Flow-injection Spectrophotometric Determination of N-acetyl-L-cysteine Based on Coupled Redox-complexation Reaction

Abstract

Abstract. A flow-injection spectrophotometric method is developed for determination of N-acetyl-Lcysteine (NAC) in pharmaceutical formulations. The method is based on coupled redox-complexation reaction, the first step of which is the reduction of Fe III by NAC; the second one includes the complexation of Fe . The analytical frequency was 60 h -1 . Usual excipients used as additives in pharmaceuticals do not interfere with the analysis of NAC. The proposed method is simple, rapid, sensitive, accurate and precise (repeatability RSD 0.29 %, n = 10), and can be applied for determination of NAC in pharmaceutical formulations up to nanomole quantity. (doi: 10.5562/cca1753)

Kinetic Spectrophotometric Determination of N-Acetyl-L-cysteine Ethyl Ester (NACET) Generating Chromogenic Copper(I)Ln Complexes with Different Ligands

“…[29] The standard potential of Cu(II)/Cu(I) couple in the solution of BCS could not been calculated because cyclic voltammetry experiments revealed irreversible redox behavior, thus precluding the application of the Nernst formula to determine its Cu(I) stability constant. [30] The formal redox potential of Fe(III)/Fe(II) couple in solution with 1,10-phenanthroline is much higher (1.197 V); the formal potential of the Fe(III)/Fe(II) couple in solution with TPTZ (0.578 V) [31] is comparable to the formal potential of the above mentioned Cu(II)/Cu(I) systems. Therefore, Fe(III)/Fe(II) systems have thermodynamic predisposition to react with NACET, but the reaction is rather slow probably due to kinetic reasons.…”

“…Among the described indirect spectrophotometric procedures one of the most common approaches to the determination of NAC is based on the coupled redox complexation reaction. The first step is the reduction of Fe(III) by NAC, followed by the determination of produced Fe(II) using various chromogenic reagents: 1,10-phenantroline, [4,8,12] hexacyanoferrate(III), [13] ferrozine, [6] 2,4,6-trypyridyl-striazine [9,18] and ferricyanide. [14] Cu(II)-neocuproine has also been used for the analysis of NAC of which the sulfhydryl group (SH) reduces Cu(II)-neocuproine to the chromogenic Cu(I)-neocuproine.…”

“…In the literature, there have been reported many spetrophotometric methods for the determination of NAC. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] One group of described methods involves redox reactions with NAC in which a colored compound is formed or decomposed during determination. Among the described indirect spectrophotometric procedures one of the most common approaches to the determination of NAC is based on the coupled redox complexation reaction.…”

Kinetic Spectrophotometric Determination of N-acetyl-L-cysteine Based on the Reduction of Copper(II)-neocuproine Reagent

“…5,8,23,24,[28][29][30]35 There are few developed spectrophotometric methods based on the reduction of the Fe III to Fe II with NAC, followed by the complexation of Fe II with different reagents: 1,10-phenanthroline (phen), 5,23,28 ferrozine, 8 2,4,6-trypyridyl-s-triazine (TPTZ), 24,35 hexacyanoferrate(III) 29 and ferricyanide. 30 The authors have developed kinetic spectrophotometric methods for determination of NAC using Fe IIIphen reagent 23 The Cu(II)-neocuproine reagent is milder and therefore more selective oxidant than Fe III -phenantroline reagent.…”

Determination of Trace Iron in the Boiler Water Used in Power Generation Plants by Solid-phase Spectrophotometry

“…13,19 Therefore, the developed color fades quickly in an acidic solution at a pH lower than 3; in addition, the precipitation caused by the hydrolysis of Fe(III) in a weak acidic solution (pH higher than 3.8) was reported by some researchers. 20 The pH effect on the color development is shown in Fig. 1, indicating that the range of pH 3 -4 was best for the formation of the Fe(TPTZ)2 2+ complex.…”