Spectrophotometric determination of uranium with 5-(2′-carboxyphenyl)azo-8-quinolinol in the non-ionic micellar medium of Triton X-100

Triton X-100, a non-ionic surfactant, has been used to sensitize the reaction of 5-(2-carboxyphenyl)azo-8-quinolinol with uranium in aqueous medium at pH 5.2–6.1 to form a wine red coloured complex. The micellar sensitization results in two and a half-times enhanced molar absorptivity enabling the determination of uranium in rock samples at ppm level, stability of the complex enhanced from 4 hours to at least 72 hours. Extraction of the complex is avoided making the procedure simple, rapid and easy in operation. The molar absorptivity and Sandell's sensitivity of the complex are 1.50·10⁴l·mol^–1·cm^–1 and 15.9 ng·cm^–2, respectively, at _max=568 nm. Beer's law is obeyed over the range 0–3.3 g·ml^–1 of uranium. An amount as low as 0.19 g·ml^–1 of uranium could be determined satisfactorily within a relative standard deviation of ±1.3%. The limits of determination and practical quantitation are 0.29 and 1.80 ppm, respectively. The method was applied to the determination of uranium in soil, stream sediment and rock samples.     

Spectrophotometric determination of beryllium and zirconium using chromotrope-2C

Summary Disodium salt of o-carboxyphenylazo chromotropic acid (chromotrope 2C) has been used for the colorimetric determination of microamounts of beryllium and zirconium. The red-violet complexes show maximum absorption at 580 nm and the colour systems obey Beer's law from 0.025 to 0.375 ppm of beryllium and 2 to 12 ppm of zirconium. The optimum concentration ranges are from 0.125 to 0.375 ppm for beryllium and from 4 to 12 ppm for zirconium, where the percent relative errors per 1% absolute photometric error are, respectively, 3.014 and 3.22. The sensitivity of the reactions per cm² are 0.00067 g Be and 0.027 g Zr. The complexes, with the metal to reagent ratio of 11, have instability constants as 2.836 · 10^–6 for beryllium and 6.026 · 10^–6 for zirconium.     

Extraction,Separation and Spectrophotometric Determination of Bismuth(III) Using 1(4′-Bromophenyl) 4,4,6-Trimethyl (1H,4H)-Pyrimidine-2-Thiol

Abstract

The operating conditions for the spectrophotometric determination of bismuth(III) with 1-(4′-bromophenyl)-4,4,6-trimethyl-(1H,4H)-pyrimidine-2-thiol (4′bromo PTPT) as a ligand by a liquid-liquid extraction technique are presented. In acidic conditions bismuth(III) forms a yellow complex with the ligand which can be extracted in chloroform with an absorption maxima at 410 nm. The molar absorptivity is 1.5×10⁴ l mole^?1 cm^?1 and Sandell's sensitivity is 14.3 ng cm^?2. The difference in the absorbance between the chloroform blank and bismuth(III) sample increases linearly in the concentration range 2-14 ppm at 0.3 M hydrochloric acid. The proposed method is extremely sensitive, rapid, reproducible and has been satisfactorily applied to the determination of trace amounts of bismuth(III) in synthetic mixtures, alloys and pharmaceutical formulations and also provides binary separation of bismuth(III) from selenium, tellurium, lead, antimony, copper and gold. The overall process of extraction and determination takes about 15 to 20 min.     

Test Determination of Lead and Zinc in Water with the Use of Xylenol Orange Immobilized on Silica

Xylenol Orange immobilized on silica as a complex of iron(III) was used for the test determination of lead(II) and zinc(II) in drinking water over concentration ranges of 10–100 and 13–130 g/L, respectively. The maximum distribution coefficients were found to be 7.50 × 10³ mL/g for Pb and 3.75 × 10³ mL/g for Zn. The macro main trace components of water at a level of their maximum permissible concentrations caused no interference. Al(III), Fe(III), and Zn(II) in the presence of NH₄F did not interfere with the determination of Pb(II), whereas lead in the presence of acetate caused no interference with the determination of Zn(II).     

Studies in heavy ion activation analysis

¹¹B induced radioactivation was used to study the trace determination of light elements with 1Z17. 49 nuclear reactions were investigated with ion beam energies ranging from E_lab=10 MeV to E_lab=27 MeV. Five elements were found to be determinable nondestructively, selectively and sensitively: Li, Be, B, Mg and Si. Nuclear interferences have also been defined and quantified. The technique has been applied to simultaneous Li-B trace determinations in glass samples and to Mg determination in Al₂O₃ ceramic material.     

3-Hydroxy-2-(2"-Thienyl)-4H-Chromon-4-one as a Spectrophotometric Reagent for the Trace Determination of Zirconium in an Aqueous Phase

A rapid, simple, selective, and sensitive method for the trace determination of zirconium has been developed based on the reaction of 3-hydroxy-2-(2"-thienyl)-4H-chromon-4-one in an hydrochloric acid medium to form a yellow–colored complex which is rendered water soluble by the micellar action of Triton X-100 and measured at 415 nm. Most of the metal ions do not interfere with the determination. Beer's law is obeyed in the concentration range 0–2.0 g/mL and the molar absorptivity of the complex is 2.73 × 10⁴L mol^–1cm^–1; Sandell's sensitivity is found to be 0.0034 g cm^–2. The method has been applied for the determination of zirconium in various samples, and satisfactory results have been obtained.     

Triazene-N-oxides as new type of fluorimetric reagents

Summary The fact that niobium gives orange fluorescence ( _ex ^max 570, _em ^max 540 nm) in both acid and alkali media with 3-(2-hydroxyphenyl)-1-phenyltriazene-N-oxide, has been exploited to develop a simple, sensitive and selective method for the determination of trace amounts of the metal in 50% ethanolic medium. Measurements are made at the pH range of 3.2–5.0. Fluorescence intensity attains the maximum value after 45 min of standing and remains almost unchanged after 24 h. Calibration graph maintains linearity from 50 ppb to 2.2 ppm of the metal. Forty cations and anions are without any effect on the fluorimetric determination of niobium(V). The method has been applied to the analysis of synthetic mixtures.     

Modified spectrophotometric method for the determination of traces of boron using quinalizarin in a sulfuric-acetic acid medium

Summary A modified spectrophotometric method for the determination of boron with quinalizarin in a sulfuric-acetic acid medium is proposed. The sensitivity of the method is 0.00037g/cm². The optimum concentration range is 0.06 to 0.25 ppm of boron.

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Zusammenfassung Eine modifizierte spektrophotometrische Bestimmungsmethode für Bor mit Chinalizarin in schwefelsaurer-essigsaurer Lösung wurde vorgeschlagen. Deren Empfindlichkeit beträgt 0,00037g/cm². Das optimale Konzentrationsbereich liegt zwischen 0,01 und 0,25 ppm Bor.

     

Three-dimensional analysis of trace elements with the CAMECA IMS 4F

Summary The CAMECA IMS 4F operates in the microprobe and microscope modes with submicron lateral resolutions. The high useful yields obtained via the appropriate primary ion beam species and high transmission ion optical system give access to trace analysis in small structures. As an example, a depth profile of arsenic in silicon performed at 5,000 mass resolution in a 8 m² area allows detection of 1.10¹⁶ at/cm³ (0.2 ppm).

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Dreidimensionale Analyse von Spurenelementen mit dem CAMECA IMS 4F

     

Shock tube measurements of the reactions of CN with O and O2

The rate coefficients of the reactions and were determined in a series of shock tube experiments from CN time histories recorded using a narrow-linewidth cw laser absorption technique. The ring dye laser source generated 388.44 nm radiation corresponding to the CN B²Σ⁺(v = 0) ← X²Σ⁺(v = 0) P-branch bandhead, enabling 0.1 ppm detection sensitivity. Reaction (1) was measured in shock-heated gas mixtures of typically 200 ppm N₂O and 10 ppm C₂N₂ in argon in the temperature range 3000 to 4500 K and at pressures between 0.45 and 0.90 atm. k₁ was determined using pseudo-first order kinetics and was found to be 7.7 × 10¹³ (±20%) [cm³ mol^?1 s^?1]. This value is significantly higher than reported by earlier workers. Reaction (2) was measured in two regimes. In the first, nominal gas mixtures of 500 ppm O₂ and 10 ppm C₂N₂ in argon were shock heated in the temperature range 2700 K to 3800 K and at pressures between 0.62 and 1.05 atm. k₂ was determined by fitting the measured CN profiles with a detailed mechanism. In the second regime, gas mixtures of 500 ppm O₂ and 1000 ppm C₂N₂ in argon were shock heated in the temperature range 1550 to 1950 K and at pressures between 1.19 and 1.57 atm. Using pulsed radiation from an ArF excimer laser at 193 nm, a fraction of the C₂N₂ was photolyzed to produce CN. Pseudo-first order kinetics were used to determine k₂. Combining the results from both regimes, k₂ was found to be 1.0 × 10¹³ (±20%) [cm³ mol^?1 s^?1].     

3-Hydroxy-2-(2-thienyl)-4H-chromen-4-one as a new reagent for the extraction and trace determination of molybdenum(VI)

A simple, sensitive and selective method for the extraction and trace determination of molybdenum(VI) has been developed; it is based on its reaction with 3-hydroxy-2-(2-thienyl)-4H-chromen-4-one (HTC) in sulphuric acid medium. The 1:2 Mo (VI)-HTC yellow complex is quantitatively extractable into chloroform (_max 420 nm) and is stable for more than 4 h. The procedure eliminates the interference of a large number of metal ions and complexing agents. Beer's law is obeyed in the range of 0–2.85 g Mo/mL with a molar absorptivity, Sandell's sensitivity and standard deviation of 5.28×10⁴ L mol^–1 cm^–1, 0.0018 g Mo/cm² and ±0.0054, respectively. The method has successfully been used for the spectrophotometric determination of molybdenum in steel samples.     

Determination of trace amounts of chlorine in hydraulic fluid by Instrumental Neutron Activation Analysis

A procedure has been developed for the determination by thermal neutron activation analysis of trace amounts of total chlorine in the Electro-Hydraulic-Control /EHC/ fluid used by the Hadera Power Station in various hydraulic systems. Irradiation for 1 min near the core of a nuclear reactor is followed by high resolution gamma-ray spectrometry using a Ge/Li/ detector. Chlorine amount is quantitatively determined by measuring the gamma-ray photopeaks of the radioactive nuclide³⁸Cl. The system response is linear in the concentration ranges investigated. Chlorine concentration in a fresh hydraulic fluid sample was found to be 17.6±0.5 ppm. The limit of detection, when assaying a 1 cm³ sample of fluid under the present experimental conditions, is 1 g of chlorine and the corresponding concentration is 1 ppm.     

Rapid determination of fluorine in coral skeletons by non-destructive neutron activation analysis using 20F

A rapid non-destructive technique has been proposed for the determination of fluorine in coral skeletons by thermal neutron activation analysis, using the short half-life ²⁰F nuclide (11.0 s). About 0.2-0.5 g samples were irradiated for 10 seconds in a Triga Mark II Reactor. Soon after the irradiation (25-35 s), measurements of -rays were performed with each sample and standard. The method has the drawback of low sensitivity (20 ppm of F), and the manual operation employed in the cooling step could lead to less precise measurements. We determined fluorine in coral standards within ~8% of analytical precision. The result obtained for the dolomite standard was fairly consistent with literature values, but those for the limestone standard showed to be considerably higher than the reported values. The present method was applied for the determination of fluorine in modern corals from Khang Khao Island, Thailand and Okinawa, Japan. Two core samples of an ancient reef from Funafuti Atoll were measured for fluorine to compare with modern samples. In order to understand the environmental media in which coral grew, the partition of fluorine between seawater and coral skeletons is also discussed.     

Spectrophotometric determination of thorium(IV) using 3-nitroso-4-hydroxycoumarin

Summary 3-Nitroso-4-hydroxycoumarin is suggested as a new reagent for the spectrophotometric determination of 125 g to 0.50 mg Th(IV) in 3: 1 dioxan: water medium as 1: 1 complex having orange red colour with absorption maximum at 419 nm, at pH 4.5–6.0. For the estimation of9.6 ppm Th(IV) 100-folds acetate, citrate, tartrate; 50 ppm UO₂ ²⁺, 75 ppm Ce³⁺, La³⁺, Gd³⁺; 4.5 ppm Ce⁴⁺; 25 ppm Tm³⁺, Zr⁴⁺; and 100 ppm Ti⁴⁺, V⁵⁺, MoO₄ ^2– and WO₄ ^2– do not interfere.

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Zusammenfassung 3-Nitroso-4-hydroxycoumarin wird als neues Reagens für die spektrophotometrische Bestimmung von 125 g bis 0,50 mg Th(IV) in Dioxan: Wasser = 3: 1 als 1: 1-Komplex mit orange-roter Farbe mit einem Absorptionsmaximum bei 419 nm bei pH 4,5–6,0 empfohlen. Bei einem Einsatz von 9,6 ppm Th(IV) stört die hundertfache Menge Acetat, Citrat, Tartrat nicht. Auch 50 ppm UO₂ ²⁺, 75 ppm Ce³⁺, La³⁺, Gd³⁺, 4,5 ppm Ce⁴⁺, 25 ppm Tm³⁺, Zr⁴⁺, 100 ppm Ti⁴⁺, V⁵⁺, MoO₄ ^2– bzw. WO₄ ^2– stören nicht.

     

Spectrophotometric and polarographic studies of pyridin-2-aldehyde guanylhydrazone-Fe(II) system

The analytical properties of iron(II)-PAG system are described. The optimal conditions for a spectrophotometric determination of iron are

shown. A determination of Fe(II) with PAG can be performed in a concentration range varying from 0.5 to 4.7 ppm of iron, the molar absorptivity is 1.3 × 10⁴ liters · mol^?1, at 380 nm and the relative error (95% confidence level) is ±0.3% for 1.9 ppm of iron.A polarographic behavior of iron(II)-PAG system has been attempted. Iron gives well-defined diffusion-controlled reduction wave with half-wave potential ?0.42 V at 8.5 pH value. The electrode process is discussed.     

Direct determination of trace amounts of arsenic in powdered biological samples by atomic absorption spectrometry using an inner miniature cup for solid sampling techniques

Summary A new easy solid sampling technique with atomic absorption spectrometry by using an inner miniature cup in conjunction with the cupped type furnace was proposed for the direct determination of arsenic in NBS, NIES standard materials and marine organisms. A mixture of 3 M sulfuric and 4 M nitric acid solution containing 60 g of nickel was successfully used as the matrix modifier for the powdered samples examined. Optimum experimental conditions were determined based upon detailed examinations for the trace amount determination of arsenic in these samples. Analytical sensitivity and accuracy of this method were compared to the arsine generation followed by atomic absorption or ICP emission spectrometry. The standard deviations for 7–15 ppm As were found to be 3–10%.

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Direkte Bestimmung von Arsenspuren in pulverföraügen biologischen Proben durch AAS mit Hilfe eines im Ofen einsetzbaren Miniaturbechers für feste Proben

Zusammenfassung Zur direkten Arsenbestimmung in NBS und NIES-Referenzmaterialien sowie Meeresorganismen durch AAS wurde ein in einen entsprechenden Ofen einsetzbarer Minaturbecher verwendet. Als Matrixmodifikator wurde ein Gemisch von 3 M Schwefel- und 4 M Salpetersäure mit 60 g Ni benutzt. Die optimalen Bedingungen wurden durch detaillierte Untersuchungen gefunden. Empfindlichkeit und Genauigkeit des Verfahrens wurden mit der Methode der Arsinerzeugung mit nachfolgender AAS oder ICP-AES verglichen. Relative Standardabweichungen von 3–10% für 7–15 ppm As wurden gefunden.

     

Determination of traces of antimony, copper, and lead in titanium dioxide by pulse polarography

Summary Traces of antimony, copper, and lead impurities in titanium dioxide have been determined simultaneously by pulse polarography. The three metals were separated from titanium(IV) by sulphide precipitation at pH 3, using cadmium as carrier and complexing titanium with fluoride. The precipitation of lead was supplementary controlled with the radio-isotope ²¹⁰Pb, showing a quantitative recovery. In hydrochlorid-hypophosphite supporting electrolyte, antimony, copper, and lead in titanium dioxide can be determined as low as 0.15, 0.03, and 0.1 ppm respectively. The method was applied in the analysis of various titanium dioxide products commercially available, showing satisfactory sensitivity and resolution for divergent copper-antimony ratios.

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Zusammenfassung Zur gleichzeitigen Bestimmung von Spuren Antimon, Kupfer und Blei in Titandioxid wird ein impulspolarographisches Verfahren beschrieben. Die drei Elemente werden durch Sulfidfällung bei pH 3 von Ti^IV abgetrennt, wobei Cadmium als Träger dient und Titan mit Fluorid maskiert wird. Die Fällung des Bleis wurde mit Hilfe des Radioisotops ²¹⁰Pb geprüft und die eingesetzten Mengen quantitativ wiedergefunden. In einem Leitelektrolyten aus HCl-NaH₂PO₂ können noch 0,15 ppm Sb, 0,03 ppm Cu und 0,1 ppm Blei in Titandioxid bestimmt werden. Das Verfahren wurde für verschiedene handelsübliche Titandioxidsorten verwendet, wobei befriedigende Ergebnisse, auch für sehr unterschiedliche Cu-Sb-Verhältnisse, erhalten wurden.

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Dedicated to Prof. Dr. M. von Stackelberg on his 70th birthday.     

Pyridine ketoximes as analytical reagents. XVII

Summary The application of 2-pyridyl-2-thienyl--ketoxime to the spectrophotometric determination of trace amounts of palladium(II) is described. The effects due to pH, time, reagent concentration, temperature and diverse ions are reported. Beer's law is obeyed in the range of 0.15 to 2.10 ppm and the molar extinction coefficient at 433 nm is 9.18×10³.

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Zusammenfassung Die Anwendung von 2-Pyridyl-2-thienyl--ketoxim für die spektrophotometrische Bestimmung von Palladium(II)-Spuren wurde beschrieben. Über den Einfluß des pH, der Zeit, der Reagens-Konzentration, der Temperatur und verschiedener Fremdionen wurde berichtet. Das Beersche Gesetz ist zwischen 0,15 und 2,10 ppm erfüllt. Der molare Extinktionskoeffizient bei 433 nm beträgt 9,18×10³.

     

Determination of the fluoride distribution in rabbit bone using instrumental neutron activation analysis

An instrumental neutron activation analysis (INAA) technique, based on the¹⁹F(n,)²⁰F reaction, has been development for the determination of fluoride in bone. The purpose was to study fluoride distribution in different kinds of bone samples using a rabbit model. The rationale for the study stems from the posible correlation between fluoride in bone and osteoporosis. The sodium concentration in the bone was used to correct the²⁰F peak area for the²³F(n,)²⁰F contribution. Two secondary standards, teflon tape and teflon coated dacron line, were used to quantify fluoride concentration. They proved to be stable and consistent with respect to their fluoride concentration. Bone specimens from 10 sites and two tooth samples were analyzed for fluoride. Fluoride concentration ranged from 305 ppm in the tibia long bone to 585 ppm in the humerus trochanter end and the magnitude of fluoride concentration levels is age depdentent. The detection limit of the fluoride is approximately 5 ppm using a 100 mg bone sample.     

Multiphoton ionization of methyl radicals in CH4 pyrolysis

The technique of resonance enhanced multiphoton ionization has been applied to in situ detection of methyl radicals in high-temperature atmospheric pressure CH₄ pyrolysis. The detection is via three-photon ionization using two-photon resonances to the 3p ²A″₂ state of CH₃ at 333.5 and 329.5 nm for the 0⁰₀ and 2¹₁ bands, respectively. Deuterium isotope shifts in both bands are also observed in CD₄ pyrolysis. The detection sensitivity is estimated to be at the ppm level. The methyl radical concentration profiles are measured as a function of reaction time.