Purity >98%. Monobromobimane is a thiol-reactive fluorogenic probe. It is cell-permeable, reacts rapidly at physiological pH with available thiol groups, and generates a stable fluorescent signal. Monobromobimane can be used to evaluate or quantify a variety of compounds containing reactive sulfur or thiol groups, including H2 S, glutathione, proteins, and nucleotides. The absorption and emission maxima for monobromobimane are 398 and 490 nm, respectively.