UltraPure™ Guanidine Isothiocyanate Solution contains 4M Guanidine Isothiocyanate, 50mM Tris-HCL (pH 7.5), 25mM EDTA. It can be used in the experimental protocol for the operation of guanidine isothiocyanate - this method was originally proposed by Chirgwin et al. (1) and later by Han et al. /i>Modify(2) to isolate intact mRNA from tissue or cultured cells.