High-sensitivity spectrofluorimetric determination of tiopronin based on inhibition of hemoglobin

A highly sensitive and simple spectrofluorimetric method for the determination of tiopronin based on its inhibitory effect on the hemoglobin-catalyzed reaction of H2O2 and l-tyrosine was developed. The concentration of tiopronin is linear with decreased fluorescence (Delta F) of the system under the optimal experimental conditions. The calibration graph is linear in the range 1.23 x 10(-8) to 3.06 x 10(-5) mol L-1 with a detection limit of 6.13 x 10(-9) mol L-1. The relative standard deviation was 4.38% for 11 determinations of 6.13 x 10(-6) mol L-1. This method can be used for the determination of tiopronin in pharmaceuticals with satisfactory results. Copyright (C) 2010 John Wiley & Sons, Ltd.