Determination of Gallium By Liquid-Liquid Extraction-Flame Atomic Absorption Spectrometry In Bayer Process Aluminate Solutions

Abstract

The described flame-atomic absorption determination of gallium involves the extraction of 8-hydroxyauinoline-Ga complex and the extraction of galhum as an ion association complex from strong hydrochloric acid into Methyl Isobutyl Ketone (MIBK). Both of the examined extraction systems were found to be workable for gallium determination in aqueous solutions. A comparison of mentioned extraction systems showed that only the second one can be applied for gallium determination in low concentration in aluminate solutions (strong alkaline). Finally, an analytical scheme for gallium determination in aluminate solutions is recommended (extraction of Ga from hydrochloric acid solutions, 3.0-50M, through matrix matched calibration curve). the proposed procedure was found to be simple, selective and accurate.     

Determination of Hg Traces in Gallium By Anodic Stripping Voltammetry on Glassy Carbon

Abstract

An A.S.V. method for determination of mercury in ultrapure gallium has been developed. The procedure is very simple and allows a sensitivity high enough to verify the highest purity level of Ga as concerns Hg traces (i.e. 1×10^?5 % Hg in Ga by weight).

The above method was applied to some samples of gallium used in this laboratory.     

Control of the composition of lanthanum gallium silicate by laser ablation inductively coupled plasma mass spectrometry

The possibilities of determining the impurities and basic components of lanthanum gallium silicate using laser ablation in combination with inductively coupled plasma mass spectrometry (LA-ICP-MS) were shown. A procedure for the determination of 54 impurity elements with the limits of determination from n × 10^?5 wt % for Mg, Ti, V, Cr, Mn, Ni, Cu, and Zn to 2 × 10^?7 wt % for U and also a procedure for the determination of a ratio between basic components were developed. It was found that the concentration ratios between gallium and lanthanum and silicon and lanthanum in the crystals of lanthanum gallium silicate remained constant upon consecutive melting operations with the addition of a charge mixture to the crucible.     

Pyrocatechol-1-Aldehyde 2-Benzothiazolylhydrazone As Reagent for the Spectrofluorimetric Determination of Nanogram Amounts of Gallium in Urine and Blood Serum

Abstract

A method is developed for the spectrofluorimetric determination of 1–80 ng.ml^?1 of gallium with pyrocatechol-1-aldehyde 2-benzothiazolylhydrazone, in a 50% (v/v) DMSO-Water medium at apparent pH 4.0 (monochloracetic/monochloracetate buffer). Λ_ex = 400nm, Λ_em = 504 nm (corrected). Interferences have been evaluated and the method applied to the determination of gallium in human urine and blood serum samples.     

The Determination of Trace Amounts of Tellurium and Selenium in Gallium Metal

Abstract

Analytical methods have been developed for the separation, concentration and determination of trace quantities of tellurium and selenium from primary and scrap gallium metal. A chloroform extraction is made of the tellurium diethyldithiocarbamate complex at a pH of 8.5. This extraction, in the presence of ammonium citrate, allows the satisfactory determination of tellurium by emission or atomic absorption spectrohcopy. The limit of sensitivity of the method is 0.5 pg of tellurium in 1.0 gram of gallium (0.5 ppm Te).     

Determination of gallium in biological fluids using inductively coupled plasma mass spectrometry

A procedure for the determination of gallium in biological fluids by inductively coupled plasma mass spectrometry was developed. The detection limits of gallium calculated from the 3s value were 60 ng/L for urine, 32 ng/L for a model solution of intestinal juice, and 50 ng/L for serum. The accuracy of the procedure was tested using a standard addition method. The nature of a background signal on the masses of gallium isotopes was studied with the use of a high-resolution mass spectrometer, and the background concentration of gallium in biological fluids was evaluated (5–7 ng/L). It was found that a background level in measurements performed on a quadrupole mass spectrometer depends on the interfering influence of polyatomic ions with close m/z ratios rather than on the background concentration of gallium. The procedure makes it possible to study the stability of pharmaceutical preparations based on gallium in biological media, their metabolism, and the excretion of preparations from the body.     

Facile and Efficient Deoxygenation of Amine‐N‐oxides with Gallium in Water

Abstract

A facile and efficient procedure for the deoxygenation of amine‐N‐oxides with gallium metal in water is described. The experimental procedure is quite simple and the products are obtained in high yields without any activating agent.     

Spectrofluorimetric Determination of Gallium with 5-Bromosalicylidene-o-Aminophenol

Abstract

A method for the determination of trace amounts of gallium has been developed, based on the formation of a fluorescent complex between Ga (III) and 5-Bromosalicylidene-o-aminophenol (5-BrSOAPh). With excitation at 425 nm the chelate has an emission maximum at 520 nm. The reaction is carried out at apparent pH (pH?) 5.40 in an aqueous-ethanol medium (60% V/V ethanol). The influence of the reaction variables is discussed.     

The Spectrophotometric Determination of gallium (III) Using O-Hydroxyhydroquinonephathalein in the Presence of Surfactant Micellar

Abstract

The color reaction systems between various metal ions and o-hydroxyhydroquinonephthalein(Qnph) as a xanthene dye, in the presence of various water soluble surfactants(cationic. anionic, non-ionic surfactants) alone or in combination, were systematically investigated at various pH areas. The coexistence of cationic and non-ionic surfactants, such as Zephiramine (Zp) and Brij 35, was most effective for the color reaction systems between Qnph and gallium(III), as a metal ion, at weakly acidic media. By using the color reaction between Qnph and gallium(III) in the coexistence of Zp and Brij 35, an improved and sensitive spectrophotometric determination of gallium(III) was proposed as method 1, and the calibration curve was rectilinear in the range of 0～7.0 μg of gallium(III) in a final solution of 10ml at pH 6.4. The apparent molar absorptivity was 1.5 × 10⁵ 1 mol^?1 cm^?1 at 560 nm, and the interference of foreign ions was decreased by ½～ ¼-fold in comparison with other methods; method 3—in the presence of Zp alone at pH 6.4, method 2—in the presence of Tween or Brij 35 alone, without Zp, at pH 8. Thus, the use of Qnph as a xanthene dye and the combination of cationic and non-ionic surfactants, such as Zp and Brij 35(perhaps, on the mixed micellar media), was most effective and its color reaction was used for the separative assay of gallium(III).     

Application of galvanic stripping analysis to trace determination of tin

A simple, rapid and reliable procedure for the determination of tin by galvanic stripping analysis is described. The determination includes (i) preconcentration of tin onto preformed mercury film glassy carbon electrode, and (ii) re-oxidation in open-circuit position by advantageously utilizing the localized galvanic couple formation (in the absence of external electrical field or oxidant in solution). The details of the development of such a procedure and its application to the determination of tin in pure zinc materials are discussed.     

The Determination of Sodium Monofluoroacetate (Compound 1080) in Formulation and Technical Samples by High Pressure Liquid Chromatography

Abstract

A high pressure liquid chromatographic (HPLC) procedure was developed for the determination of sodium monofluoroacetate (Compound 1080). The procedure utilized an amine (NH₂) bonded column for the reverse phase determination of sodium monofluoroacetate in formulation and technical samples.     

Determination of trace elements in gallium arsenide by graphite-furnace atomic absorption spectrometry after pretreatment in gas streams

Atomic absorption spectrometry (AAS) with a resistively-heated graphite furnace is used for the determination of chromium (0.3–1 atom/10⁶ atom) in chromium-doped gallium arsenide after pretreatment in a separate furnace in a stream of argon to remove arsenic, and of manganese and silver (0.03 and 0.04 atom/10⁶ atoms, respectively) by a similar procedure after pretreatment with argon and chlorine, the latter to remove both gallium and arsenic as volatile chlorides. Results for chromium were in agreement with those obtained by furnace AAS after dissolution and by spark-source mass spectrometry (SSMS) but AAS after dissolution is more precise. Results for manganese and silver obtained by both gas pretreatments were in good agreement, but were higher than those obtained for presparked material by SSMS, indicating that surface contamination of gallium arsenide was not completely removed by the etching methods used. The procedures established that the concentrations of bismuth, indium and lead in the gallium arsenide sample were below the limits of detection of 3 × 10^?3, 10 × 10^?3 and 1 × 10^?3 atom/10⁶ atoms, respectively. In all cases, calibration graphs were constructed from data obtained with aqueous solutions of appropriate salts.     

Kinetic spectrophotometric determination of indium/gallium mixtures

A kinetic method is presented for the determination of 0.5–5 μg ml^?1 gallium based on its activating effect on the copper(II)-catalyzed oxidation of 4,4′-dihydroxybenzophenone thiosemicarbazone by hydrogen peroxide. The reaction is monitored spectrophotometrically at 415 nm. Two sets of reaction conditions are established; one for the direct determination of gallium, and another, in which indium affects the gallium response, for determination of indium. Mixtures of these cations can be determined at μg ml^?1 levels and in gallium/indium ratios from 7.5:1 to 1:1.6, with an accuracy and precision of ca. 4.5%.     

Differential Pulse Polarographic Determination of Gallium and Niobium in Samples After Preconcentration of Their Quinolin-8-Olate Complexes on Microcrystalline Naphthalene

Abstract

Gallium and niobium react with quinolin-8-ol to form water insoluble complexes which are quantitatively adsorbed on microcrystalline naphthalene from the large volume of their aqueous solutions in the pH range of 3.5 - 8.2 and 6.2 - 9.4, respectively. After filtration, the metal complexes were desorbed with 10 ml of HCl (1M for Ga and 11 M for Nb) and determined by using a differential pulse polarograph (DPP). The dissolved oxygen is removed by adding a few milliliters of 4% NaBH₄ solution in the case of gallium. The detection limits are 0.04 ppm for gallium and 0.05 ppm for niobium at the minimum instrumental settings (signal to noise ratio = 2). The linearities are maintained in the concentration range 0.1 - 5.0 ppm for gallium and 0.4 - 6.0 ppm for niobium with correlation factors of 0.9997 and 0.9996 and relative standard deviations of 0.81 and 0.95%, respectively.

Characterization of the electroactive process included an examination of the degree of reversibility. Various parameters such as the effect of pH volume of aqueous phase, reagent and naphthalene concentrations and the interference of a large number of anions and cations on the estimation of these elements were studied in detail. The method is found to be highly selective, fairly sensitive, rapid, simple and economical. It has been applied for the trace determination of gallium and niobium in various standard alloys and may be applied safely for the analyses of complex materials like environmental samples and ores.

     

Electrothermal Vaporization of Trace Gallium via In SITU Alkylation for Inductively Coupled Plasma Atomic Emission Spectrometry

Abstract

A sample introduction method based on alkylation of the analyte was proposed for introducing trace gallium into inductively coupled plasma for atomic emission spectrometry. By using 10 μl of a sample solution with 15 μl of a 0.9 mol 1^-1 solution of ethylmagnesium bromide in tetrahydrofuran as alkylating reagent, a detection limit of 1.9 ng of gallium was obtained and the calibration graph was linear with the amount of gallium up to 100 ng. The relative standard deviation (n = 10) was 2.0% when 10 ng of gallium was present in the sample.     

Photometric determination of traces of antimony with rhodamine b after sulfide precipitation

A method is described for the colorimetric determination of as little as a few tenths of a part per million of antimony in samples composed primarily of elements of atomic numbers 1–28 (e.g., geo materials).Antimony is isolated by sulfide precipitation in mineral acid medium after reduction of ferric iron with hydroxylamine hydrochloride, with final determination by rhodamine B-benzene extraction. The procedure provides for the presence of gallium, thallium, tungsten and gold.     

Determination of Trace Elements in Pharmaceutical Tablets Using Anodic stripping Voltammetry

Abstract

Anodic stripping voltammetry is applied for measurement of copper and zinc in pharamaceutical formulations. Because of the inherent sensitivity and selectivity of stripping voltammetry toward amalgam forming metals, no sample preparation is required (except for acidic dissolution). Copper-zinc intermetallic interferences are eliminated by the addition of an excess of gallium or through utilization of a dual working electrode approach. Automation of this procedure is indicated from flow injection measurments at a rate of 15 per hour.     

Adsorptive Cathodic Stripping Voltammetric Method for Determination of Gallium Using an In Situ Plated Lead Film Electrode

The in situ plated lead film electrode was proposed for the first time for adsorptive stripping voltammetric determination of gallium in water samples. The method was based on simultaneous lead film formation and Ga(III)‐cupferron complex preconcentration at ?0.7 V and its cathodic stripping during the potential scan. The composition of the supporting electrolyte, cupferron concentration, conditions of lead film formation, potential and time of accumulation were studied in detail. Under optimum conditions the limit of detection was 3.8×10^?9 mol L^?1. The proposed procedure was validated in the course of Ga(III) determination in waste water certified reference materials.     

Spectrophotometric determination of traces of gallium and indium with 1-(2-pyridylazo)-2-naphthol

1-(2-Pyridylazo)-2-naphthol (PAN) reacts with either gallium or indium at pH 5–6 giving a red complex in an aqueous medium in the presence of N.N-dimethyl-formamide. The maximum absorption of both PAN complexes of gallium and indium in an aqueous solution is at 545 mμ. The gallium-PAN complex shows a characteristic enhancement of color by addition of small amounts of ethers. Based on this selective enhancement reaction, gallium can be determined in the presence of other metals without separation. The results of determining gallium and indium in the presence of each other are reported. Both gallium and indium form M₂(PAN)₃; but in the presence of certain organic solvents, a different gallium complex, Ga(PAN)₅, and the same indium complex, In₂(PAN)₃, are formed. The reaction of PAN with cadmium can be masked by iodide; an example of determining indium in the presence of cadmium is given. The PAN method has a sensitivity of 0.003 μg/cm² for gallium and 0.005μg/cm² for indium and an absorptivity of 24,900 for the Ga-PAN complex and of 24,500 for the In-PAN complex, respectively. The methods have been successfully applied to the determination of both gallium and indium in germanium thin films.     

The Determination of Cerium on Manganese Dioxide

Abstract

This paper recommends a simple and convenient procedure for the determination of cerium(III) on MnO₂ without separation of Mn. Several reducing agents and optimum conditions of determination were studied.