7 in pools and fish tanks. It operates in the pH range 6.0 to 7.6 due to the presence of an electron withdrawing and donating groups like bromine atoms and alkyl substitutents respectively. In the laboratory, it is used as a biological slide stain as well as used in obstetrics for detecting premature rupture of membranes. Further, it is used for the observation of photosynthetic activities and a respiratory indicator. In addition to this, it is used to define cell walls or nuclei under the microscope.
Acid-base indicator: pH 6.0 - 7.6.
Suwantarat, N.; Watkins, T.; Lee, R.; Carroll, K. C.; Zhang, S. X. False-positive reaction of L-canavanine glycine bromothymol blue medium with Candida famata. J. Clin. Microbiol. 2014, 52 (4), 1308-1309.
El-Nahhal, I. M.; Zourab, S. M.; Kodeh, F. S.; Abdelsalam, F. H. Sol-gel encapsulation of bromothymol blue pH indicator in presence of Gemini 12-2-12 surfactant. J. Sol-Gel Sci. Technol. 2014, 71 (1), 16-23.