A detection tube for cholinesterase inhibiting compounds

The enzyme butyrylcholinesterase from horse serum catalyses the hydrolysis of certain esters. The orange-red 2,6-dichloroindophenyl acetate will be converted by the enzyme into a deep blue alcohol. The colour transformation does not occur when the enzyme is inactivated. By making use of this biochemical reaction a cheap and simple, but very sensitive and specific detection tube could bedeveloped. The tube comprises a breakable ampoule with an aqueous buffer solution, a freeze-dried preparation of the chromogenic ester with a filler promoting its dissolution, a freeze-dried preparation of butyrylcholinesterase with a filler promoting its stability, and an indication layer. DDVP can be detected at concentrations as low as 0.4 mg/m3, when the sampled airvolume is 21.