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  • 18470 - Bromothymol Blue sodium salt

18470 Sigma-Aldrich

Bromothymol Blue sodium salt

for microscopy (Bot., Hist., Vit.), indicator (pH 6.0-7.6)

Synonym: 3′,3′′-dibromothymolsulfonephthalein sodium salt, Bromthymol Blue sodium salt

  • CAS Number 34722-90-2

  • Empirical Formula (Hill Notation) C27H27Br2NaO5S

  • Molecular Weight 646.36

  •  Beilstein/REAXYS Number 6887926

  •  EC Number 252-169-7

  •  MDL number MFCD00077263

  •  PubChem Substance ID 57647742



Related Categories Analytical Reagents, Analytical/Chromatography, Base Ingredients for Media, Indicators, Microbiology,
grade   for microscopy (Bot., Hist., Vit.)
  for molecular biology
  indicator (pH 6.0-7.6)
form   powder
visual transition interval   6.0 - 7.6, yellow to blue
storage temp.   room temp


General description

Bromothymol blue is a pH indicator for weak acids and bases. In neutral solution, it appears bluish-green. At pH above 7.6 it appears blue, and at pH below 6.0 it appears yellow.
Bromothymol blue (BTB) is an anionic dye. It can be protonated or deprotonated to generate yellow or blue. BTB helps to make ion-pair complex, that is used to identify several pharmaceutical compounds with the help of extractive spectrophotometric methods.


Suitable for use:
• In preparations of pH indicator solutions
• In phospholipid staining on tissues and cells prepared on microscopy slides

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 


Certificate of Analysis


Titrette from Brand
Protocols & Articles


Microbiology Introduction

An initial aim of all microbiologists is the reproducible growth of their microbial cultures, no matter whether the microorganisms are of natural origin or have been genetically engineered by man. Re...
Keywords: Absorption, Aerobic, Anaerobic, Antibiotics, Antimicrobials, Buffers, Culture media, Diffusion, Environmental, Filtration, Genetic, Growth factors, Metabolism, Phase transitions, Precipitation, Reductions, Respiration, Sample preparations, Vitamins

Peer-Reviewed Papers


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