>98% [HPLC]. Free PNP < 300ppm.
Chromogenic substrate for beta-acetyl hexosaminidase: S. Kyosaka et al., Chem. Pharm. Bull., 28, 2658 (1980). In the determination of acid hydrolases in Human platelets: C.A. Dangelmaier and H. Holmsen, Anal. Biochem., 104, 182 (1980).