Flow-Injection Determination of Vanadium in Seawater Samples with Acidic Potassium Permanganate Chemiluminescence

Abstract

Chemiluminescence from the vanadium and potassium permanganate reaction was studied under acidic conditions to develop a sensitive method for vanadium determination using the formaldehyde enhancement effect. The method was successfully applied to the determination of vanadium in seawater. Experimental parameters were optimized, including acid concentration, potassium permanganate and formaldehyde concentration. A linear calibration graph was obtained in the concentration range of 2.0 × 10 -9 -5 × 10 -6 M with relative standard deviations (n = 4) in the range of 1.8 -3.1%. The detection limit (3s blank) was 8.0 × 10 -10 mol L -1 with a sample throughput of 100 h -1 . The effect of salinity and various interfering cations and anions were studied. The method was applied to determine total dissolved vanadium in seawater samples and certified reference materials after online reduction with amalgamated zinc column.

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. Only the reducing substances with standard (formal) potentials lower than 0.6 V would have the thermodynamic predisposition to interfere in the proposed method.…”

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

“…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.…”

“…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. [21,22] For the determination of NACET we tested reagents which have been previously used for its congener NAC.…”

Specific pH effect for selective colorimetric assay of glutathione using anti-aggregation of label-free gold nanoparticles

“…In recent decades, a host of detection approaches are utilized to monitor or quantify the variations of GSH in previous literatures, involving ow injection analysis, 9 high performance liquid chromatography (HPLC), 10 surface-enhanced Raman scattering (SERS), 11 electrogenerated chemiluminescence sensor (ECL), 12 electrochemical, 13 mass spectrometry (MS), 14 liquid chromatography followed by tandem mass spectrometry (LC-MS/MS), 15 nuclear magnetic resonance (NMR), 16 uorescence spectroscopy, 17 and colorimetry, [18][19][20][21] which could quantitatively detect and identify thiols but with drawbacks of complicated manipulations and low selectivity.…”