Spectrophotometric determination of rhenium using 2-pyridyl thiourea

The reagent 2-pyridyl thiourea produces a reddish brown complex with rhenium in hydrochloric acid medium in the presence of tin(II) chloride. The complex shows absorption maxima at 405 nm, obeys Beer's law for a range of 1–16 ppm of rhenium. The sensitivity and molar absorptivity is found to be 0.0115g cm^–2 and 1.603×10⁴ 1 mol^–1 cm^–1 respectively showing an improvement over other sulphur-nitrogen bearing ligands. Composition found by Job's and mole ratio method, indicates that the complex contains metal and reagent in the ratio 12. Stability constant and stepwise formation constants of the complex have been evaluated by Harvey-Manning's method (logK _overall=8.825), Leden's method (logK _overall=8.3096), Rossotti-Rossotti's method (logK _overall=8.653) and Yatsimirskii's method (logK _overall=8.740). The relative error per 1% absolute photometric error is found to be 2.7%.     

Application of ternary complexes in pharmaceutical analysis

Summary The formation of a ternary complex of iron(III) with isoniazid-2-hydroxybenzaldehyde hydrazone(INSH) in a cetyltrimethylammonium bromide(CTAB) micellar medium, leads to a simple, sensitive and accurate spectrophotometric microdetermination of the iron(III), either in pure aqueous solutions or, particularly, in various anti-anaemic formulations. The apparent molar absorptivity of this complex and Sandell's sensitivity at 386 nm were 2.08×10⁴ lmol^–1 cm^–1 and 2.68 ngcm^–2, respectively. The calibration graph which was traced according to the regression line equation, A=3.70×10^–1 C+1.09×10^–3 (r=1.0000; n=28), was rectilinear for 100 ppb to 3.0 ppm of iron(III). The accuracy and the precision of the method could be considered as very satisfactory, since the mean CV% was 0.202 in the range 0.5–3.0 g of iron(III) per ml. The results obtained for iron(III) by the new method and by the o-phenanthroline method, were compared statistically by means of the Student t-test and the variance ratio F-test; no significant difference was found.Parts I and II see [6] and [7]     

Determination of antimony in waste water by micelle solubilization spectrophotometry

A simple, sensitive and selective micelle solubilization spectro-photometric method is described for the determination of micro amounts of antimony(III) in waste water with 2-(3,5-dibromo-2-pyri-dylazo)-5-diethylaminophenol (3,5-dibromo-PADAP) as colour reagent and emulsifier OP as solubilizing and sensitizing agent. In 0.15M HCl, antimony forms a blue-green ternary complex with the above-mentioned reagents. The complex exhibits maximum absorption at 630nm, and the value of the apparent molar absorption coefficient is found to be 5.2 × 10⁴1 mol^–1 cm^–1. The complex is stable up to 7 days at room temperature. The system obeys Beer's Law in the range 0–25 g Sb(III) per 10 ml. Most metal ions do not interfere with the determination of antimony.     

Extraction and spectrophotometric determination of nickel based on the formation of a ternary complex with cadion and 1,10-phenanthroline

Summary A sensitive and selective spectrophotometric method has been developed for the determination of nickel, based on the formation of red ternary complex of nickel with cadion and 1,10-phenanthro- line in alkaline solution (0.5N NaOH). The complex is quantitatively extracted by chloroform and exhibits an absorption maximum at 505 nm. Beer's law is obeyed in the concentration range of 0–2.5g of Ni(II)/5 ml chloroform. The Sandell sensitivity and molar absorptivity of the reaction are 0.000587g cm^–2 and 1.0×l0⁵l· mol^–1·cm^–1, respectively. The method has been applied to the determination of nickel in alloy steels, aluminium alloys and soils.

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Extraktion und spektrophotometrische Bestimmung von Nickel mit Cadion und 1,10-Pbenanthrolin als ternärer Komplex

Zusammenfassung Eine empfindliche und selektive Methode zur Bestimmung von Nickel mit Cadion und 1,10-Phenanthrolin wurde ausgearbeitet. Sie beruht auf der Bildung eines roten ternären Komplexes in alkalischer Lösung (0.5N NaOH). Bei 505 nm entspricht die Färbung dem Beerschen Gesetz zwischen 0 und 2,5g Ni(II)/5 ml Chloroform. Der Komplex läßt sich mit Chloroform extrahieren. Die Empfindlichkeit der Reaktion beträgt 0,000587g· cm^–2 und die molare Absorption 1.0×10⁵l·mol^–1·cm^–1. Die Bestimmung von Nickel in Stahl, Aluminiumlegierungen und Böden ergab zufriedenstellende Resultate.

     

Sorption of Cu2+ ions by chitin and chitosan from aqueous solutions. Molecular structure of complexes formed

The sorption of Cu²⁺ ions by chitin and chitosan from aqueous solutions has been investigated, as well as the molecular structure of the complexes formed. The static exchange capacities have been determined, equal to 3.5 and 0.25 mmole/g for chitosan and chitin, respectively, and the partition coefficients (5000 and 70 g/ml). It has been shown that in complex formation a bond with the amino group is formed as the result of the substitution of a proton in the latter. The EPR spectra of these complexes have been obtained and their radiospectroscopic parameters determined (g = 2.334,g = 2.054,A = 0.0156 cm^–1, andB = 0.0028 cm^–1 for chitin, andg = 2.231,g = 2.048,A = 0.0192 cm^–1, andB = 0.0025 cm^–1 for chitosan). For chitosan the ligands are two nitrogen atoms of the amino groups and two oxygen atoms of the hydroxyl groups in the position C³ of adjacent glucosamine rings; for chitin, the oxygen atoms of the acetyl groups take part in addition in the complex formation. The analysis of the radiospectroscopic parameters and their comparison with published data lead to the conclusion that the Cu²⁺ complex with chitosan has a tetragonal symmetry, while the complex with chitin most probably has an octahedral structure.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2305–2311, October, 1992.     

Spectrophotometric and derivative spectrophotometric determination of copper (II) with dithizone in aqueous phase

A Spectrophotometric and derivative Spectrophotometric study of Cu-dithizonate complex in aqueous phase in the presence of Triton X-100, a neutral surfactant, is reported. The system obeys Beer's law between 1.0 × 10^–6–9.0 × 10^–6 mol/l of Cu²⁺; detection limit is 12 ng/ml. The molar absorption coefficient, specific absorptivity and Sandell's sensitivity of the complex are 3.06 × 10⁴ 1 mol^–1 cm^–1, 0.4825 ml g^–1 cm^–1 and 2.1 × 10^–3 g cm^–2, respectively. The conditional stability constant of the 1 2 complex, calculated considering simultaneously existing equilibria, has been found to be 1.73 × 10¹¹ I² mol² (I = 0.07, pH 1.4, temperature = 10 °C). Absorption studies in the derivative mode have been carried out to determine the absorption maximum of the complex and to overcome interference due to the presence of certain metal ions. The method has been validated by determination of copper in beers, wines, human hair, goat liver and fly ash samples.     

IR spectroscopic study of thioacrolein and its photoisomerization to methylthioketene

The molecules of thioacrolein (1) and metylthioketene (3), which are labile under normal conditions, have been studied by the matrix Fourier transform infrared spectroscopy method. Compound1 was obtained by vacuum pyrolysis (1120 K, 10^–4 Torr) of diallyl sulfide. The analysis of its IR spectrum shows that1 exists as a mixture ofs-trans ands-cis conformers. UV irradiation ( > 248 nm) of matrix isolated1 results in a 1,3 hydrogen shift and the formation of3, which is characterized by a strong band of antisymmetric stretching vibrations of the thioketene fragmentvC=C=S at 1777.2 cm^–1. The experimental IR bands of molecules1 and3 were assigned to fundamental modes. The relatively low frequencies of the stretching vibrations of the double bonds (vC=C at 1598.0 cm^–1 andvC=S at 1071.8 cm^–1) and the heightened frequency of the C-C single bond stretching (vC-C 1173.7 cm^–1) in the spectrum of1 indicate appreciable delocalization of the electron density in the conjugated -orbital system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 464–470, March, 1995.     

Application of symmetry coupling coefficients in the evaluation of the electronic spectra of d 7 ions

The optical absorption spectrum of cobalt chloride thiourea has been studied at room and liquid air temperatures. The results have been interpreted using group theoretical methods taking into account all the quartet states and several doublet states. Crystal field, electrostatic, and spin-orbit coupling interactions were included to yield the allowed transitions with the relative transition probabilities. The experimental results were interpreted for the following set of parameters: B = 750cm^–1, C = 3100cm^–1, = 7370cm^–1, = -200 cm^–1, = 500cm^–1, and = 450 cm^–1.     

Spectrophotometric determination of osmium using o-hydroxythiobenzhydrazide

Summary Osmium(VI) forms a violet complex witho-hydroxythiobenzhydrazide in the pH range 5.4–6.4. The complex is readily extractable in chloroform to give a violet solution which can be employed for the photometry of osmium. The extract shows maximal absorption at 540–550 nm and obeys Beer's law over the concentration range 1.44–14.40g Os ml^–1.g amounts of osmium can be determined witho-hydroxythiobenzhydrazide in the presence of considerable amounts of diverse ions commonly associated with the metal using EDTA as the masking agent. However, gold should be removed prior to the determination of osmium with the reagent. The molar extinction coefficient of the complex and the Sandell sensitivity are 1.18×10⁴ l mole^–1 cm^–1 and 0.016g cm^–2 respectively.

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Zusammenfassung Osmium(VI) bildet mit o-Hydroxythiobenzhydrazid zwischen pH 5,4 und 6,4 eine violette Komplexverbindung. Diese läßt sich mit Chloroform gut extrahieren. Die violette Lösung eignet sich für die photometrische Bestimmung des Osmiums, zeigt maximale Absorption bei 540–550 nm und entspricht zwischen 1,44 und 14,40g Os/ml dem Beerschen Gesetz. Mikrogrammengen Osmium können so neben erheblichen Mengen verschiedener anderer Begleitionen nach deren Maskierung mit ÄDTA bestimmt werden. Gold jedoch muß vorher entfernt werden. Der molare Extinktionskoeffizient beträgt 1,18×10⁴ l · Mol^–1 · cm^–1, die Empfindlichkeit nach Sandell 0,016g · cm^–2.

     

Single crystals of regio-selectively substituted cellulose hetero-esters

Lamellar single crystals of some regio-selectively substituted cellulose hetero-esters: cellulose propionate diacetate (CPDA, 2,3-di-O-acetyl-6-O-propionyl cellulose), cellulose acetate dipropionate (CADP, 6-O-acetyl-2,3-di-O-propionyl cellulose), cellulose butyrate diacetate (CBDA, 2,3-di-O-acetyl-6-O-butyryl cellulose) and cellulose acetate dibutyrate (CADB, 6-O-acetyl-2,3-di-O-butyryl cellulose), have been prepared at high temperature in a mixture of dibenzyl ether andn-tetradecane. The CPDA crystals were lozenge-shaped whereas those of CADP, CBDA and CADB had a ribbon morphology. CPDA crystals gave well-resolved electron diffractograms from which the reciprocal lattice parameters a^*=0.807 nm^–1,b ^*=0.400 nm^–1 and ^*=90° could be determined. Systematic absences occurred at every odd reflection along the two orthogonal axesa ^*andb ^*. Thus, the CPDA diffraction pattern is consistent with a p_gg symmetry. For CADP, the electron diffraction pattern is consistent with a p_mg two-dimensional space group withb the unique axis along the ribbon direction. The diagram yields the reciprocal lattice parameters a^* = 0.902 nm^–1,b ^*=0.651 nm^–1 and ^*=90°. The CBDA electron diffractogram yields the following cell parameters and two-dimensional space group:a ^*=0.482 nm^–1,b ^*=0.659 nm^–1 and ^*=90°, and a p_gg symmetry; and that of CADB:a ^*=0.834 nm^–1,b ^*=0.645 nm^–1 and ^*=90°, and a p_mg symmetry.     

Preparation of soluble ternary heteroazo dye complexes for the spectrophotometric determination of trace uranium(VI)

The complexing ability of typical pyridylazo, quinolylazo and thiazolylazo dyes with uranium(VI) in aqueous ethanol media are investigated in the presence and absence of aromatic carboxylic acid. Uranium(VI) forms solubilized ternary complexes with PAN, PAR, TAM, 5-Br-PADAP, 3,5-diBr-PADAP and QADAP in 48% ethanol solution containing sufficient amounts of sulfosalicylic acid and triethanolamine buffer (pH 7.8). Aromatic carboxylic acids contribute to expel the coordinated water molecules from the uranium (VI) moiety and their chelating effects have been explained by ternary complex formation. An increase in molar absorptivity and no shift in the wavelength of maximum absorbance are observed for all uranium(VI) complexes investigated. The 11 stoichiometry of uranuim(VI) and heteroazo dye in the binary complex does not change through ternary complex formation. The molar absorptivity of the uranium(VI)-3,5-diBr-PADAP-sulfosalicylic acid ternary complex at 595 nm is 8.4×10⁴l mol^–1 cm^–1 and Beer's law is valid up to 2.5gmg ml^–1 of uranium(VI). The interferences due to coexisting metal ions can be effectively masked by addition of CyDTA or Ca-CyDTA.     

Synthesis,Spectral Properties,and Crystal Structure of {Methoxo[4-phenylbutane-2,4-dione(p-nitrobenzoyl) hydrazonato(2-)]oxovanadium(V)}

The hydrazino complex {methoxo[4-phenylbutane-2,4-dione(p-nitrobenzoyl)hydrazonato(2-)]oxovanadium(V)}, VO(p-NO₂bhbzac)OCH₃, (1), has been prepared by the direct reaction of bis(benzoylacetonato) oxovanadium(IV), VO(bza)₂, with p-NO₂-C₆H₄C(O)NHNH₂, p-NO₂bh, in CH₃OH. The resulting compound contains benzoylacetone-(p-NO₂)benzoyl hydrazone as tridentate Schiff base-type ligand and OCH₃ group as Lewis base, both ligated to vanadium. The crystals are orthorhombic, with Z = 8, space group Pbca, a = 11.699(5) Å, b = 14.035(5) Å, c = 22.564(5) Å, R1 = 0.0756 and wR2 = 0.1302. The crystal structure demonstrated the square-pyramidal geometry of the VO_oxo(ONO)O coordination sphere with the oxo ligand at the apical position. The electronic absorption spectra revealed a ligand-to-metal charge-transfer (LMCT) band in the near UV region at _max = 23,700 cm^–1 (B = 5640 dm³ mol^–1 cm^–1) in CH₃CN, _max = 23,420 cm^–1 (B = 5550 dm³ mol^–1 cm^–1) in DMSO, and _max near 26,950 (sh) cm^–1 (B = 10,550 dm³ mol^–1 cm^–1) in CH₂Cl₂. The FT-IR spectra of (1) show the characteristic strong (V = O) stretching vibration at 993 cm^–1 and support the view that the oxovanadium complex is pentacoordinated and monomeric.     

Extraction spectrophotometric investigation of mixed ligand complex of molybdenum(V) with thiocyanate and 4-acetyl-2-(acetylamino)-5-dimethyl-Δ2-1,3,4-thiadiazole

A sensitive spectrophotometric method is developed for the determination of small amounts of molybdenum based on the extraction of molybdenum-thiocyanate-4-acetyl-2-(acetylamino)-5-dimethyl- ²-1,3,4-thiadiazole complex into chloroform from hydrochloric acid medium which is orange red in colour. The complex has an absorption maximum at 470 nm with a molar absorptivity of 2.01×10⁴l·mole^–1·cm^–1. Beer's law is valid over the concentration range 0.06–2.5 ppm of molybdenum with an optimum concentration range of 0.15–2.2 ppm. The ternary complex is stable for over one week at room temperature. Equilibrium shift method indicates 142 composition for molybdenum-thio-cyanate-4-acetyl-2-(acetylamino)-5-dimethyl- ²-1,3,4-thiadiazole complex. The effects of acidity, reagent concentrations, time, temperature and diverse ions upon the absorbance of the complex are critically assessed. This method has been used successfully for the determination of molybdenum in molybdenum steels.     

Direct and Derivative Spectrophotometric Determination of Thorium with 2,4-dihydroxybenzaldehyde Isonicotinoyl Hydrazone

A simple and sensitive spectrophotometric method is developed for the determination of throium in aqueous medium. The metal ion forms yellow coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 2.0–8.0. The complex shows an absorption maximum at 390 nm. The absorbance of the complex is maximum at pH 5.5 Beer's law is obeyed in the range 0.30–7.00 g/ml of thorium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 2.20· 10⁴ l·mol^–1·cm^–1 and 0.0106 g/cm^–2, respectively. The interference of various ions was studied. The composition of the complex is 1:1 {Th(IV) : 2,4-DHBINH}. The first derivative spectrum of the complex shows a zero cross at 391.2 nm and maximum amplitude at 415 nm. Thus a sensitive derivative spectrophotometric method for the determination of Th(IV) is proposed.     

Magnetic Properties of (C5H6N)5[Fe13O4F24(OCH3)12] · CH3OH · 4H2O

The static magnetic susceptibility of Fe(III) complex [Fe₁₃O₄F₂₄(OCH₃)₁₂]^5– was measured in the temperature range 2–300 K. The structure of the complex consists of four triangular Fe₃ fragments interacting with a central Fe atom. By disregarding weak exchange interactions through F bridges, an analytical solution of the exchange Hamiltonian was obtained with Nf 1.3 × 10¹⁰ levels. This made it possible to perform quantitative interpretation of the temperature dependence of the magnetic susceptibility. The obtained exchange parameters of the best approximation are –2J ₁ = 43 cm^–1, –2J ₂ 30 cm^–1. The ratio J ₂/J ₁ 0.70 suggests that the Fe₁₃ ground state has the spin of the ground state 23/2 or 15/2.     

Determination of Nitrogen in Silicon Carbide by Secondary Ion Mass Spectrometry

The emission of atomic and complex nitrogen ions, which are the main impurity determining the n type conduction of silicon carbide, is investigated. It is shown that, among all the secondary ions of the C _x N and Si _x N kind (x = 0, 1, 2, 3), the ²⁶(CN)^– fragment exhibits the highest ion yield. The use of an ion peak with a specified mass as an analytical signal provides a detection limit for nitrogen in SiC at a level of 10¹⁶ cm^–3. This result is attained in measurements at high mass resolution (M/M = 7500, interference peak ²⁶(¹³C₂)^–).     

Propionyl promazine phosphate as a new reagent for the spectrophotometric determination of rhodium(III)

Summary PPP forms an orange-red coloured complex with rhodium(III) at room temperature (27°) in the presence of sodium acetate-hydrochloric acid buffer of pH 1.0–3.0 containing copper(II) and ascorbic acid. The complex exhibits absorption maximum at 470 nm. Beer's law is valid over the rhodium concentration range 0.1–18g/ml. Sandell's sensitivity of the reaction is 1.8·10^–3 g Rh/cm² and the molar extinction coefficient is 5.68×10³ l·mol^–1cm^–1 at 470 nm. The composition of the complex is 11 and the apparent stability constant of the complex at pH 2.5 and 27° has the logK value of 4.0. The proposed method has been used for the determination of rhodium in thermocouple wires and in synthetic mixtures containing palladium, ruthenium, osmium, uranium or iridium.

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Propionylpromazinphosphat (PPP), ein neues Reagens für die spektrophotometrische Bestimmung von Rhodium(III)

Zusammenfassung PPP bildet mit Rh(III) bei Zimmertemperatur (27°) in Gegenwart von Natriumacetat-Salzsäure (pH 1,0–3,0), Cu(II) und Ascorbinsäure eine orange-rote Komplexverbindung mit einem Absorptionsmaximum bei 470 nm. Das Beersche Gesetz gilt für Konzentrationen von 0,1 bis 18g/ml. Die Empfindlichkeit nach Sandell beträgt 1,8×10^–3 g Rh/cm²; der molare Extinktionskoeffizient bei 470 nm ist 5,68×10³ l·mol^–1·cm^–1. Die Zusammensetzung der Komplexverbindung entspricht dem Verhältnis 11, die scheinbare Stabilitätskonstante bei pH 2,5 und 27° entspricht log K=4,0. Das vorgeschlagene Verfahren diente zur Rh-Bestimmung in Thermoelementdraht sowie in synthetischen Gemischen aus Pd, Ru, Os, U und Ir.

     

Theoretical Study of Chemical Binding of Noble Gas Atom and Transition Metal Complexes: Ng–NiCO, Ng–NiN2, Ng–CoCO (Ng = He–Xe)

Ab initio multireference and coupled cluster methods (MR-SDCI(+Q), CASPT2, CCSD(T)) and density functional theory methods (B3LYP, MPWPW91) have been applied to examine geometrical structures and vibrational frequencies of noble gas (Ng) – transition metal compounds, Ng–NiCO, Ng–NiN₂, and Ng–CoCO (Ng = He, Ne, Ar, Kr, Xe). It is shown that the respective compounds can have a larger binding energy than a typical van der Waals interaction energy. The binding mechanism is explained by a partial electron transfer from a noble gas atom to the low-lying 4s and 3d vacant orbitals of the transition metal atom. Theoretical calculations show that the binding of noble gas atom results in a large shift of the bending frequency: 361.1cm^–1 (NiCO) to 403.5cm^–1 (Ar–NiCO); 308.5cm^–1 (NiN₂) to 354.8cm^–1 (Ar–NiN₂); 373.0cm^–1 (CoCO) to 422.6cm^–1 (Ar–CoCO). The corresponding experimental frequencies determined in solid argon are 409.1cm^–1 (NiCO), 357.0cm^–1 (NiN₂), and 424.9cm^–1 (CoCO), which are much closer to the corresponding frequency of Ar–NiCO, Ar–NiN₂, and Ar–CoCO, respectively.     

Solution equilibria and stability of the complexes of pyridinecarboxylic acids: Complexation reaction of mercury(II) with 2-hydroxynicotinic acid

Summary The solution equilibria of 2-hydroxynicotinic acid (hyna) complexes with mercury(II) have been studied spectrophotometrically in 50% (v/v) ethanol at 20°C and an ionic strength of 0.1mol dm^–3 (NaClO₄). Three mercuric complexes are formed in solution in dependence on the acidity of the medium. The basic characteristics of the different complexes are determined and the analytical aspects of the complexation reaction are demonstrated. A critical investigation has also been presented of the solution equilibria and stability of the mixed complex of mercury(II) withhyna and thiosalicylic acid (tsa). The various complex transitions leading to the formation of the 1 : 1 : 1 Hg(tsa)(hyna) ternary complex in solution are investigated. The non-charged mono-ligand complex Hg(hyna) is used for UV-spectrophotometric determination of mercury atpH 4.5–5 (_max=325nm, =0.8·10⁴lmol^–1cm^–1). The system obeyed Beer's law up to 36.1 µg ml^–1 of Hg(II). The optimum concentration range (Ringbom) is between 6 and 28.5µg ml^–1. Interference caused by a number of ions was masked by the addition of fluoride ions.

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Lösungsgleichgewichte und Stabilitätskonstanten von Komplexen der Pyridincarbonsäuren: Die Komplexierungsreaktion von Quecksilber(II) mit 2-Hydroxynikotinsäure

Zusammenfassung Die Lösungsgleichgewichte von 2-Hydroxynikotinsäure (hyna) mit Hg(II) wurde spektrophotometrisch in 50% (v/v) Ethanol bei 20°C und einer Ionenstärke von 0.1 mol dm^–3 (NaClO₄) untersucht. In Abhängigkeit von der Acidität des Mediums werden drei Quecksilberkomplexe gebildet. Die grundlegenden Charakteristika der Komplexe wurden bestimmt und die analytischen Aspekte aufgezeigt. Die gemischten Komplexe von Hg(II) mithyna und Thiosalicylsäure (tsa), insbesondere die verschiedenen Komplexübergänge zum ternären 1 : 1 : 1 Hg(tsa)(hyna)-Komplex, wurden ebenfalls untersucht. Der ungeladene Monoligandenkomplex Hg(hyna) kann beipH 4.5–5 zur UV-spektroskopischen Quecksilberbestimmung eingesetzt werden (_max=325nm, =0.8·10⁴lmol^–1cm^–1). Das System gehorcht bis zu einer Hg(II)-Konzentration von 36.1µgml^–1 dem Beerschen Gesetz. Der optimale Konzentrationsbereich (Ringbom) liegt zwischen 6 und 28.5µgml^–1. Interferenzen mit einer Reihe anderer Ionen konnten durch Maskierung mit Fluoridionen umgangen werden.

     

Extraction and spectrophotometric determination of uranium(VI) withN-phenylcinnamohydroxamic acid

Uranium(VI) reacts withN-phenylcinnamohydroxamic acid to form an orange-yellow complex in the pH range 5.5–8.5. The orange-yellow complex, having the composition of 12 (metal:ligand), is quantitatively extractable into ethyl acetate. The spectrum of the complex exhibits a maximum absorption at 400 nm with a molar absorptivity of 6500 M^–1·cm^–1. The coloured system obeys Beer's law in the concentration range 2–40g·ml^–1 of uranium(VI). The photometric sensitivity of the colour reaction is 0.037 g·cm^–2 of uranium(VI). Most of the common ions do not interfere and the method has been found to be simple, precise, and free from the rigid control of experimental conditions. The method has been applied to the determination of uranium in synthetic matrices and potable water.