The analysis of solutions containing mixtures of linear sodium phosphates

A new method for analysis of sodium ortho-, pyro-, and triphosphate is reported. This procedure consists of the measurement of three values which permit a simultaneous solution of three independent equations, yielding the relative amounts of linear phosphates present in the mixture. The measured quantities were: 1) pyrophosphate, gravimetrically determined as zinc pyrophosphate, reprecipitated at 19° and at a pH of 4.0 – 4.5, 2) silver phosphate, determined by a conductance titration at 12°, of standardized silver nitrate solution, and 3) total phosphate, determined after complete hydrolysis to orthophosphate in hot acid solution.     

Determination of quinol in volumetric analysis

Summary A short review is given of the literature concerning volumetric determination of quinol. Comparison of various titration procedures and their possible application shows that the cerimetric determination must be preferred for the standardization of pure quinol solutions; when determining the amount of quinol in mixtures, however, one must usually be content with a titration procedure using dichromate, vanadate, ferricyanide and zinc or bromate-bromide, which each have their special applications. In these cases it is recommended to compare the results of the method chosen with the results of a cerimetric determination using a pure quinol solution.

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Zusammenfassung Es wird ein kurzer Überblick über die Möglichkeiten zur volumetrischen Hydrochinonbestimmung gegeben. Ein Vergleich verschiedener Verfahren zeigt, daß zur Titerstellung reiner Hydrochinonlösungen die Cerimetrie am besten geeignet ist. Zur Hydrochinonbestimmung in Mischungen muß jedoch eine Titration mit Dichromat, Vanadat, Hexacyanoferrat(III) und Zink oder Bromat-Bromid verwendet werden, von denen jede ihre besondere Anwendungsmöglichkeiten besitzt. In diesen Fällen ist es empfehlenswert, die erhaltenen Werte mit denen einer cerimetrischen Bestimmung an einer reinen Hydrochinonlösung zu vergleichen.

     

The micro volumetric determination of uranium with application to bismuth base alloy analysis

The macro volumetric method for the determination of uranium by titration against standard ceric sulphate after reduction on a lead column has been successfully applied on the micro scale Microgram amounts of uranium can be determined by this method, the lowest amount determinable being about 1 microgram. The procedure is accurate to within ±1% at the 100 μg level of uranium Although bismuth and iron cause difficulty, there is no interference from zirconium or thorium.This method for uranium has been applied to the analysis of bismuth base alloys containing uranium in concentrations from 0.005 to 0.1% by weight.     

Diphenyl carbazone as an internal indicator in volumetric analysis

Summary A method for the volumetric determination of calcium using diphenyl carbazone as indicator has been described. Calcium is precipitated by excess sodium oxalate, the excess oxalate being determined by standard lead nitrate. A study of the possible interferences of barium and magnesium in the above determination is undertaken and it is shown that the above procedure is applicable to the determination of calcium in the presence of magnesium and barium.Sincere thanks of the authors are due to Professor G. B. Singh for providing the necessary facilities during the course of the above investigation.     

The differential enthalpimetric determination of phosphates in fertilisers

The phosphate contents of fertilisers of various types have been determined enthalpimetrically using a measure of the heat of precipitation of zirconium phosphate in a strongly acidic medium, for the calculation. The use of a sulphuric acid medium obviates the necessity for removal of calcium ions; the apparatus compensates for heats of mixing of the reagents. The precision for this rapid method is 2.5 % at the mg level.

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Zusammenfassung Der Phosphatgehalt verschiedener Typen von Kunstdünger wurde enthalpimetrisch bestimmt, wobei zur Berechnung die Messung der Fällungswärme von Zirkoniumphosphat in stark saurem Medium eingesetzt wurde. Bei Einsatz eines schwefelsauren Mediums erübrigt sich die Entfernung der Calcium-Ionen; das Gerät kompensiert die Mischungswärmen der Reagenzien. Die Genauigkeit dieser Schnellmethode liegt im mg-Bereich bei 2.5%.

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Résumé On a determiné par enthalpimétrie la teneur en phosphate de divers types d'engrais chimiques, en utilisant pour le calcul la mesure de la chaleur de précipitation du phosphate de zirconium en milieu fortement acide. En milieu acide sulfurique, il n'est pas nécessaire d'éliminer les ions calcium; l'appareil contrebalance la chaleur de mélange des réactifs. La précision de cette méthode rapide est de 2.5 % à l'échelle du mg.

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, . , . . 2,5% .

     

Nitroxyalkyl phosphates

Russian Chemical Bulletin -     

Biology-enabling inositol phosphates, phosphatidylinositol phosphates and derivatives

This review highlights inositol polyphosphate- and phosphatidylinositol-based small molecule probes that have advanced our understanding of intracellular signalling.     

The volumetric determination of nitrite with chloramine T

Nitrite may be determined by oxidation with chloramine T, reaction of the excess of chloramine T with excess KI, and titration of I(2) formed, with thiosulphate. The reproducibility and some interferences are discussed.     

Scheme and studies of reference materials for volumetric analysis in Japan

This paper describes the history and scheme of reference materials and standard solutions for titrimetry in Japan. Titrimetry is one of the most fundamental and precise methods for determination of a constituent, based on the effective purity of reference materials in stoichiometric analysis. It has wide-ranging applications based on titrimetric reactions such as neutralization, redox, chelatometric, and precipitation titration processes, which are used in various analytical fields all over the world. Japanese Industrial Standards (JIS) have played an important role in establishing a stable supply of reference materials for titrimetry since the 1950s. There are several reports of preparations and their determination, including coulometric studies, in order to establish highly reliable reference materials. This paper briefly reviews the schemes and studies of standardization through the provision of reference materials and standard solutions based on JIS, and several applications in other standards. Presented at Berm-11, October 2007, Tsukuba, Japan.     

Thermal analysis of the interaction of phosphorite with condensed phosphates of calcium

The thermal reactions between Maardu (Estonia) phosphorite and acidic phosphates were investigated. TG, DTG and DTA of mixtures with H₃PO₄, Ca(H₂PO₄)₂ · H₂O, Ca₂P₂O₇ and [Ca(PO₃)₂]_n in different molar ratios showed a maximum mass loss when the CaO P₂O₅ value was 2. The main temperature ranges of the mass losses were determined. The probable reactions relating to the mass losses are given on the basis of the thermal curves and IR spectra.

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Zusammenfassung Die thermische Reaktion zwischen Phosphorit aus Maardu (Estnien) und sauren Phosphaten wurde untersucht. TG, DTG und DTA von Gemischen mit H₃PO₄, Ca(H₂PO₄)₂ · H₂O, Ca₂P₂O₇ und [Ca(PO₃)₂]_n in verschiedenen molaren VerhÄltnissen zeigten den grö\ten Massenverlust bei dem VerhÄltnis von CaO P₂O₅=2. Die wichtigsten Temperaturbereiche der Massenverluste wurden bestimmt. Die den Massenverlusten zugeordneten wahrscheinlichen Reaktionen werden aus den erhaltenen thermischen Kurven und IR Spektren ermittelt.

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Résumé Etude de l'effet thermique lié à la réaction entre la phosphorite de Maardu (Estonie) et les hydrogénophosphates. Etude par TG, TGD et ATD de mélanges de H₃PO₄ avec Ca(H₂PO₄)₂ · 2 H₂O, Ca₂P₂O₇ et [Ca(PO₃)₂]_n réalisés avec différents rapports molaires; mise en évidence d'une perte de masse maximale pour le rapport CaO P₂O₅ égal à deux. Détermination des principaux domaines de température où s'effectuent les pertes de masse. On donne les réactions probables correspondant aux pertes de masse en s'appuyant sur les courbes d'analyse thermique et spectres infrarouges.

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() . TG, DTG DTA H₃PO₄, Cc(H₂PO₄)₂. H₂O, Ca₂P₂O₇ [Ca(PO₃)₂] _n , CaOP₂O₅ 2. . , .

     

The volumetric determination of bismuth as bismuth-hydrogen iodide-oxin

Summary A critical study has been made ofR. Berg andO. Wurm's method for the determination of bismuth as HBiJ₄ oxin. The indirect method in which the excess of iodide is back titrated is recommended particularly in the determination of very small amounts of bismuth. Low results are obtained when the chloride concentration is greater than about 0,1N in the final mixture.

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Zusammenfassung Die Methode vonR. Berg undO. Wurm zur Wismutbestimmung als HBiJ₄-Oxin wird kritisch untersucht. Die indirekte Methode, die eine Rücktitration des Jodüberschusses beinhaltet, wird besonders zur Bestimmung sehr kleiner Wismutmengen empfohlen. Ist die Chloridkonzentration in der Endlösung größer als etwa 0,1 n, so erhält man zu niedrige Resultate.

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Résumé Les auteurs donnent une critique de la méthode deR. Berg etO. Wurm pour le dosage du bismuth comme HBiJ₄-oxine. Il recommande de n'utiliser la méthode indirecte de retitrer l'excès de iode que pour le dosage de très petites quantités de bismuth; si la concentration des chlorures dans la solution est plus grande qu'à peu près 0,1 n, les résultats obtenus sont trop bas.

     

Model analysis of zeolite-like phosphates and their adsorption complexes with water molecules

Molecular models of borophosphates, aluminophosphates, and silicon-containing derivatives of these phosphates have been subjected to quantum-chemical analysis in the MNDO approximation. Bonding energies of these compounds with water molecules have been calculated. Incorporation of silicon atoms into the phosphate matrix increases its hydrophilicity and acidity.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 30, No. 4, pp. 223–226, July–August, 1994.     

蜂王浆中磷酸腺苷的提取及超高效液相色谱分析

比较了高氯酸提取、热水提取和热硫酸镁溶液提取3种提取方式对蜂王浆中磷酸腺苷三磷酸腺苷(ATP)、二磷酸腺苷(ADP)和单磷酸腺苷(AMP)的提取效果,发现在低温(低于4 ℃)下以5%高氯酸的提取效果最佳。采用超高效液相色谱-紫外检测法分析蜂王浆中的ATP, ADP和AMP的含量。以BEH Shield RP18柱(100 mm×2.1 mm,1.7 μm)为分析柱,以50 mmol/L的磷酸二氢铵(pH 6.5)和乙腈为流动相进行梯度洗脱,3种磷酸腺苷在4 min内实现了较好的分离。以加标王浆样品作添加回收率测定,ATP, ADP和AMP的回收率分别为84.1%～94.3%,86.2%～93.7%和91.0%～104.3%,相对标准偏差均小于10%。方法已被用于一些实际样品的分析,以了解ATP, ADP和AMP在蜂王浆样品中的分布情况。     

Properties of riboflavin phosphates

The u.v., visible, and i.r. spectra, the extinction coefficients, fluorescence, and dissociation constants of pure riboflavin-5'-phosphate and riboflavin-5'-pyrophosphate are studied and discussed.     

Dichloromethyleneamides of dialkyl phosphates

Summary Dichloromethyleneamide dialkyl phosphates (AlkO)₂P(O)N=CCl₂ (alkyl: C₂H₅,C₃H₇, i-C₃H₇, C₄H₉, i-C₄H₉) were obtained by reaction between chlorine and the corresponding isothiocyanatophosphate esters. The dichlorides obtained reacted vigorously with amines, alcohols, and alcoholates.Translated from Izvestiya Akademii Nauk SSR, Seriya Khimicheskaya, No. 5, pp. 932–933, May, 1964     

Copper-substituted tricalcium phosphates

Copper-substituted tricalcium phosphates (CuTCP) with different copper contents were developed using precipitation of copper-containing amorphous calcium phosphates (ACP) from salt solutions followed by heat treatment. Porous CuTCP ceramic was obtained using negative replicas. Using a set of investigation methods (powder X-ray diffraction, IR spectroscopy, ESR spectroscopy, and scanning electron microscopy), all copper-substituted tricalcium phosphates were found to have the whitlockite structure with copper incorporated in TCP in the 2+ oxidation state. The resulting material is promising for the use in regenerative medicine owing to higher solubility in body fluids compared with TCP and combination of bactericidal properties and the lack of cytotoxicity.     

The mechanism of the acid-catalyzed decomposition of the farnesyl phosphates

The rates and (in some cases) products of the acid-catalyzed decomposition of (Z,E)- and (E,E)-farnesyl phosphate, (Z,E)- and (E,E) - 1,1 - dideutereofarnesyl phosphate, (Z)- and (E) - 6,7,10,11 - tetrahydrofarnesyl phosphate, and t-butyl phosphate have been studied in an attempt to determine whether (Z,E)-farnesyl phosphate ionizes with intramolecular assistance from the C-6/C-7 double bond or via an unassisted process leading to a simple allylic cation. Data in support of both possibilities are adduced, but it is concluded, primarily on the basis of the secondary deuterium kinetic isotope effects, that the ionization involves little, if any, assistance from the double bond.