Tolonium chloride

Tolonium chloride
IUPAC name (7-amino-8-methyl- phenothiazin-3-ylidene)- dimethyl-ammonium
Other names Toluidine blue O
Identifiers
CAS number	92-31-9
PubChem	7084
ChemSpider	11239098 Y
MeSH	Tolonium+chloride
Jmol-3D images	Image 1
SMILES [Cl-].CN(C)c1ccc2nc3cc(C)c(N)cc3[s+]c2c1
InChI InChI=1S/C15H16N3S.ClH/c1-9-6-13-15(8-11(9)16)19-14-7-10(18(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H/q+1;/p-1 Y Key: HNONEKILPDHFOL-UHFFFAOYSA-M Y InChI=1/C15H16N3S.ClH/c1-9-6-13-15(8-11(9)16)19-14-7-10(18(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H/q+1;/p-1 Key: HNONEKILPDHFOL-REWHXWOFAY
Properties
Molecular formula	C15H16N3S+
Molar mass	270.374 g/mol
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Tolonium chloride (INN, also known as toluidine blue) is a blue cationic (basic) dye used in histology.

Test for lignin

Toluidine blue solution is used in testing for lignin, a complex organic molecule that bonds to cellulose fibres and strengthens and hardens the cell walls in plants. A positive toluidine blue test causes the solution to turn from blue to blue-green. A similar test can be performed with phloroglucinol-HCl solution, which turns red.

Other histological uses

Toluidine Blue is often used to identify mast cells, by virtue of the heparin in their cytoplasmic granules. It is also used to stain proteoglycans and glycosaminoglycans in tissues such as cartilage. The strongly acidic macromolecular carbohydrates of mast cells and cartilage are coloured red by the blue dye, a phenomenon called metachromasia.

Alkaline solutions of toluidine blue are commonly used for staining semi-thin (0.5 to 1 μm) sections of resin-embedded tissue. At high pH (about 10) the dye binds to nucleic acids and all proteins. Although everything in the tissue is stained, structural details are clearly visible because of the thinness of the sections. Semi-thin sections are used in conjunction with ultra-thin sections examined by electron microscopy.

References

Carson FL (1997) Histotechnology. A Self-Instructional Text. 2nd ed. American Society of Clinical Pathologists, Chicago.

Green FJ (1990) The Sigma-Aldrich Handbook of Stains, Dyes and Indicators. Aldrich Chemical Company, Milwaukee, Wisconsin.

Horobin RW, Kiernan JA, Eds (2002) Conn's Biological Stains. A Handbook of Dyes, Stains and Fluorochromes for Use in Biology and Medicine. 10th ed. BIOS, Oxford.

Kiernan JA (2008) Histological and Histochemical Methods: Theory and Practice. 4th ed. Scion, Bloxham, UK.