Prochlorperazine bismethanesulfonate: Sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium

Prochlorperazine bismethanesulfonate (PCPMS) is proposed as a new sensitive and selective reagent for the spectrophotometric determination of microgram amounts of osmium. PCPMS forms a red-colored species with osmium(VIII) or osmium(VI) instantaneously at room temperature in 5 M phosphoric acid medium. The red species exhibits maximum absorbance at 529 nm. Beer's law is valid over the concentration range 0.05–3.6 ppm for osmium(VIII) and 0.15–6.4 ppm for osmium(VI). Sandell's sensitivity of the reaction is 2.89 nm cm^?2 for osmium(VIII) and 4.24 ng cm^?2 for osmium(VI). The effects of time, temperature, acidity, order of addition of reagents, reagent concentration, and diverse ions are investigated. The application of the proposed method in the determination of osmium content in synthetic ores has been explored.     

Sorption-colorimetric and test determination of osmium in alloys and concentrates

A test is proposed for the evaluation of the concentration of osmium in solutions based on the direct proportionality between the concentrations of osmium(IV) or osmium(VI) and the length of the colored zone on the indicator paper; the latter is covered by a polymer film and is in contact with the test solution along one edge. The paper is impregnated by 3-methyl-2,6-dimercapto-1,4-thiopyrone, which reacts with osmium ions in the solid phase and forms poorly soluble products. The effectiveness of the dynamic preconcentration of osmium(IV) from solutions, obtained upon the reduction of its volatile tetroxide for the subsequent visual test and colorimetric determination on paper filters in the total concentration range 4–400 μg in samples for a sample volume of 100 mL, is demonstrated. The procedures developed are utilized for the determination of osmium in ore processing wastes from Dzhezkazgan’s mines and in its alloys.     

Microdetermination of osmium by oxygen-flask combustion of the sample

A relatively simple and convenient procedure for the determination of osmium in its compounds has been worked out. It is based on the oxygen-flask combustion of the sample followed by the spectrophotometric determination of osmium with 4-(2-pyridylazo)-resorcinol. Possible modifications of the final method are suggested in order to overcome interferences caused by sulfur.     

Spectrophotometric determination of osmium: Sulphanilic acid as a reagent

Sulphanilic acid has been found to be a very effective reagent for the spectrophotometric determination (if hexavalent and octavalent osmium in the pH range between 1.8 – 3.5. In these two valence states, the element forms a dark-violet complex with the reagent, the absorption maximum of the complex being at 490 mμ. As most of the other ions interfere in the determination, the element must be separated as osmic acid by nitric acid distillation. Beer's law is obeyed in the case of 0.5 to 9 p.p.m. of osmium (VIII) and l to 18 p.p.m. of osmium (VI); tin-optimum concentration ranges are from 2 to 8 p.p.m. for osmium(VIII) and from 4 to 16 p.p.m. for osmium(Vl). In these ranges, the % relative errors per 1% absolute photometric error are 3.02 for osmium (VIII) and 3.1 for osmium(VI). Application of the method of continuous variations and the molar ratio method indicates that in solution hexavalent osmium and the reagent form a 1:2. complex, with an average dissociation constant of 1.2 ? 10^-7.     

New reagent for indirect spectrophotometric red-ox determination of osmium (Ⅵ)

A highly sensitive indirect spectrophotometric red-ox method for the determination of osmium is reported. The method is based on the oxidation of iodide by osmium (VI) and the spectrophotometric detection of the liberated iodine in the form of complex anion and ion associate with 2-(4-diethylaminostyryl)-1,3,3-trimethyl-6-nitro-3H-indolium chloride reagent. The appropriate reaction conditions have been established. The molar absorptivity is (1.6-5.6)×104 L mol-1cm-1. Beer's law holds for the concentration range of 0.5-11.4μgmL-1 of Os(Ⅵ).     

Determination of aqueous plutonium oxidation states by solvent extraction

The reliability of two solvent extraction techniques for the determination of Pu oxidation states in solution was tested with low-ionic-strength solutions and with high-Na and high-Mg brines that contained Pu concentrations sufficient for spectrophotometric analysis. One procedure only differentiates between reduced Pu [Pu(III) and Pu(IV)] and oxidized Pu [Pu(V) and Pu(VI)], whereas the second procedure was designed to differentiate between Pu(IV), Pu(V), and Pu(VI) in solution. Both procedures successfully differentiated between oxidized and reduced Pu in both dilute solutions and brines when tested with samples that contained only the Pu(IV), Pu(V), or Pu(VI) oxidation states. However, when the second solvent extraction procedure, which differentiates between Pu(V) and Pu(VI), was employed for solutions that did not contain a strong oxidant to maintain the Pu(VI) oxidation state, significant quantities of Pu(VI) were reduced to Pu(V) during extraction, indicating that accurate quantification of Pu(V) and Pu(VI) is not possible with this procedure.Work supported by the U. S. Department of Energy under Contract DE-ACO6-76RLO 1830.     

Enhanced spectrophotometric determination of chromium (VI) with diphenylcarbazide using internal standard and derivative spectrophotometry

In the present work, erioglaucine A was applied as internal standard to enhanced spectrophotometric determination of chromium (VI) with diphenylcarbazide. The following procedure was used: (1) addition of internal standard and formation of ion pairs of Cr (VI) with benzyltributylammonium bromide (BTAB) (sample volume 100 ml), (2) extraction to 10 ml of methylene chloride, (3) evaporation in nitrogen stream, and (4) redissolution in a micro-volume with addition of diphenylcarbazide for color development (final volume 200 mul). The preconcentration factor achieved was about 400 and it was shown that, using internal standard, the analytical errors due to sample treatment were reduced. The analytical signals for chromium and internal standard were obtained at 591.30 and 653.50 nm from first derivative spectra, normalized against (1)D(653.50nm). The analytical characteristics evaluated were: detection limit = 0.06 mug l(-1), quantification limit = 0.19 mug l(-1), precision for 1 mug l(-1) 14.2%, and for 10 mug l(-1) 3.2%, correlation coefficient of linear regression was 0.9985. The proposed procedure was applied to determination of chromium (VI) in tap water. Total chromium was determined by electrothermal atomic absorption spectrometry, the recovery of hexavalent chromium added was then evaluated and compared with the results of the proposed procedure. In this experiment, good agreement was obtained between results obtained by the two methods.     

Determination of osmium by the sorption-X-ray fluorescence technique

Sorption of osmium(IV, VI) on complexing sorbents POLYORGS XXIV, POLYORGS 32 M, and POLYORGS 32 V and on the PVA-PGMA-PEPA sorbent from alkaline and hydrochloric acid solutions is studied. It is demonstrated that equilibrium in systems under study is attained within 40 min for the POLYORGS XXIV sorbent and within 2.5 h for the POLYORGS 32 V sorbent and that the sorbents exhibit a sufficiently high sorptive capacity with respect to osmium: from 3.4 to 8 mg of Os(VI) in alkaline solutions and 2.2 mg of Os(IV) in acidic solutions. Optimal conditions of analysis of a concentrate on an EDX-771 energy-dispersive X-ray fluorescence spectrometer are revealed and, on this basis, a sorption-X-ray fluorescence method that provides the determination of osmium in a wide concentration range with the detection limit down to 10^-6% is developed.     

New reagent for indirect spectrophotometric red-ox determination of osmium （Ⅵ）

A highly sensitive indirect spectrophotometric red-ox method for the determination of osmium is reported. The method is based on the oxidation of iodide by osmium （Ⅵ） and the spectrophotometric detection of the liberated iodine in the form of complex anion and ion associate with 2-（4-diethylaminostyryl）-1,3,3-trimethyl-6-nitro-3H-indolium chloride reagent. The appropriate reaction conditions have been established. The molar absorptivity is （ 1.6-5.6） × 10^4 L mol^-1 cm^-1. Beer＇s law holds for the concentration range of 0.5-11.4 μg mL^-1 of Os（Ⅵ）.     

2-Amino-3-hydroxypyridine as a chromogenic reagent for the spectrophotometric determination of osmium

2-Amino-3-hydroxypyridine forms two coloured complexes, green and violet, with osmium, depending on the pH of the solutions. Based on this reaction, a selective and sensitive spectrophotometric method for the determination of osmium (3-13 ppm in the final solution) alone and in the presence of other metal ions has been developed.     

Features of the Sorptive Extraction of Osmium in Different Oxidation States with Silica Gels Chemically Modified with Mercapto and Disulfide Groups

The sorptive extraction of osmium(VIII, VI, IV) from HCl solutions with silica gels chemically modified with mercapto groups (MPS) and disulfide groups (DPDSS) was studied. The recovery of osmium(VIII) from 0.5–4 M HCl is 99 and 25% with the sorption equilibration time 5 and 20 min for MPS and DPDSS, respectively. The equilibration time for the extraction of Os(VI) with MPS is no longer than 1 min. The recovery from 0.1–4 M HCl is up to 99.9%. The recovery of osmium(VI) with DPDSS decreases from 96 and 80% when going from 0.5 M to 4 M HCl. The quantitative extraction of osmium(IV) is attained at 95°C in the presence of tin(II) chloride and the equilibration time 60 min. Without tin(II) chloride, osmium(IV) is not extracted with these sorbents. The difference in the sorption ability of chemically modified silica gels with respect to osmium in different oxidation states can be used for the extraction of osmium(VI) and osmium(IV) and their separate determination directly in the MPS phase with the use of diffuse reflectance spectrometry.     

Spectrophotometric determination of osmium with 1-naphthylamine-4,6,8-trisulfonic acid

This investigation was undertaken to determine if the naphthylamine sulfonic acid-osmate (OsVI) reaction is suitable for a spectrophotometric determination of osmium. The 1-naphthylamine- 4, 6,8-trisulfonic acid osmate complex is water-soluble and forms a stable violet-colored system at PH 1 to 1.5 that is independent of reagent concentration. At 555 mμ the colored complex obeys Beer's law over a concentration range of 0.1 to 6.5 p.p.m. osmium and remains stable with respect to time and temperature. The effects of pH, temperature, reagent concentration, and diverse ions were studied. The nature of the organo-osmate complex in solution was studied by three techniques and the effect of temperature and pH on the rate of complex formation was determined. A procedure for the removal of osmium from all interfering ions was developed based on well known distillation techniques.A convenient, sensitive, reproducible and accurate method for the spectrophotometric determination of osmium has been developed.     

Spectrophotometric determination of ruthenium and osmium

The optimum conditions for preparation of stable solutions of ruthenate and osmate, after alkaline fusion of ruthenium(IV) compounds, ruthenium metal and osmium metal in a silver crucible, have been determined. The molar absorptivities of ruthenate and osmate are 1.74 × 10³ 1. mole⁻¹.cm⁻¹ at 465 nm (Ru) and 2.75 × 10³ 1.mole⁻¹.cm⁻¹ at 340 nm (Os) in 2M sodium hydroxide. A differential spectrophotometric method has been developed for determination of ruthenium in ruthenium dioxide, lead ruthenite and bismuth pyroruthenate. Simultaneous spectrophotometric determination is proposed for ruthenium and osmium. The other platinum metals interfere seriously only when present in> 1:1 w/w ratio to Ru.     

停流流动注射-诱导动力学光度法同时测定微量铁和锑

依据诱导反应的基本原理, 提出了一种同时测定多元素的方法; 研究了Fe(II)、Sb(III)诱导的Cr(VI)-I^-氧化还原反应体系, 并据此建立了停流-诱导动力学光度法同时测定微量铁和锑的工作条件。线性范围分别为0~1.2μg.mL^-1Fe(II)和0~2.0μg.mL^-1Sb(III); 检测限为0.012μg/mL^-1Fe(II)和0.014μg.mL^-1Sb(III)。除Ti(III)、V(IV)及As(III)外, 其余共存离子不影响测定。用本法测定了锌标准物及模拟样品中的铁和锑含量, 结果满意。     

Triphenyltetrazolium chloride as a new analytical reagent for molybdenum(VI): Application to plant analysis

Solvent extraction of molybdenum(VI) ion associate with triphenyltetrazolium chloride (TTC) has been studied. TTC was proposed as reagent for the spectrophotometric determination of micro amounts of molybdenum(VI) at λ_max 250 nm. The optimum conditions for extraction of molybdenum(VI) as an ionassociation complex with TTC has been determined. Beer’s law is obeyed in the range of 0.5–10 μg/mL molybdenum(VI). The molar absorptivity of the ion-pair is 1 × 10⁶ L/mol cm. The sensitivity of the method is 9.6 × 10⁻⁵ μg/cm². The characteristic values for the extraction equilibrium and the equilibrium in the aqueous phase are: distribution constant K _D = 32.64, extraction constant K _ex = 2.19 × 10¹⁰ association constant β = 6.71 × 10⁸. The interferences of different cations, anions on molybdenum(VI) determination were also investigated. A sensitive and selective method for the determination of microquantities of molybdenum(VI) has been developed. The determination was carried out without preliminary separation of molybdenum. A novel procedure of molybdenum(VI) extraction and spectrophotometric determination in different plant samples was examined.     

A novel reagent for spectroscopic determination of Mo(VI)

A new reagent for spectrophotometric determination of Mo(VI) was developed utilizing micellar effects. For this purpose, differences in the ultraviolet and visible spectral properties of Mo(VI), gallic acid, L-serine, and their binary and ternary solutions were studied in the presence and absence of cationic, anionic, and non-ionic surface active agents. L-serine was observed to form binary complexes and a ternary complex with Mo(VI) and gallic acid below its isoelectric point. The maximum Mo(VI) sensitivity was exerted by the Mo(VI) + gallic acid + L-serine + hexadecyltrimethylammonium bromide system at pH of 4.5. This system was proposed for use in the spectrophotometric determination of Mo(VI) as a superior alternative to the Mo(VI) + gallic acid + hexadecyltrimethylammonium bromide system and to most of the instrumental analysis methods referred to in the literature. The mechanism of micellar effects was discussed on the basis of the spectral data obtained above and below the isoelectric point of L-serine and explained in terms of the molecular charge of the substrates and the surfactants.     

The Simultaneous Spectrophotometric Determination of Osmium and Ruthenium

Abstract

A spectrophotometric procedure is described for the simultaneous determination of osmium and ruthenium in the form of bromo complexes. It was found that a blue ruthenium-thiourea complex could be formed in 6.7 M HBr solutions while the osmium could be maintained as the hexabromoosmate complex. Absorption maxima were at 620 μ for the ruthenium complex and at 446 μ for the osmium complex. Molar absorptivities for the ruthenium complex were 2.47 × 10³ at 620 μ and 763 at 446 μ. For the osmium complex molar absorptivities were 328 at 620 μ and 6.81 × 10³ at 446 μ. The method is useable over the range of 5 to 30 ppm with an absolute error of = 1 ppm over the range. Other platinum metals interfere.     

塑料中痕量Cr(VI)的RoHS符合性测定及影响因素分析

六价铬Cr(VI)的不稳定性使其成为RoHS(限定有害物质, Restriction of Hazardous Substances)符合性测试的难点之一. 采用分光光度法对塑料中痕量Cr(VI)进行检测, 着重研究Cr(VI)萃取与显色中的过程参数与干扰因素的影响, 并建立了一套试样制备、萃取、显色等标准程序. 研究表明, 采用混合碱萃取法可对Cr(VI)进行有效提取, 同时消除Cr(III)的干扰, 通过排除共存离子影响, 优化萃取、显色、标定过程中pH值、温度和时间等参数, 可使试样和加标溶液的回复率保持在90%～110%之间, RSD＜1%, 校准在低浓度范围(0～500 μg/L)呈良好线性关系. 提出的方法和检测程序具有较高的精确度和灵敏度, 而且操作简单、快速, 为信息产业应对RoHS符合性测试提供了较好的技术支持.     

Differential estimation of U(VI) and U(IV) ions in aqueous solutions by Arsenazo 1

The spectrophotometric determination of pure U(IV) or U(VI) ions in solution with Arsenazo I is greatly dependant on the pH of the solutions. The experimental conditions for the differential estimation of the different oxidation states of U ions, in the same sample, using Arsenazo I have been identified and implemented. The results showed that the applied method is rather rapid and accurate.     

Derivative spectrophotometry in the determination of phenyl-beta-naphthylamine used as an antioxidant in rubber mixtures

A method for the determination of phenyl-beta-naphthylamine (PBN) in ternary mixtures by second-derivative spectrophotometry is described. The procedure works without any separation step of PBN from the other polymer additives. By applying the second-derivative spectrophotometry, Beer's law was valid over the range 0.25-10 micro g mL(-1). The proposed method has been applied to the determination PBN in synthetic ternary mixtures and rubber samples. A comparative study of the results obtained using the second and the third-derivative spectrophotometric methods is presented and evaluated. The derivative spectrophotometric method indicated that the amount of PBN found after extraction from the rubber samples was 0.97+/-0.02 g/100 g of sample.