T3260 Sigma-Aldrich

Toluidine Blue O

Technical grade

Synonym: Basic Blue 17, Blutene chloride, Methylene Blue T50 or T extra, Tolonium chloride

  • CAS Number 92-31-9

  • Empirical Formula (Hill Notation) C15H16ClN3S

  • Molecular Weight 305.83

  •  Colour Index Number 52040

  •  EC Number 202-146-2

  •  MDL number MFCD00011934

  •  PubChem Substance ID 24900122



Related Categories Cell Biology, Hematology and Histology, Stains & Dyes, A to Z, Stains and Dyes, T-U-V More...
form   powder
composition   Dye content, ~80%
solubility   H2O: 1 mg/mL


General description

A metachromatic dye suitable for a wide variety of histological staining procedures.

Toluidine Blue O (TBO) is a thiazine dye of the quinone-imine family and is cationic in nature. It has been employed in polychromatic staining of paraffin embedded plant cell walls. It is a metachromatic dye suitable for a wide variety of histological staining procedures.


5, 25, 100 g in glass bottle


Toluidine Blue O has been used to stain a variety of specimens like mesenchymal cells, taste buds, osteoblasts, matrix, etc.

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 


Certificate of Analysis

Certificate of Origin

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.
How do I get lot-specific information or a Certificate of Analysis?
The lot specific COA document can be found by entering the lot number above under the "Documents" section.
How do I find price and availability?
There are several ways to find pricing and availability for our products.Once you log onto our website, you will find the price and availability displayed on the product detail page.You can contact any of our Customer Sales and Service offices to receive a quote. USA customers: 1-800-325-3010 orview local office numbers.
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.
Is there a difference between Toluidine Blue O and Toluidine Blue and which is best for staining tissue sections?
Toluidine Blue O and Toluidine Blue are generally regarded as synonyms.The dye can be found in 2 forms. There is a chloride form and zinc chloride double salt. Products T3260 and 198161 are the chloride form. This is the formcertified by the Biological Stain Commission. The dye listed as simply Toluidine Blue, Product 89640, is the zinc chloride double salt. For routine use today, the chloride formshould be utilized. The product numberrecommended forbiological/histological stainingis Product 198161, Toluidine Blue O. This product has been found to provide acceptable staining of tissue by the Biological Stain Commission.Products 198161 and 89640 have not been suitability tested for the staining of tissue sections.
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