Determination of hypophosphite and phosphite by their reduction of iodine,iodate, or periodate and mercury(I) titration of iodide

A new potentiometric method is adopted for the accurate determination of hypophosphite and phosphite alone or in their mixtures using alcoholic iodine, iodate, and periodate. Hg(I) was used as titrant for the produced iodide in case of using alcoholic iodine as oxidant or for the excess added iodide in case of iodate and periodate as oxidants using silver amalgam as the indicatior electrode. The potential breaks which average 300 mV per 0.1 ml of titrant were sharp enough for precise determination of endpoints, and hence the high accuracy of the present method.     

The acid-base properties of solochrome violet R. S.

Summary The acid base properties of solochrome violet R.S. has been studied with the object of testing its use as an acid base indicator or as a colorimetric reagent. The pk values of 4.35, 7.4, and 9.45 corresponding to the three steps of ionisation of the free acid were evaluated by the aid of the relation between log (acid)/(salt) and ph values obtained during the course of the potentiometric titration of the free acid with a free base. The dye has proved to be a suitable indicator in titrating some mineral and organic acids as well as a colorimetric reagent for the microdetermination of vanadium.     

Fast Grey R.A. as a new colorimetric reagent

Summary Fast Grey R.A. dye can be used for the colorimetric microdetermination of vanadium in the limits of 0.01 to 1 ppm with a sensitive photometer and 0.05 to 8 ppm with a Beckman instrument, at 560 m. A large number of cations and anions up to 10 fold the vanadium amount do not interfere with its determination. Interference due to ferric iron up to an average of 40 fold or copper up to 2 fold the vanadium concentration is simply eliminated by reduction with ascorbic acid and heating in the case of iron or by the same treatment and the addition of ammonium thiocyanate solution in the case of copper.Part II: See Z. analyt. Chem. 158, 103 (1957).     

Extraction of neodymium and europium by bis-(2-ethylhexyl) phosphoric acid from aqueous diamine solutions

The extraction of Nd³⁺ and Eu³⁺ from aqueous media containing selected diamine ligands by HDEHP solution in benzene has been investigated. It is found that the presence of the diamine in the aqueous phase enhances the extraction of both Nd³⁺ and Eu³ in the organic phase. The possible explanation for this behaviour is presented and a mechanism based on extraction of an adduct of the type MH₃(DEHP)₆. B is found to be the most probable.     

Über Pterinchemie. 68 Mitteilung [1]. Regiospezifische Deuterierungen von Folsäure

Regiospecific deuteriation of folic acid Introduction of a nitroso function at the N (10)-position of folic acid activates the C(9)-hydrogen atoms in such a way, that the exchange of H with D at this position, in NaOD-solution, is extremely facilitated. This fact is utilized in the synthesis of 9,9-dideuterio-folic acid (IV), 7,9,9-trideuterio-folic acid (VII) and 7-deuterio-folic acid (IX). These three products are necessary for the ¹H-NMR.-spectroscopical determination of the conformation of 5,6,7,8-tetrahydrofolic acid and its derivatives.     

Application of Fast Grey RA to the spectrophotometric determination of copper in liver of Egyptian camels

The ortho-orthohydroxyazo dye 15690-Solochromate Fast Grey RA, CI mordant Black 19 (reddish navy-blue black) has been used as a reagent for the spectrophotometric determination of copper in liver of Egyptian camels. To determine copper digest, 1-g dry liver samples with 5 ml of each of 50% v/v sulfuric and concentrated nitric followed by 3 ml hydrogen peroxide, get rid of excess acid by repeated evaporation and washing, transfer quantitatively to 100 ml flask, make with water up to volume, to 1 ml add 2 ml 0.05 N nitric, 2 ml 0.2 M ascorbic acid, 3 ml 0.005% FG make up with water to 10 ml. Measure extinction at 555 mμ. Such a procedure gave satisfactory results as compared to the DEDTC procedure and a recovery of 98.8%.     

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