X-Gal Stock Solution Recipe

X-Gal = 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside.

Dissolve X-Gal at 20 mg/ml in 100% dimethylformamide (DMF) or DMSO (dimethyl sulfoxide). Use a glass or plastic vial and store at −20 °C in the dark. Discard when the color of the stock solution changes significantly. It is not necessary to sterilize X-Gal solutions.

Working concentration: use at a final concentration of 20 µg/ml in the plate.

Reference: Sambrook, J. and Russell, D.W. 2001. Molecular Cloning: A Laboratory Manual, 3rd edition. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. p. 1.123–1.125.

Good luck with your experiments!