Toluidine blue is a basic thiazine metachromatic dye with high affinity for acidic tissue components.
It stains nucleic acids blue and polysaccharides purple and also increases the sharpness of histology slide images. It is especially useful today for staining chromosomes in plant or animal tissues
Toluidine Blue Stock Solution:
1g in 100 mL 70% ethanol
NaCl acid solution
1% NaCl aqueous, pH between 2 - 2.5 (w/ glacial acetic acid)
Working toluidine solution
1 part toluidine stock solution : 9 parts NaCl-Acid
Make this solution fresh and discard after use. pH higher than 2.5 will make staining less contrast.