FLOW-INJECTION FLUOROMETRIC-DETERMINATION OF PENICILLAMINE AND TIOPRONIN IN PHARMACEUTICAL PREPARATIONS

Two flow-injection methods for the fluorimetric determination of penic illamine and tiopronin are proposed. The procedures are based on the o xidation of these drugs by thallium(III). In hydrochloric acid medium the fluorescence of thallium(I) formed in the oxidation of penicillami ne or tiopronin is monitored using excitation and emission wavelengths of lambda(ex) = 227 nm and lambda(em) =419 nm respectively. Linear ca libration graphs were obtained between 3 x 10(-7) and 8 x 10(-6) M for penicillamine and between 8 x 10(-7) and 2 x 10(-5) M for tiopronin w ith sampling frequencies of 90 and 45 samples h(-1) respectively. The relative standard deviations were in the ranges 0.48-0.29% for penicil lamine and 1.04-0.31% for tiopronin. The applicability of the method t o the determination of both drugs in pharmaceutical preparations was d emonstrated by investigating the effect of potential interferences and by analysis of commercial preparations.