Spectrophotometric Determination of Tiopronin, Penicillamine and Captopril

Spectrophotometric Determination of Tiopronin, Penicillamine and Captopril

Tamara Abd Al -Rahman Kamal Three methods for the spectrophotometric determination of tiopronin, penicillamine and captopril are presented. They are based on the oxidation of these amino acids by irori (III) in the presence of complexing reagent (ferrozine, 1,10-phenanthroline or DI-2-pyridyl ketone thiophene hydrazone (DPKTH)) whereby colored complexes are formed. These complexes have maximum absorbance at 562 nm when using ferrozine, 510 nm when using 1,10- phenanthroline and 676 nm when using DPKTH . All factors affecting the sensitivity and reproducibility of the method were studied such as, effect of pH, time, temperature, ionic strength, effect of iron (111) concentration, effect of foreign ions concentration. The methods were applied for the determination of tiopronin-ferrozine system in the range of linearity 2.2-83.0 ppm, the detection limit was at 2.2 ppm and the molar absorptivity was2.Oxl04 l mol-' cm-', for tiopronin - 1,10- phenanthroline system the range of linearity was 4.9176.0 ppm, the detection limit was 4.9 ppm and the molar absorptivity was I .0x1041 mol-' cm-', for tiopronin - DPKTH system the range of linearity was 4.6- 176.0 ppm and the detection limit was 4.6 ppm with molar absorptivity 1.Ox104 1 mol-' cm-l. The determination of penicillamine was in the range of linearity 0.4015.1 ppm and the detection limit was 0.40 ppm with molar absorptivity l .Ox10'lmol-' cm-' when using penicillamine - ferrozine system, for penicillamine - DPKTH system the range of linearity was 4.2- 167.0 ppm and the detection limit was 4.2 ppm with molar absorptivity 1.0x104 1 mot-' cm-1. The determination of captopril was in the range of linearity 3.7- 201.2 ppm and the detection limit was 3.7 ppm with molar absorptivity 1.3x 104 1 mot-' cm-' when using captopril - ferrozine system, for captopril - 1,10- phenanthroline the range of linearity was6.9- 196.2 ppm and detection limit 6.9 ppm with molar absorptivity 1.2x10 1 mot-' cm-', for captopril - DPKTH system the range of linearity was 4.8- 209.8 ppm and the detection limit was at 4.8 ppm with molar absorptivity 1.1 x10'1 mol-' cm-' . Tamara Abd Al -Rahman Kamal Supervisors Prof. Maher Abu Eid Dr. Nidal Zatar June 1999 Zajel / An-Najah National University