engleski

A novel detection approach based on coupled redox-complexation reaction with 2, 4, 6-Trypyridyl-s-triazine (TPTZ) as an chromogenic reagent and its application to flow-injection spectrophotometric determination of tiopronin {;N-(2-Mercaptopropionyl)-Glycine};

A flow injection spectrophotometric procedure for N-(2–mercaptopropionyl)-glycine (MPG) determination is proposed. The determination is based on coupled redox-complexation reaction between MPG, Fe(III) and 2, 4, 6-Trypyridyl-s-triazine (TPTZ). Firstly MPG reduces Fe(III) to Fe(II) and the reduced Fe(II) is rapidly converted to the highly stable, deep-blue colored Fe(TPTZ)22+. This colored complex was monitored at 593 nm. Optimal conditions for determining MPG are achieved by univariate method. A linear calibration curve is established in a concentration range of 4.0  10-6 to 2.0  10-4 mol L-1 MPG with regression equation y = 4704 x - 0.019 (R2 = 0.9998) (n = 10) and detection limit of 2.35  10-7. The analytical frequency was 60 h-1. The proposed method is simple, rapid, sensitive and reproducible (RSD 0.5%, n = 10), and can be applied for determination of MPG in pharmaceutical preparations up to nanomole quantity. Usual excipients used as additives in pharmaceuticals do not interfere with the proposed method.

tiopronin; N-(2-Mercaptopropionyl)-Glycine; Flow-injection spectrophotometry; pharmaceuticals

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