Requirements of iodine

Parenteral nutrition requirements of iodine for adults have not been defined (AMA, 1979 National Advisory Group on Standards and Practice Guidelines for Parenteral Nutrition, 1998) and, as a consequence, most of the total parenteral nutrition products for adults contain no iodine (Kelly, 2002). 

Delange, E (1993). Requirements of iodine in humans. In (eds E Delange, J.T. Dunn and D. Glinoer), Iodine Deficiency in Europe. A Continuing Concern. Plenum Press, New Yrrk, NY, pp. 5-16. 

The recommended daily intake (RDI) for iodine by the WHO (2004) and United States Institute of Medicine (US lOM), for preschool children (90meg), school-age children up to 12 years (120meg), older children and adults (150 meg) is in the same range. The fortification levels are determined as a percentage of the daily requirement in a single or daily serve. In a single serve, the nutritional supplement can provide anywhere between one-third to half the daily requirement of iodine for children. Fortified foods which are to be consumed as such or require minimum reconstitution, provide an opportunity to include known or measured amount of iodine in the diet. 

Iodine has also been used for the disinfection of swimming pool water. The concentration range in which it shows strong bactericidal, virucidal, or amoebicidal action is 5-50 mg/cm, leaving a 0.2-0.6 mg/dm residual iodine concentration. Traces of iodine or iodide ions are found in raw waters. The iodine is an essential trace element for humans. The adult daily requirement of iodine or iodide is 80-150 xg. Iodide content of the drinking water is sometimes checked to decide the amount of supplement needed. The iodide is usually supplied as a table-salt additive in areas where it is needed. As a matter of fact, the determination of iodine or iodide content of water samples is not needed very often. However, the titration or back titration of iodine content is an everyday trick in iodometric analytical procedures. 

Iodine is essential for the formation of the thyroid hormone which is an important regulator of energy metabolism. In iodine deficiency, simple or so-called endemic goiter develops. The human requirement of iodine is... 

The requirement of iodine in adults must be at least equal to the daily amount of hormonal iodine degraded in the peripheral tissues and unrecovered by the thyroid, that is 40 to 100 ig/day... 

Hydrolysis by acids. Place 15 ml. of starch solution in a boiling-tube, add I ml. of cone. HCl, mix well and place in a boiling water-bath for 20 minutes. Cool and add 2 drops of iodine solution to i ml. of the solution no blue coloration is produced. On the remainder, perform tests for glucose in particular show that glucosazone can be formed. Neutralise the excess of acid before carrying out these tests. (Note that a more concentrated acid is required to hydrolyse starch than to hydrolyse the disaccharides, such as sucrose.)... 

Specifications and Standards, Shipping. Commercial iodine has a minimum purity of 99.8%. The Committee of Analytical reagents of the American Chemical Society (67) and the U.S. Pharmacopoeia XXII (68) specify an iodine content not less than 99.8%, a maximum nonvolatile residue of 0.01%, and chlorine—bromine (expressed as chlorine) of 0.005% (ACS) and 0.028% (USP), respectively. In the past these requirements were attained basicaHy only by sublimation, but with processing changes these specifications can be met by direct production of iodine. Previously the impurities of the Chilean product were chiefly water, sulfuric acid, and insoluble materials. Improvements in the production process, and especiaHy in the refining step, aHow the direct obtainment of ACS-type iodine. Also, because of its origin and production process, the Chilean iodine has a chlorine—bromine impurity level of no more than 0.002%. 

The methods in which iodine is used as a catalyst for the reaction between ceric sulfate and nitrite or arsenite (86,87) are capable of determining smaH amounts of iodine. However, these catalytic methods are deHcate and require accurate timing, carefiH temperature control, and special apparatus. 

Account must be taken in design and operation of the requirements for the production and consumption of xenon-135 [14995-12-17, Xe, the daughter of iodine-135 [14834-68-5] Xenon-135 has an enormous thermal neutron cross section, around 2.7 x 10 cm (2.7 x 10 bams). Its reactivity effect is constant when a reactor is operating steadily, but if the reactor shuts down and the neutron flux is reduced, xenon-135 builds up and may prevent immediate restart of the reactor. 

One of the most required methods of determination of iodide-ions in praetiee of ehemieal analysis is photometrie determination of produets of iodination of organie eompounds. The oxidation of iodide to iodine ean be earned out suffieiently seleetively. But in ease of presenee of great abundanee of bromide-ions the seleetive oxidation of iodide-ions is problematie. The variants of determination of iodide-ions with different organie reagents are known, but the absenee of bromide-ions in a system is supposed in most of them. In natural objeets these halides are present simultaneously. 

A. Preparation of Thiocarbonyl Per chloride.—In a 5-I. bottle arranged for cooling by running water is placed 500 g. (6.58 moles) of dry carbon disulfide (Note i) to which 0.5 g. of iodine has been added. Dry chlorine is passed into the cooled carbon disulfide at such a rate that the temperature does not rise above 25°, until the liquid weighs 1770 g. (17.9 moles chlorine) (Note 2). The time required is about forty hours. The product is a deep red liquid, a mixture of impure thiocarbonyl perchloride and sulfur chloride. 

In a 3-I. three-necked flask, fitted with a mechanical stirrer, a reflux condenser, and a separatory funnel, are placed 24.3 g. (i gram atom) of magnesium turnings, 500 cc. of absolute ether, a crystal of iodine, and a 5- to lo-cc. portion of 126.5 g- cc., I mole) of freshly distilled benzyl chloride (b.p. 177-179°). In a few minutes the reaction starts (Note 1) and is controlled if necessary by cooling with a wet towel. The stirrer is started and the balance of the benzyl chloride is run in as fast as the refluxing will permit. The addition requires from one to two hours, and when completed the mixture is refluxed ofi the steam bath with stirring for three hours. With the stirrer stUl running, 182 g. (r mole) of benzophenone (Org. Syn. Coll. Vol. i, 89) dissolved in 500 cc. of absolute ether is added at such a rate that the mixture refluxes rapidly. This requires about twenty minutes and then the reaction mixture is allowed to stand for two hours (Note 2). 

No systematic study of the minimal required amount of lead tetraacetate has been made. In cases where the product of the hypoiodite reaction is an iodo ether (20-hydroxy steroids) the reaction can be interrupted at the iodohydrin stage by reducing the amount of iodine to about 0.5 mole. For the oxidation of iodo ethers to lactones, chromium trioxide-sulfuric acid in acetone has been used. Silver chromate is often added to the reaction mixture but comparable yields are obtained without the addition of silver salt. 

Additions of halogen fluorides to the more electrophilic perfluonnated olefins generally require different conditions Reactions of iodine fluoride, generated in situ from iodine and iodine pentafluoride [62 102 103, /05] or iodine, hydrogen fluoride, and parapeiiodic aud [104], with fluormated olefins (equations 8-10) are especially well studied because the perfluoroalkyl iodide products are useful precursors of surfactants and other fluorochemicals Somewhat higher temperatures are required compared with reactions with hydrocarbon olefins Additions of bromine fluoride, from bromine and bromine trifluonde, to perfluonnated olefins are also known [lOti]... 

A number of dihydroquinolines have been prepared by treating aniline derivatives with acetone or mesityl oxide in the presence of iodine. In these cases aromatization to the fully unsaturated quinoline would require the loss of methane, a process known as the Riehm quinoline synthesis. Such Skraup/Doebner-von Miller-type reactions are often low yielding due to large amounts of competing polymerization. For example, aniline 37 reacts with mesityl oxide to give dihydroquinolines 39, albeit in low yield. ... 

The alkaline solution of thymol is made up to 100 or 200 c.c. as the case may require, using a 5 per cent, soda solution. To 10 c.c. of this solution in a graduated 500 c.c. flask is added a normal iodine solution in shgbt excess, whereupon the thymol is precipitated as a dark reddish-brown iodine compound. In order to ascertain whether a sufficient quantity of iodine has been added, a few drops are transferred into a test tube and a few drops of dilute hydrochloric acid are added. When enou iodine is present, the brown colour of the solution indicates the presence of io ne, otherwise the liquid appears milky by the separation of thymol. If an excess of iodine is present, the solution is slightly acidified with dilute hydrochloric acid and diluted to 500 c.c. From this 100 c.c. are filtered,off, and the excess of iodine determined by titration with normal solution of sodium thiosulphate. For calculation, the number of cubic centimetres required is deducted from the number of cubic centimetres of normal iodine solution added and the resultant figure multiplied by 5, which gives the number of cubia centimetres of iodine required by the thymol. 

The amount of sodium hypochlorite in a bleach solution can be determined by using a given volume of bleach to oxidize excess iodide ion to iodine CIO- is reduced to Cl-. The amount of iodine produced by the redox reaction is determined by titration with sodium thiosulfate, Na2S203 I2 is reduced to I-. The sodium thiosulfate is oxidized to sodium tetrathionate, Na2S406. In this analysis, potassium iodide was added in excess to 5.00 ml of bleach d = 1.00 g/cm3). If 25.00 mL of 0.0700 MNa2S203 was required to reduce all the iodine produced by the bleach back to iodide, what is the mass percent of NaCIO in the bleach ... 

Dilute solutions of iodine, e.g. 0.0001 M, may be titrated similarly with standard thiosulphate. The supporting electrolyte consists of 1.0 M hydrochloric acid and 0.004M potassium iodide. No external e.m.f. is required when an S.C.E. is employed as reference electrode. 

This homogeneous reaction is instantaneous and mixing is limited. As a consequence, at steady state, by measuring the required volume to complete the discoloring of iodine, it is possible to determine the global mixing time very easily. 

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