H2O2 Determination by the I3- Method and by KMnO4 Titration

Analytical Chemistry (Impact Factor: 5.83). 66(18). DOI: 10.1021/ac00090a020

ABSTRACT The analysis of aqueous H2O2 at concentrations as low as 1 mu M is conveniently done by the I-3(-) method, which is based on the spectrophotometric determination of I-3(-) formed when H2O2 is added to a concentrated solution of I-. At 351 nm, epsilon(max) (I-3(-)) was measured to be 26 450 M(-1) cm(-1). By contrast, an apparent value of 25 800 M(-1) cm(-1) was determined from a calibration of the I-3(-) method against titration by permanganate. The difference could only be partially accounted for by the equilibrium between I-3(-), I-2, and I-. A further correction of similar to 1% was required and was traced to a side reaction between H2O2 and the buffer normally used in the I-3(-) method. A simple spectrophotometric procedure was developed which improves the sensitivity of the permanganate titration to 0.3 mu M H2O2. Measurements of H2O2 using the oxidation of ferrous ions (Fricke solution) and permanganate titration differed by less than 1%.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this research, different CuO nanostructures (heart/dumbbell-like and grass-like) were successfully synthesized via simple hydrothermal reactions at 130◦C with different amounts of Cu(NO3)2·2.5H2O in 20 mL H2O and 12 mL NH3·H2O for 6 h in the absence of any additive. The initial amount of Cu(NO3)2·2.5H2O was found to be critical for CuO morphology evolution. In addition to morphology study by scanning electron microscopy (SEM) and crystal structure study by X-ray diffraction (XRD), as-synthesized samples were characterized systematically by electrochemical methods including cyclic voltammetry (CV), amperometric detection (i–t) and electrochemical impedance spectroscopy (EIS). It was found that both heart/dumbbell-like and grass-like CuO nanostructures exhibited good electrochemical performance toward low concentrations of H2O2. High sensitivity, fast and linear response were achieved, which was mainly due to their large specific surface areas and efficient electron transport in corresponding reactions, making them promising candidates for efficient and precise non-enzymatic detection of H2O2.
    Sensors and Actuators B Chemical 03/2015; 208. DOI:10.1016/j.snb.2014.11.051 · 3.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The presence of natural organic matter (NOM) poses several challenges to the commercial practice of UV/H(2)O(2) process for micropollutant removal. During the commercial application of UV/H(2)O(2) advanced oxidation treatment, NOM is broken down into smaller species potentially affecting biostability by increasing Assimilable Organic Carbon (AOC) and Biodegradable Organic Carbon (BDOC) of water. This work investigated the potential impact of UV/H(2)O(2) treatment on the molecular weight distribution of NOM and biostability of different water sources. A recently developed flow cytometric method for enumeration of bacteria was utilized to assess biological stability of the treated water at various stages through measurement of AOC. BDOC was also assessed for comparison and to better study the biostability of water. Both AOC and BDOC increased by about 3-4 times over the course of treatment, indicating the reduction of biological stability. Initial TOC and the source of NOM were found to be influencing the biostability profile of the treated water. Using high performance size exclusion chromatography, a wide range of organic molecule weights were found responsible for AOC increase; however, low molecular weight organics seemed to contribute more. Positive and meaningful correlations were observed between BDOC and AOC of different waters that underwent different treatments.
    Water Research 07/2012; 46(16):5297-304. DOI:10.1016/j.watres.2012.07.017 · 5.32 Impact Factor
  • Source
    Journal of Membrane Science 01/2011; · 4.91 Impact Factor


Available from