Oxidants INDEX

Table 23. Comparison of the Electrochemical Oxidation Index (EOI) at Pt/Ti and Sn02- Anodes (ABB-Anode) with organic substances [45a, 287, 288]...

A simple method for assessing lipid oxidation is measuring the headspace concentration of hexanal by capillary GLC. Also, the total volatiles appearing in the chromatogram up to hexanal can be taken as oxidation index. The method was applied to determine the amounts of lipid peroxides present in rat liver cells. Enhancement of the hexanal concentration can be achieved on adding ascorbic acid (22), that reduces Fe(ni) present in the matrix to Fe(II), which catalyzes decomposition of hydroperoxides to aldehydes. Significant correlations are found between hexanal concentrations and various oxidation indices, such as TBARS (Section IV.D.2)" . ... 

FIGURE 4.2 Oxygen and nitrous oxide index of polypropylene-chloroparaffin mixtures, 95-5 wt%, with added antimony trioxide. (From Costa, L. et al., Polym. Degrad. Stabil., 14(2), 116, 1986. With permission.)... 

The Electrochemical Oxidation Index (EOI), which is the average value of the current efficiency during the oxidation, is determined from the ICE using the relationship (Comninellis and Pulgarin 1991) ... 

Table 2.5 Initial electrochemical oxidation index (EOI) determined for the various test substances using Pt and Sn02 anodes (Stucki et al. 1991)...

NOxEI Nitrogen Oxide Index PrOx Preferential Oxidizer... 

From the Instantaneous Current Efficiency (ICE) - time curve (Fig. 1) an average value can be calculated and defined as the Electrochemical oxidation Index (EOI)... 

The peroxide value is a normal oxidation index, which has to be carefnUy used because at high temperatures, hydroperoxide decomposition may be more rapid than formation thns, degradation is not reflected by this index. 

Oxidation index = Absorbance of Monitored Band Absorbance of Reference Band... 

Hydroperoxides determination is the key factor to measure the level and the behavior of the oxidation (Carlsson et al. 1987b, Lacoste and Carlsson 1991, Shen, Yu, and McKellop 1999). Scientific studies and the American Society for Testing and Materials (ASTM) oxidation index standard (ASTM F2102) usually give the quantity of ketones and other carboxyl species present as an index of the oxidation degree. It must be pointed out that ketones, though a product of the oxidative process, do not produce polymeric chain scissions and so they do not result in substantial reduction of tiie UHMWPE mechanical properties. Quantification of ketones is reliable only if the ratio between ketones and carboxylic acids remains constant through the entire oxidative process. 

In this work, the parameters Electrochemical Oxidation Index (EOI) and Electrochemical Oxygen Demand (EOD), involved in the electrochemical treatment of organic pollutants, are presented [1-6]. From these parameters, both the degree of oxidation (X) and the average oxidation state of carbon (Ox) in the wastewater can be calculated during treatment [6]. 

The Electrochemical Oxidation Index (EOI) expresses the average current efficiency for the oxidation of organics and is a measure of the ease of electrochemical oxidation of the target organic compound (or the wastewater under investigation) on the investigated anode material under the experimental conditions used. 

Oxidation can generally be defined by an oxidation index such as [163] ... 

The oxidation levels in the sterilized components were quantified using the ASTM oxidation index and found to vary considerably among radiation-sterilized polyethylene inserts, but not the gas sterilized inserts. None of the gas-sterilized components were found to contain detectable macroradicals, hydroperoxide content, or oxidation, regardless of whether or not they were highly crosslinked. 

FIGURE 14.4 The results of aging for 14 days at 70°C in 5 atmospheres of oxygen (ASTM F2003). The oxidation index is shown as a function of depth for X3 , N2A ac , 90TS and virgin UHMWPE after accelerated aging. 

FIGURE 14.5 Oxidation index as a function of time with thin films in air at 90°C. Accelerated aging of thin films (180 rm thickness) of material at 90°C in air again indicated that the oxidation resistance of X3 is similar to that of virgin UHMWPE. 

TABLE 14.3 Oxidation index and tensile properties for X3 as manufactured and after 5 years shelf aging... 

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