FLUOROMETRIC-DETERMINATION OF PHENOTHIAZINE-DERIVATIVES BY PHOTOOXIDATION IN A FLOW-INJECTION SYSTEM

Flow-injection analysis (FIA) was combined with photochemically induce d fluorescence (PF) detection for the determination of four phenothiaz ine derivatives, including unsubstituted phenothiazine, thionine, Azur e A and Methylene Blue. The working analytical parameters (flow-rate, injected volume, photoreactor length) were optimized. Linear calibrati on graphs were obtained over about two orders of magnitude, with relat ive standard deviation within the range 1-2.3%. Limits of detection we re between 13 and 35 ng/ml, according to the compound. The FIA-PF meth od was applied to the determination of phenothiazines in urine samples . Mean recoveries ranged from 94 to 117%.