DETERMINATION OF BIACETYL BY SENSITIZED PHOTOCHEMICAL KINETIC FLUOROMETRY

A new in-situ photochemical kinetic fluorimetric method was proposed f or the determination of biacetyl (BI). It is based on the sensitizatio n of BI on the photochemical reaction of amaranth (AM). AM, a nonfluor escent compound was converted into an intensively fluorescent compound in a slightly alkaline medium by the sensitized photochemical reactio n, and BI was indirectly determined by monitoring the change of the fl uorescence intensity. The determination can be carried out by fixed-ti me method or tangent method. The kinetic behavior of the reaction and the effects of some experimental conditions were investigated and disc ussed. The calibration graph was rectilinear from 1.0 ng ml-1 to 10.0 mug ml-1 of BI (r = 0.999), the limit of detection was 1.0 ng ml-1, an d the coefficient of variation was 0.44% for 0.90 mug ml-1 of BI (n = 6). The mechanism for the sensitization of BI was examined and the tri plet-triplet energy transfer, in which BI acted as the energy donor an d AM as the energy acceptor, was suggested to be the main cause. Its a pplication to real samples has been tested.