Determination chlorine residuals

This sodium carbonate fusion - titration procedure is capable of determining chlorine residues in amounts down to 50 ppm in polyalkenes and polyalkene copolymers. 

This is an indirect method of analysis because the chlorine-containing species do not react with the titrant. Instead the total chlorine residual oxidizes l to l3 , and the amount of 13 is determined by the redox titration with Na282 03. 

One of the most important applications of redox titrimetry is in evaluating the chlorination of public water supplies. In Method 9.3 an approach for determining the total chlorine residual was described in which the oxidizing power of chlorine is used to oxidize R to 13 . The amount of 13 formed is determined by a back titration with 8203 . 

The methods described earlier for determining the total, free, or combined chlorine residual also are used in establishing the chlorine demand of a water supply. The chlorine demand is defined as the quantity of chlorine that must be added to a water supply to completely react with any substance that can be oxidized by chlorine while also maintaining the desired chlorine residual. It is determined by adding progressively greater amounts of chlorine to a set of samples drawn from the water supply and determining the total, free, or combined chlorine residual. 

A sample from a public water supply is analyzed to determine the free chlorine residual, giving an absorbance of 0.113. What is the free chlorine residual for the sample in parts per million CI2 ... 

Recently it was shown that when DDT, benzene hexachloride, or toxaphene is fed or applied to cattle, such organic chlorine residue as may be present in the fatty tissues consists essentially of unchanged insecticide. Carter (12) demonstrated their presence by separating the fats and other oxygenated products with sulfuric acid-sodium sulfate mixture and determining total chlorine. In experiments with DDT Schechter (46) demonstrated its presence in fatty tissue and in butterfat by the Schechter-Haller colorimetric method (47). The residues were then tested for toxicity to houseflies in comparison with the known insecticides of the same concentration. In both cases the known insecticide gave the same mortality as the residue. 

Wong [8] found that the determination of residual chlorine in seawater by the amperometic titrimetic method, potassium iodide must be added to the sample before the addition of the pH 4 buffer, and the addition of these two reagents should not be more than a minute apart. Serious analytical error may arise if the order of addition of the reagents is reversed. There is no evidence suggesting the formation of iodate by the reaction between hypobromite and iodide. Concentrations of residual chlorine below 1 mg/1 iodate, which occurs naturally in seawater, causes serious analytical uncertainties. 

Wong [8] reported that the losses of chlorine are not related to the formation of iodate by the oxidation of iodide by hypobromite. The presence of iodate in seawater may cause significant uncertainty in the determination of small quantities of residual chlorine in water. Determinations of residual chlorine at the 0.01 mg/1 level are of questionable significance. 

Carlson and Weberg [ 12] have also studied the interference from iodate during the iodometic determination of residual chlorine in seawater. These workers confirmed that due to the presence of naturally occurring iodate, results from the iodometric determination carried out at pH 2 were up to 20% higher... 

Mobile phase 3 may be used for the detection and semi-quantitative determination of residual N-bromosuccinimide. Thereby, the plate is sprayed with water and then placed in a chlorine atmosphere for 10 minutes. Excess chlorine is removed by placing the plate in a stream of warm air for another 10 minutes. After spraying with o-toluidine reagent, the evaluation is made against a dilution of N-bromosuccinimide. 

Ferric hydroxide can be quantitatively determined. The rate of removed chlorine residues was approximately 100%. Table 13.10 and Table 13.11 show... 

Example 17.8 Referring to Figure 17.1, if a dosage of 1.8 mg/L is administered, determine the amount free chlorine residual that results, the amount of combined residual that results, and the amount of combined ammonia chloramine residual that results. Also, determine the amount of organic chloramine residual that results. 

Phenylarsine oxide is used as a titrant for the direct and indirect determination of residual chlorine and ozone in water and wastewater. Preliminary investigations on the direct measurement of PAO by differential pulse polarography (DPP) indicate that this technique is a promising method for lowering the detection limits in the indirect measurement of these oxidants. The control of pH is a necessary consideration in free and combined chlorine analysis with as well as the stability and measurement of... 

Chlorine residual 12a. Chlorine residual too high. 12a. Determine toxicity level 12a. 

Testing procedure A standardized procedure which requires choice of solvent for extraction. In PE determinations, xylene was used as a solvent." A more complex procedure was used to determine the gel content in radiation crosslinked PVC filled with calcium carbonate. The compound was extracted with tetrahydrofuran, and non-dissolved residue was determined. This residue was then used for determination of chlorine by the Schoniger method. From the amount of chlorine, the concentration of polymer was established. The remainder of the gel content was a filler embedded by gel. " ... 

Elementary analysis measurements were carried out on an automatic CHN-analyser (Perkin-Elmer 2400, USA). The chlorine content was determined by AgNOj titration. The exact amount of carbon and chlorine residues in the catalysts was determined from three independent measurements. 

It was determined that microbial density of the biofdms on the equipment of drinking water supply system Yovkovtsy didn t depend on material type under high chlorine residual content in water. 

M. Trojanowicz, W. Matuszewski, and A. Hulanicki, Flow Injection Po-tentiometric Determination of Residual Chlorine in Water. Anal. Chim. Acta, 136 (1982) 85. 

D. J. Leggett, N. H. Chen, and D. S. Mahadevappa, Rapid Determination of Residual Chlorine by Flow Injection Analysis. Analyst, 107 1982) 433. 

In solution, HOCl and hypochlorite concentrations are commonly determined together by standard water analysis methods (AWWA, 1989). The sum of their concentrations is referred to as free available chlorine and is usually reported in parts per million (1 ppm free available chlorine = 1.4x 10" M). Detectable levels of free and combined (nitrogenous) available chlorine in treated water constitute a chlorine residual. In normal practice in North America, water utilities attempt to adjust chlorination levels to a small chlorine residual (2x 10" M or less) that is sufficient to survive throughout the drinking water distribution system all the way to the user s water taps. To achieve this level in the distribution lines, it may be necessary to add as much as 10 times higher amounts to the water in the plant, depending on the amount of reactive material in the source water and in the lines. 

On May 20, the first positive test for E. coli infection was reported, and the BGOS Health Unit called Stan Koebel twice to determine whether the infection might be linked to the water system. Both times, Stan Koebel reported acceptable chlorine residuals and failed to disclose the adverse test results. The Health Unit assured the public that the water was safe based on the assurances of Mr. Koebel. 

Determination of ozone residuals in water is quite difficult because of its rapid decomposition, volatility and reactivity. Most test methods available are variations of existing chlorine residual methods that are not specific for ozone. 

Different colorimetric test kits are available for the estimation of active chlorine. Bosch et al. [3] compared the performance of different colorimetric reagents for the determination of residual chlorine in water samples. The 3,3 5,5 -tetramethylbenzidine reagent produced the best results in the pH range of 1-2. In this case, the absorbance was measured at 450 nm and the detection limit was 2 ng/cm. ... 

Fusion with sodium carbonate is a very useful method for the fusion of polymers that, upon ignition, release acidic vapours, e.g., PE containing traces of chlorine or PVC, both of which, upon ignition, release anhydrous hydrogen chloride. To determine chlorine accurately in the polymer in amounts down to 5 ppm, hydrogen chloride must be trapped in a solid alkaline reagent (e.g., sodium carbonate). In this method, PE is mixed with pure sodium carbonate and ashed in a muffle furnace at 500 "C. The residual ash is dissolved in aqueous nitric acid, and then diluted with acetone. This solution is titrated potentiometrically with standard silver nitrate. 

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