Potassium iodide, effect

Iodide ion, a moderately effective reducing agent, is used extensively for the deterrnination of oxidants. In such appHcations, the iodine Hberated by reaction between the analyte and the unmeasured excess of potassium iodide is ordinarily titrated with a standard solution of sodium thiosulfate. The reaction is as foHows ... 

The iodate is a poison potassium iodide, however, is used in foodstuffs. Thus the iodate must be completely removed frequently by a final reduction with carbon. After re-solution in water, further purification is carried out before recrystallization. Iron, barium, carbonate, and hydrogen sulfide are used to effect precipitation of sulfates and heavy metals. 

PuUy hydroly2ed poly(vinyl alcohol) and iodine form a complex that exhibits a characteristic blue color similar to that formed by iodine and starch (171—173). The color of the complex can be enhanced by the addition of boric acid to the solution consisting of iodine and potassium iodide. This affords a good calorimetric method for the deterrnination of poly(vinyl alcohol). Color intensity of the complex is effected by molecular weight, degree of... 

Potassium Iodide. When potassium iodide [7681-11-0] is adrninistered orally for several (6—8) weeks, a therapeutic effect may be obtained ia the subcutaneous form of sporotrichosis. Amphotericin B is used iatravenously to treat systemic sporotrichosis. The KI dosage is usually a saturated solution ia water (1 g/mL). The usual oral dose is 30 mg/kg/d. Children should receive five droplets, three times a day (after meals) the dose may be iacreased to 15—20 droplets. Side effects iaclude digestive disorders, swelling of the saUvary glands, and lacrimation. Thyroid function tests may be disturbed. 

In this reaction, iodine is liberated from a solution of potassium iodide. This reaction can be used to assess the amount of ozone in either air or water. For determination in air or oxygen, a measured volume of gas is drawn through a wash bottle containing potassium iodide solution. Upon lowering the pH with acid, titration is effected with sodium thiosulfate, using a starch solution as an indicator. There is a similar procedure for determining ozone in water. 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Cucumber cotyledons were inoculated with purified tobacco mosaic virus (TMV) 20 to 24 hours before vacuum infiltration with different concentrations of crude water extracts of plant leaves (4). After 7 days, inoculated leaves were harvested and stored 24 hours in the dark in a moist chamber to remove excess starch. Starch lesions were counted after clearing with alcohol and staining with an iodine-potassium iodide-lactic acid mixture. The inhibitory effects of various extracts were demonstrated by comparing lesion counts of treated cotyledons to counts on control cotyledons. 

A positive iodinating species was postulated to account for the kinetics and isotope effect observed in the iodination of some amines by iodine in aqueous potassium iodide (in some cases in the presence of acetate, lactate, or phosphate ion). The isotope effects (kH/kD values in parenthesis) for these compounds studied were 2,4,6-trideutero-m-dimethylaminobenzenesulphonate ion, 25 °C (1.0) 2,4,6-trideutero-m-dimethyIbenzoate ion, 30 °C (1.4) 2,4,6-trideutero-dimethylaniline, 30 °C, lactate (3.0) 2,4,6-trideuteromethylaniline, 25 °C, acetate (3.2) 2,4,6-trideuteroaniline, 25 °C (3.5), phosphate (4.0) 2,4,6-trideutero-metanilate ion, 35 °C (2.0) 2,4,6-trideutero-m-aminobenzoate ion, 30 °C (4.8), phosphate (3.0) 2,6-dideutero-l-dimethylaminobenzene-4-sulphonate ion, 25 °C, phosphate (1.0) 4-deutero-l-dimethylaminobenzene-3-sulphonate ion, 25 °C, phosphate (1.0). The kinetics of these reactions was given by... 

There is an additive bone marrow depression when methimazole or propylthiouracil is administered with otiier bone marrow depressants, such as the antineo-plastic drugs, or witii radiation therapy. When methimazole is administered with digitalis, there is an increased effectiveness of the digitalis and increased risk of toxicity. There is an additive effect of propylthiouracil when the drug is administered with lithium, potassium iodide, or sodium iodide When iodine products are administered with litiiium products, synergistic hypotiiyroid activity is likely to occur. 

Aravamudan and Venkappayya75 oxidized dimethyl sulphoxide in acetate buffer of pH 4 to 4.5 and with a reaction time of only 1 min. They then added potassium iodide and acid and titrated with thiosulphate the iodine liberated by unused reagent. They reported that cerium(IV) and Cr(VI) were much less effective oxidizing reagents for the sulphoxide. A very similar procedure was used by Rangaswama and Mahadevappa76 to determine dimethyl sulphoxide and numerous other compounds with chloramine B. 

Finally, an accident involved an active carbon filter, which contained potassium iodide and through which gas containing ozone was passing. The detonation of the filter was explained by ozone oxidising iodide into iodate and by the iodate interacting to produce an explosion with the active carbon (see the effect of iodates on metalloids above). 

Large doses of iodide inhibit the synthesis and release of thyroid hormones. Serum T4 levels may be reduced within 24 hours, and the effects may last for 2 to 3 weeks. Iodides are used most commonly in Graves disease patients prior to surgery and to quickly reduce hormone release in patients with thyroid storm. Potassium iodide is administered either as a saturated solution (SSKI) that contains 38 mg iodide per drop or as Lugol s solution, which contains 6.3 mg iodide per drop. The typical starting dose is 120 to 400 mg/day. Iodide therapy should start 7 to 14 days prior to surgery. Iodide should not be... 

Weissler A, Herbert Cooper W, Snyder Stuart (1950) Chemical effects of ultrasonic waves oxidation of potassium iodide solution by carbon tetrachloride. J Am Chem Soc 72 1769-1775... 

Procedure 10% aqueous solution of potassium iodide, KI, when exposed to sunlight, liberated I2 due to the photolytic decomposition and gave blue colour with freshly prepared starch solution. The intensity of blue coloured complex with the starch increased many fold when the same solution was kept in the ultrasonic cleaning bath. As an extension of the experiment, the photochemical decomposition of KI could be seen to be increasing in the presence of a photocatalyst, Ti02, showing an additive effect of sonication and photocatalysis (sono-photocatalysis) However, the addition of different rare earth ions affect the process differently due to the different number of electrons in their valence shells. 

A UK standard official method [62] has been published for the spectropho-tometric determination of arsenic in sea water. The determination is effected by conversion to arsine using sodium borohydride which is added slowly to the acidified samples by a peristaltic pump. The liberated arsine is trapped in an iodine/potassium iodide solution and the resultant arsenate determined spectrophotometically as the arsenomolybdenum blue complex at 866 nm. The method is applicable down to 0.19 p,g arsenic. 

The optimal reaction conditions for the generation of the hydrides can be quite different for the various elements. The type of acid and its concentration in the sample solution often have a marked effect on sensitivity. Additional complications arise because many of the hydrideforming elements exist in two oxidation states which are not equally amenable to borohydride reduction. For example, potassium iodide is often used to pre-reduce AsV and SbV to the 3+ oxidation state for maximum sensitivity, but this can also cause reduction of Se IV to elemental selenium from which no hydride is formed. For this and other reasons Thompson et al. [132] found it necessary to develop a separate procedure for the determination of selenium in soils and sediments although arsenic, antimony and bismuth could be determined simultaneously [133]. A method for simultaneous determination of As III, Sb III and Se IV has been reported in which the problem of reduction of Se IV to Se O by potassium iodide was circumvented by adding the potassium iodide after the addition of sodium borohydride [134], Goulden et al. [123] have reported the simultaneous determination of arsenic, antimony, selenium, tin and bismuth, but it appears that in this case the generation of arsine and stibene occurs from the 5+ oxidation state. 

Potassium iodate is a fairly strong oxidizing agent that may be used in the assay of a number of pharmaceutical substances, for instance benzalkonium chloride, cetrimide, hydralazine hydrochloride, potassium iodide, phenylhydrazine hydrochloride, semicarbazide hydrochloride and the like. Under appropriate experimental parameters the iodate reacts quantitatively with both iodides and iodine. It is, however, interesting to observe here that the iodate titrations may be carried out effectively in the presence of saturated organic acids, alcohol and a host of other organic substances. 

From the above one might be tempted to attribute ultrasonically enhanced chemical reactivity mainly to the mechanical effects of sonication. However this cannot be the whole reason for the effect of ultrasound on reactivity because there are a variety of homogeneous reactions which are also affected by ultrasonic irradiation. How, for example, can we explain the way in which power ultrasound can cause the emission of light from sonicated water (sonoluminescence), the fragmentation of liquid alkanes, the liberation of iodine from aqueous potassium iodide or the acceleration of homogeneous solvolysis reactions ... 

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