阀切换-离子色谱法测定高纯硼酸中的痕量阴离子

研究了高纯硼酸中痕量阴离子的离子色谱测定方法.建立了使用阈切换技术联合离子色谱同时测定高纯硼酸中痕量阴离子的检测方法.样品经水溶解后,通过阀切换技术,使用蠕动泵和IonPac TAC-ULPI超低压浓缩柱,消除基体中硼酸根的干扰,同时在线富集样品中的阴离子,最后使用IonPac AS15分析柱进行分离.在20～500μg/L浓度范围内,7种常见阴离子的工作曲线的线性相关系数r均优于0.995,对硼酸样品进行加标,7种阴离子的平均回收率为90%～106%.该方法可应用于高纯硼酸中痕量阴离子的检测.     

Determination of indium in high purity antimony by electrothermal atomic absorption spectrometry (ETAAS) using boric acid as a modifier

The use of boric acid as a modifier for the determination of trace amount of indium in high purity antimony by electrothermal atomic absorption is described. It was found that the negative influence of the hydrofluoric acid, used for the digestion could not be eliminated by using stabilized temperature platform furnace (STPF) alone. Due to the high dissociation energy (D₀ = 506 kJ mol⁻¹) of indium fluoride, it is difficult to dissociate in the gas phase and hence is lost. In presence of HF (used for the dissolution of antimony), the universal Pd-Mg modifier does not work satisfactorily. Additionally, rising corrosion and reduced tube lifetime were observed when the acid digested (HF-HNO₃) antimony solution was injected in to the platform. Improvement in platform life and elimination of interferences were achieved by the addition of boric acid as a chemical modifier together with ruthenium coating of the platform. Corrosive changes of the transversely heated graphite atomizer (THGA) platform surface were examined by scanning electron microscopy. The standard addition method was applied. A characteristic mass of 36 pg was obtained. The detection limit of the proposed method is around 0.04 μg g⁻¹. The developed method was applied to the determination of indium in real samples. The data obtained by this method were in good agreement with those obtained by ICP-MS.     

Thermodynamics of aqueous solutions of boric acid

Vapor pressures of aqueous solutions of boric acid over a wide range of acid concentrations were measured from 40 to 100°C. The results, together with solubility data taken from the literature, can be described with a thermodynamic model which uses the Wilson equations to express the activity coefficients of water and boric acid. Only three temperature independent adjustable parameters are required; one of these represents the entropy of fusion of boric acid, data which are not available in the literature.     

Determination of traces of rubidium in high purity cesium chloride by electrothermal atomic absorption spectrometry (ETAAS) using boric acid as a modifier

The use of boric acid as a modifier for the determination of trace amount of rubidium in high purity cesium chloride matrix by electrothermal atomic absorption is described. It was found that the negative influence of the chloride matrix could not be eliminated using stabilized temperature platform (STPF) alone. Due to the high dissociation energy (D₀ = 427 kJ mol⁻¹) of rubidium chloride, it was difficult to dissociate in the gas phase and hence is lost. Elimination of interferences was achieved by the addition of boric acid as a chemical modifier. Diluted cesium chloride samples (5%, m/v) were analyzed applying the standard addition method. The characteristic mass of 24 pg was obtained. The detection limit of the proposed method is around 26 ng g⁻¹. The developed method was applied to the determination of traces of rubidium in high purity cesium chloride samples. The data obtained by this method were in good agreement with those obtained by other independent method like FAAS.     

Determination of the hydrogen content in Nigeria palm oil by the neutron moderation method

The thermal neutron moderation analysis facility at the Institute of Experimental Physics, Debrecen, Hungary has been used to determine the weight percent of total hydrogen content in Nigerian palm oil. The facility utilizes the fast neutron moderation technique in which the intensity of reflected thermalized neutrons is proportional to the hydrogen content of the sample exposed to fast neutrons. Using a 100 cm³ sample the total hydrogen content in the oven-dry palm oil sample was found to be 12.0±0.1% within a measuring time of 5 minutes. The method is fast and can be used in plant quality control where the hydrogen content must be determined within specific limits.     

Determination of cadmium in zinc ores by thermal neutron absorption analysis

A method has been developed for routine determination of cadmium in zinc ores by thermal neutron absorption analysis, based on the attenuation of a thermal neutron flux passing through a neutron absorbing material. The thermal neutron flux is related to the⁵²V-activity induced in a vanadium detector, surrounded by pellets pressed from a mixture of powdered material with graphite. Besides cadmium, also the major constitutents zinc, iron and sulfur contribute significantly to the total attenuation of the thermal neutron flux. Calibration lines for these elements are worked out. All irradiations are carried out for 200 s in the partially thermalized neutron flux of a 5 Ci²²⁷Ac—Be isotope neutron source. After a decay of 30 s, the⁵²V-activity of the vanadium detector is measured for 400 s with a NaI(T1) scintillation detector. The analysis sequence, including the computation of the results from the counting data, is automated by means of a LSI—11 microprocessor with 12K×16 bit memory. Zinc ores, containing 0.02 to 1.45% cadmium, have been analyzed with a precision ranging from 12.6% to 0.54% relative. As a test for the reliability of the method, two NBS standard reference materials were analyzed in the same way as the zinc ore samples.     

Effect of boric acid on tetrafluoroborate ion hydrolysis in solutions of tetrafluoroboric acid

The presence of boric acid in tetrafluoroboric acid solutions enhances the BF₄^- ion hydrolysis. An increase of the boric acid content in a 32% HBF₄ solution from 0.1% to 3.8% is accompanied by a simultaneous increase of the degree of hydrolysis from 4.8% to 30.5%.     

Determination of the bitumen content in asphalt concrete using a neutron reflection method

A neutron physical method for the fast, nondestructive determination of the bitumen content in asphalt concrete has been developed. The determination is performed on cylindrical asphalt concrete samples containing desiccated rubble matrix. Using samples of ～1000 g and measuring times of 20 min, the reproducibility of the bitumen determination is ±0.15 w%, the sensitivity is 3·10^?3 g/g.     

石墨炉原子吸收测定模拟体液中的镍

人工关节置换手术的出现是外科手术治疗软骨病损的一次巨大的进步。但人工关节假体的后期松动是长期困扰其发展的难题。镍钛合金人工关节假体材料在体液中的腐蚀与磨损,以及磨损颗粒引起周围组织的异物反应,是造成晚期关节假体松动的主要原因。另一方面,镍钛合金植人体在体液腐蚀下释放的镍离子对人体有害,而且还可能致癌。因此,对镍钛合金进行表面改性,以提高其耐磨与耐腐蚀性能很有必要。     

Determination of boron in glass by neutron transmission method

Neutron transmission method has been used for the determination of boron in borosilicate glasses. The method is sensitive and rapid to control the spatial homogeneities of glass-product in the melting furnace.Dedicated to Academician J. Csikai on his 60th birthday.This work was supported by the National Foundation for Research (Contact No. 259).     

Separation of fission and corrosion products from boric acid solutions by solvent extraction

Extractive purification of boric acid from radioactive corrosion and fission products dissolved in aqueous solutions modelling nuclear reactor coolants has been studied. Aliphatic 1,3-diols containing 8 and 9 carbon atoms per molecule were used as extractants fro boric acid. The behaviour of some representative corrosion and fission products as well as various factors affecting their distribution between the organic and aqueous phases have been investigated under the conditions of boric acid extraction. Conditions for the effective separation of boric acid from most of the radioactive contaminants are presented.     

Determination of structures of cupric-chloro complexes in hydrochloric acid solutions by UV-Vis and X-ray absorption spectroscopy

Structural Chemistry - Ultrahigh-purity metals are indispensable to understanding the nature of materials, but the purity of contemporary metals is insufficient for determining their intrinsic...     

Determination of water in zeolites by a neutron reflection method

Water content in zeolites has been determined by an improved neutron reflection method using a Pu-Be neutron source of 10⁶ n·s^–1 intensity and a BF₃ counter. It was found that the water content of different types of zeolites collected in Hungary varies between 9 and 12 wt.%. The standard deviation of the determination does not exceed 0.5 wt.%. The matrix effect on the sensitivity and accuracy was also studied. An approximate relation is given between the count rate and the neutron physical parameters of the samples.     

高效液相色谱法测定松针中莽草酸的含量

松针为我国传统中药,<本草纲目>曰:松针,味苦温、无毒,久服令人不老,轻身益气,主治风湿疮,生毛发,安五脏,守中,不饥,延年[1].历代均入药用,民间用于治疗神经衰弱、维生素丙缺乏症、营养性水肿、风牙肿痛、阴囊湿痒、腰痛、跌打损伤和预防钩虫病[2].现代临床医学上常用以治疗慢性气管炎、预防流脑和感冒.     

Determination of nickel in finished product alloys by instrumental neutron activation analysis and spectrophotometry

Nickel contents in different finished product alloys were determined using a k ₀-based internal monostandard instrumental neutron activation analysis (IM-INAA) method. Five stainless steels (SS) and three high nickel alloys were analyzed by IM-INAA. BCS CRMs 225/1 (low alloy steel) and 466 (austenitic SS) and NIST SRM 247 (high Ni alloy) were analyzed to evaluate the accuracy of the method. The results of CRMs and SS were found to be in good agreement with certified or specified values. The Ni contents in the high nickel alloys were also determined by relative method of NAA for verification. Nickel contents in BCS CRM 466 and SS 316M were determined by UV–Visible spectrophotometry and the values were found to be in good agreement with IM-INAA results.     

Determination of zinc in high purity bismuth by thermal neutron activation

A neutron activation analysis for the determination of zinc in bismuth was developed. After irradiating the samples for 44 days at 4·10¹¹n/cm²/sec, zinc was separated quantitatively by hexone extraction and precipitation as quinaldate. The sensitivity of the method was estimated as 0.05 p.p.m. No zinc could be detected in the high purity bismuth samples. An addition method of analysis showed that the precision was 1.2%.     

Determination of uranium in salt solutions containing high levels of lanthanides via epithermal neutron activation analysis

Epithermal Instrumental Neutron Activation Analysis has been used to measure the concentration of uranium in eutectic salt solutions in support of a research program in which the actinide elements are separated from rare earths and other fission products using high-temperature electo-deposition. The uranium response over three decades in concentration follows a negative power function; and high concentrations of samarium interfere with the determination of uranium but can be accurately corrected. The EINAA method was successfully used to analyze NIST SRM 278 Obsidian and NIST SRM 1566a Fly Ash.     

Determination of copper impurities in nickel and cobalt salts by atomic absorption spectroscopy

Summary A method is described for the rapid determination of traces of copper in the ppm range in cobalt and nickel salts. The % standard deviation for the analysis is reported as 3.4 to 3.7 for aequous solutions and 4.8 to 5.0 for carbon tetrachloride sprayed directly into the flame after extraction.

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Zusammenfassung Ein Verfahren zur raschen Bestimmung von Kupferspuren im ppm-Bereich in Kobalt- und Nickelsalzen wurde beschrieben. Die Standardabweichung in wäßrigen Lösungen beträgt 3,4 bis 3,7%, bei unmittelbarem Versprühen der Tetrachlorkohlenstoffextrakte in die Flamme 4,8 bis 5,0%.