A simple and rapid colorimetric method for the determination of peracids in
the presence of excess hydrogen peroxide is described. The method is based
on the selective destruction of hydrogen peroxide by the enzyme catalase,
a procedure which leaves the peracid unaffected. The residual solution then
containing only peracid, can be assayed using the stoichiometric oxidation
of 2,2'-azino-bis-(3-ethyl-benzthiazoline-6-sulfonate) diammonium salt (AB
TS) in the presence of peroxidase, a reaction that can be quantified photom
etrically at 405 nm. The double-enzyme method was extended to microtiter pl
ate-based systems, thus providing an easy way of analyzing multiple samples
for their peracid content.