Notes: Ochratoxin B-13C20 (OTB-13C20) is intended for use as an internal standard for the quantification of ochratoxin B (Item No. 16167) by GC- or LC-MS. OTB is a mycotoxin that has been found in Aspergillus and is a non-chlorinated derivative of OTA (Item No. 11439).{43719} Unlike OTA, OTB is not genotoxic to HepG2 cells but does inhibit cell division when used at concentrations ranging from 1 to 25 µg/ml.{26426} It induces mortality (LC50 = 700 nM) and craniofacial malformations (EC50 = 200 nM) in Xenopus embryos.{26425} OTB has been found in poultry feed.{72197}