1. 3,3,5,5- Tetramethylbenzidine (TMB) series TMB: Bio ≥ 99.5% [54827-17-7] AR ≥ 99% TMB·2HCl: Bio ≥98% [64285-73-0] TMB·2H2SO4:Bio ≥98% TMB-N-Propane sulfonic acid, Sodium Salt: AR≥ 99% TMB is a new, highly sensitive chromogenic reagent and diagnostic clinical reagent.