Iodometric determination

The former reaction, in particular, affords a convenient means of quantitative analysis by determination of the H2S (precipitated as CdS) and iodometric determination of the thiosulfate produced. 

Satisfactory 40% peracetic acid is obtainable from Buffalo Electrochemical Corporation, Food Machinery and Chemical Corporation, Buffalo, New York. The specifications given by the manufacturer for its composition are peracetic acid, 40% hydrogen peroxide, 5% acetic acid, 39% sulfuric acid, 1% water, 15%. Its density is 1.15 g./ml. The peracetic acid concentration should be determined by titration. A method for the analysis of peracid solutions is based on the use of ceric sulfate as a titrant for the hydrogen peroxide present, followed by an iodometric determination of the peracid present.3 The checkers found that peracetic acid of a lower concentration (27.5%) may also be used without a decrease in yield. The product was found to be sufficiently pure, after only one recrystallization from 60 ml. of petroleum ether (b.p. 40-60°) and cooling overnight to —18°, to be used in the next step. 

ISO 2270 1989, Non-ionic surface active agents. Polyethoxylated derivatives Iodometric determination of oxyethylene groups. 

In its reactions SsO shows properties typical for both sulfur homocycles and sulfoxides. With elemental chlorine SOCI2 and S2CI2 are formed, with bromine SOBr2 and S2Br2 are obtained. Water decomposes SsO to H2S and SO2 besides elemental sulfur while cyanide ions expectedly produce thiocyanate. The reaction with iodide in the presence of formic acid is used for the iodometric determination of the oxygen content [70] ... 

Thus in mixtures with various model hydroperoxides (reaction (24)), neither amine II nor nitroxide I had any effect on the iodometrically determined peroxide content after standing for a few days at RT. 

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... 

Example Estimation of chlorate —an oxidant by iodometric determination. In this particular instance two things may happen, namely ... 

In iodometric determinations the pharmaceutical substance oxidizes KI in an acidic medium to produce an equivalent quantity of iodine that may be assayed by titration with a standard solution of sodium thiosulphate. 

Chlorine, positive , iodometric determination of, 48, 5 reaction with 2-butyne, 46, 34 a-Chloroacetamide, reaction with oxalyl chloride to give a-chloroacetyl isocyanate, 46, 16... 

By definition POV is the number of miliequivalents of active oxygen per kilogram of sample" , or in some cases the number of micrograms of active oxygen in one gram of sample, capable of oxidizing iodide to iodine" °°. Many of the methods described in Section V for determination of hydroperoxide classes or individual compounds can also be applied for determination of POV, as total hydroperoxides. The iodometric determination of hydroperoxides in lipids and proteins has been reviewed . 

The iodometric determination of hydroperoxides in lipids and proteins has been reviewed . Although the standard AOCS iodometric method for POV accounts for the peroxides present in the sample, interference is possible from the action of air that causes liberation of additional I2, or other moieties present in solution that may react with I2. Thus, alternative methods have been proposed for the determination of this important parameter, such as the analytical kits in Table 2, other spectrocolorimetric... 

Formation of polymeric peroxycarboxylic acids of variously grafted celluloses, such as 228 and 229, where the thick line represents the main cellulose strand, and assessment of their thermal stability by following their decomposition at various temperatures is based on iodometric determination of the peracids . 

Also, di-f-butyl peroxalate (233) can be synthesized according to equation 81 from the analogous reagents. The iodometric determination of 233 can be carried out by letting iodide react for about 30 min. The titration shows only half of the expected equivalents. The mechanism of this reduction involves a slow step leading to an anionic intermediate (234), which decomposes in a fast step before the second reduction can be accomplished, as shown in equation 82 . An explosion has been reported when handling wet crystals of 233, which seem to be extremely friction-sensitive . 

Titrimetric Methods. Frequently, the reduction of gold solutions leads to finely divided precipitates which are difficult to recover quantitatively. In such cases, the reduction of Au(III) to Au(0) by, eg, hydroquinone, can be followed potentiometrically (49). The end point in such titrations also can be determined with indicators such as benzidine (50) or 0-anisidine (51). Alternatively, the reduction can be effected with excess hydroquinone which is then back-titrated with Ce(IV) (52). Iodometric determination of Au(III) also is useful (53). 

Siggia, S. and Edsberg, R. L. (1948) Iodometric determination of vinyl alkyl ether, Anal. Chem. 20, 762-763. 

These reactions are used in quantitative analysis for the iodometric determination of copper. 

A simple and rapid method for the iodometric determination of microgram amounts of chromium(ni) in organic chelates is based on the oxidation of chromium(III) with periodate at pH 3.2, removal of the umeacted periodate by masking with molybdate and subsequent iodometric determination of the liberated iodate . Iodometric titration was also used for determination of the effective isoascorbate (see 2) concentration in fermentation processes . The content of calcium ascorbate can be determined with high sensitivity by complexometric titration with edta, which is superior to iodometry. The purity of /3 -diketonate complexes of Al, Ga, In and Ni was determined by complexometric titration with edta at pH 5.5-3, with RSD < 0.01 for determining 5-30% metal ion. Good analytical results were obtained by a similar procedure for the metal content of 15 lanthanide organic complexes. ... 

Russian workers have prepared for pharmacological studies simple carbamates of trachelanthamidine (68) by treatment with the appropriate isocyanate. Some cholinesterase inhibitors based on the standard decamethonium model have been prepared. Decamethylene bistrachelanthamine dibromide (69) showed marked curare-like activity in cats and rabbits. New procedures for the iodometric determination of platyphylline bitartrate and for the colorimetric determination of trichodesmine and incanine in the organs of poisoned animals have been described. 

The reaction mechanism in the iodometric determination of phenoxymethyl penicillin has been studied recently" by Glombitza and Pallenbach93,... 

Immediately After y-Exposure. Exposure of unstabilized PP film to 2-3 Mrad. of y-irradiation in air results in oxidation which is readily observed in the IR (Figure 1) at 3400 (-0H species), 1715 (carboxyl species) and 1200 cm-1. The origin of the latter absorption is not well established, but may be indicative of C-O-C-and C-0-0 linkages. From iodometric determinations, the hydroperoxide (-00H) groups dominated at the lower dose rate, whereas alcohol -OH was much more important at the higher dose rate. 

Iodohexane, 31, 67 Ji-Iodomandelic acid, 35,14 Iodometric determination of active oxygen, 34, 92... 

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