Liquid-Liquid Extraction, Separation, Preconcentration, and ICP-AES Determination of Lanthanum and Cerium with N-Phenyl-(1,2-methanofullerene C60)61-formohydroxamic Acid

A novel method for liquid-liquid extraction, separation, preconcentration, and simultaneous trace determination of cerium(IV) and lanthanum(III) with N-phenyl-(1,2-methanofullerene C₆₀)61-formohydroxamic acid (PMFFA) is reported. Lanthanum and cerium are extracted at pH 8.5 and 9.5, respectively in chloroform and recovered from monazite sands in the presence of thorium, uranium, and large number of cations and anions in high purity (99.98%). The extraction mechanism is investigated. The influence of PMFFA, pH, diverse ions, and temperature on the distribution constants of lanthanum and cerium was examined. The overall stability constants (log β₂K_e) and extraction constants (K_ex) for lanthanum(III) are 22.50 and 5.0 × 10^-9, respectively and for cerium(IV) are 21.51 and 3.9 × 10^-9, respectively. Lanthanum(III) gives a colourless complex with PMFFA which is extracted into chloroform having molar absorptivity 5.5 × 10⁴ L mol^-1 cm^-1 at 395 nm, and Beer's law 0.12-2.52 µg mL^-1, while cerium(IV) forms a red coloured complex, λ_max 460 nm, molar absorptivity 1.5 × 10⁴ L mol^-1 cm^-1, and Beer's law 0.46-9.26 µg mL^-1. For trace determination the extracts were directly inserted into the plasma for inductively coupled plasma atomic emission spectrometry ICP-AES measurements of lanthanum and cerium which increases the sensitivity 60 folds and obey Beer's law in the range, 2.1-37.5 ng mL^-1 for lanthanum and 9.2-186.4 ng mL^-1 for cerium. The method is applied for the determination of lanthanum and cerium in real and standard samples, sea water, and environmental samples.     

Poly(β-Styryl)-(1,2-Methanofullerene-C60)-61-Formo Hydroxamic Acid for the Solid Phase Extraction, Separation and Preconcentration of Rare Earth Elements

A new fullerene derivatives poly(β-styryl)-(12-methanofullerene-C₆₀)-61-formo hydroxamic acid has been synthesized and applied for the solid phase extraction, separation, preconcentration and ICP-MS determination of Ce, La, Pr, Nd, Sm and Gd. The introduction of the fullerene moiety into poly(β-styryl)-hydroxamic acid enhances its reactivity, chemical stability and recycled for their determination. The various parameter, viz. kinetics of sorption, breakthrough studies, effect of eluents, etc., have been studied. The influence of several diverse ions is also discussed. The proposed method has been applied for the sequential chromatographic separation of rare earths in the presence of each from rocks, monazite sand and in environmental samples.     

A Rapid Method for the Determination of Gold in Rocks, Ores and Other Geological Materials by F-AAS and GF-AAS After Separation and Preconcentration by DIBK Extraction for Prospecting Studies

A solvent extraction method using diisobutyle ketone (DIBK) is designed for the accurate and precise estimation of very low concentrations of gold in rocks, ores and other geological samples. 30?g sample was digested using aqua regia after roasting and gold content was extracted into DIBK phase consisting of Aliquat? 336 and estimated by flame atomic absorption spectrometer (F-AAS). Samples having gold concentration <0.1???g/g were estimated using graphite furnace atomic absorption spectrometer (GF-AAS). Results of DIBK extraction were compared to those obtained by other well established methods, such as classical Pb-fire assay and methyl isobutyl ketone (MIBK)-AAS methods. Comparison was also made with results obtained by the direct determination of gold by inductively coupled plasma mass spectrometry (ICP-MS) technique. The analytical results for international gold reference materials measured by the proposed method were in close agreement with those obtained by other well established methods and recommended values. Detection limits (20?ng/g by F-AAS, 0.1?ng/g by GF-AAS and 0.01?ng/g by ICP-MS) of gold (3????× total procedure blank) is very low and could be further improved by using high pure acids and other reagents.     

Selective Supercritical Fluid Extraction of Uranium(VI) using N-Phenyl-(1,2-Methano-Fullerene C60)61-Formohydroxamic acid and Simultaneous On-line Determination by Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS)

Uranium(VI) is extracted with N-phenyl-(1,2-methano-fullerene C₆₀)61-formohydroxamic acid, PMFFHA, in dichloromethane by supercritical carbon dioxide (SF-CO₂)-dichloromethane (modifier) medium. A 2.0 µL aqueous uranium is extracted accurately and also preconcentrated in an especially designed extraction vessel of 80 µL capacity. The extracted microdrop orange-red colored uranium(VI)-PMFFHA complex in dichloromethane was online measured by fiber optics spectrometry and ICP-MS. The distribution ratio (D_UO2²⁺) of U(VI) was determined. The slopes of log D_UO2²⁺ versus PMFFHA concentration plot, the extracted species both in SF-CO₂ extraction (SFE) and the solvent extraction (SE) were determined to be 2.0 as UO₂(PMFFHA)₂ complex. The uranium is determined as low as 0.10 ng mL^-1 in presence of several cations and anions. The effect of diluents, modifier concentration, temperature and pressure on the extraction and separation of uranium was studied. The uranium is determined in human blood serum, natural water, seawater, standard samples and also in monazite sand. The PMFFHA has been successfully used as carrier for the selective and efficient transport of uranium(VI). The feed comprised of a solution of uranium(VI) and aqueous solution of diverse cations and anions in pH 4.5, while 1M HNO₃ was used as a stripping agent in the receiving compartment of permeated cell. Maximum transportation was observed for 12 minutes with t_1/2 equal to 6.3 min. The uranium(VI) was determined in presence of uranium(IV).     

一种新型萃取装置及其在水样挥发酚测定中的应用

本文介绍一种新型萃取装置,由磁力搅拌器、三角烧瓶和经改造的活塞组成。此装置已用于挥发酚的测定中。大量实验数据表明,该装置优于常规分液漏斗,克服了使用分液漏斗中常见的易漏、重现性差、工作强度大等缺点。其准确度,重现性,工作曲线相关性均较好,是一种可以取代分液漏斗,用于各类常规分析的理想玻璃仪器。     

Extraction of Thorium(IV) with N-Methyl-N,N,N-trioctylammonium Chloride from Monazite Acidic Leach Liquor and Its Use for Spectrophotometric Determination

N-Methyl-N,N,N-trioctylammonium chloride was applied for selective extraction and separation of thorium. The Th extraction and stripping conditions were experimentally optimized. 0.75 M N-methyl-N,N,N-trioctylammonium chloride was found to be suitable for the Th separation. The extraction of Th(IV) form monazite is an exothermic process. The optimum parameters were applied to the spectrophotometric determination of Th using Thoron I at λ_max = 540 nm with accurate results. From the stripped liquor (1 M HNO₃), Th was precipitated as thorium oxalate for technological application. Thus, marketable pure thorium product was prepared in addition to uranium and rare earth concentrates.

     

用腐植酸树脂分离富集-火焰原子吸收法测定电镀液中痕量铅

采用酚醛树脂对天然腐植酸交联固化,制备成腐植酸酚醛树脂.采用火焰原子吸收分光光度法(FAAS)研究了腐植酸酚醛树脂对铅的吸附性能.结果表明,腐植酸酚醛树脂对铅有较强的吸附能力,吸附量受介质pH值的影响,当pH值大于3.0时,铅可被定量吸附,最大吸附量可达17.28 mg/g.吸附于树脂上的铅可以用0.1 mol/L的HNO3溶液完全解脱.以FAAS法为检测手段,对镀铬液中痕量铅进行分离富集,建立了电镀液中痕量铅的测定新方法,应用于实际样品的测定,结果满意.     

电位滴定法测定润滑油酸值不确定度评估

利用电位滴定法测定润滑油中酸值,建立了电位滴定法测定酸值的数学模型,分析了不确定度来源,评定了电位滴定法测定润滑油酸值的不确定度。通过重复性试验,测定齿轮油酸值为0.706 mg/g,对该结果进行了A类和B类不确定度评定,当包含因子为k=2置信水平为95%时, 扩展不确定度为0.010 mg/g。     

C60H18, C60H36 and C70H36 Fullerene Hydrides: Study by Methods of IR,NMR, XPS,EELS and Magnetochemistry

Abstract

Fullerene hydrides of C₆₀H₁₈, C₆₀H₃₆ and C₇₀H₃₆ are studied by using IR, ¹H and ¹³C NMR, X-ray photoelectron and electron energy loss spectroscopies, and magnetochemistry. The comparison of IR and solid state ¹H and ¹³C NMR data for C₆₀H₃₆ with the theoretical ones allows the suggestion that fullerene hydride has a T symmetric structure and contains 4 isolated benzenoid rings located at tetrahedral positions on the surface of a closed skeleton of the molecule. The EELS revealed that the transition from fullerene to the hydride is accompanied by the decrease of the density of valence electrons. Magnetization measurements showed C₆₀H₃₆ to be a ferromagnet. The hydrogenated fullerenes were prepared by transfer hydrogenation procedures involving 9,10-dihydroanthracene. The compositions of the hydrides are determined by field desorption mass-spectral analysis.     

A Novel Non-Invasive Method for Extraction of Geometrical and Texture Features of Wood

Non invasive feature detection in wood based application requires exact discrimination between geometrical edges and texture. It has been found that traditional edge detection algorithms are highly sensitive to noise and texture and produces inferior results with wood. The present work encompasses a micro level reconstruction of Palash and Rosewood by using micro X-rays CT scanner. It also encompasses a new edge detection algorithm using newly constructed Chebyshev polynomial based fractional order differentiator. Transform based method has been used for reconstruction purpose. Newly designed fractional order filter has been applied on these reconstructed images. Chebyshev polynomial based fractional order differentiator has been used for filtering operation. Quadrature Mirror Filter (QMF) concept has been used for design of high pass filter and low pass filter. Preprocessing has been performed by using this filter. Canny edge detection algorithm has been used on this preprocessed image. The algorithm has been tested on two different test cases of wood images a) Palash and b) Rosewood. The effect of relaxation coefficient has also been presented and discussed.     

Low Blank Preconcentration Technique for the Determination of Lead, Copper, and Cadmium in Small-Volume Seawater Samples by Isotope Dilution ICPMS

A simple low-blank method is described for the analysis of Pb, Cu, and Cd in seawater using Mg(OH)(2) coprecipitation and isotope dilution inductively coupled plasma mass spectrometry (ICPMS). Here, 20-40 μL of 9 M aqueous NH(3) is mixed into a 1.3 mL seawater sample spiked with enriched isotopes of Pb, Cu, and Cd. After centrifugation, the supernatant is discarded and the Mg(OH)(2) precipitate dissolved in 100 μL of 5% HNO(3) for ICPMS analysis. This method is simple, accurate, and precise, with detection limits of Pb = 1.3 pM, Cu = 39 pM, and Cd = 5.0 pM and blanks of Pb = 0.62 pM, Cu = 27 pM, and Cd = 6.0 pM. The method is demonstrated by oceanographically consistent profiles of these trace metals at an ocean station in the eastern North Atlantic.     

一种新的模拟电路故障模糊集确定算法

提出了一种在模拟电路故障诊断中故障类模糊集的确定算法．该算法基于测前仿真法,不但同时适用于线性电路和非线性电路,而且可以确定元件模糊组以外的故障类模糊集．算法利用电路仿真故障特征数据计算故障的类间差异矩阵,从而完成故障类模糊集的确定．计算示例验证了该算法的有效性．     

A Novel Apparatus for the Determination of Solubility in Pressurized Metered Dose Inhalers

ABSTRACT

The accurate solubility of salbutamol sulfate, budesonide, and formoterol fumarate dihydrate in hydrofluoroalkane propellant 134a at 25°C for 24 h, are reported. The authors describe a novel reusable in-line pressurized solubility apparatus containing an integral filter holder and a continuous decrimpable valve for the determination of drug/excipients solubility in pressurized metered dose inhalers. The solubility was determined by high-performance liquid chromatography. Solubility of salbutamol sulfate was determined as being below the detection limits while budesonide and formoterol fumarate dihydrate solubility were 23.136 ± 2.951 μg.g^?1 and 0.776 ± 1.023 μg.g^?1, respectively (n?=?3). This novel solubility apparatus offers an improved ease of use and potential higher analytical throughput.     

薄膜阳极系统硫酸电解液中氯离子分析方法的选择

碱性锌镍合金电镀生产中,薄膜阳极系统硫酸电解液中的氯离子含量过高会严重影响阳极的使用寿命,因此快速、准确地分析其含量很有必要.为此,考察了用紫外分光光度(UV)法和离子色谱(IC)法等4种分析方法测定硫酸电解液里氯离子浓度的准确率,确定了最佳的检测方法为紫外分光光度标准加入法-浑浊法.该法前处理简单,反应时间短,能快速有效地监测薄膜阳极系统电解液中氯离子含量,符合实际生产要求.     

ICP-AES法测定斑岩型铜矿石中铜铅锌钼

本文用ICP-AES法测定斑岩型铜矿中的铜铅锌钼。采用盐酸硝酸氢氟酸和高氯酸四种酸混合消化样品。研究仪器的最佳工作参数,用基体一致时测定待测元素来校正基体干扰,分别找出仪器测定的最佳分析谱线进行样品测量。本方法的检出限在0.21?g/g～0.65?g/g。测量结果的相对标准偏差为0.36%～1.8%(n=8),回收率在95%-102.6%之间。     

A Simple and Effective Principle for a Rational Design of Heterogeneous Catalysts for Dehydrogenation of Formic Acid

Efficient and selective dehydrogenation of formic acid is a key challenge for a fuel‐cell‐based hydrogen economy. Though the development of heterogeneous catalysts has received much progress, their catalytic activity remains insufficient. Moreover, the design principle of such catalysts are still unclear. Here, experimental and theoretical studies on a series of mono‐/bi‐metallic nanoparticles supported on a NH₂‐N‐rGO substrate are combined for formic acid dehydrogenation where the surface energy of a metal is taken as a relevant indicator for the adsorption ability of the catalyst for guiding catalyst design. The AuPd/NH₂‐N‐rGO catalyst shows record catalytic activity by reducing the energy barrier of rate controlling steps of formate adsorption and hydrogen desorption. The obtained excellent results both in experiments and simulations could be extended to other important systems, providing a general guideline to design more efficient catalysts.     

A Halogen-Bonded Organic Framework (XOF) Emissive Cocrystal for Acid Vapor and Explosive Sensing,and Iodine Capture

There is a strong and urgent need for efficient materials that can capture radioactive iodine atoms from nuclear waste. This work presents a novel strategy to develop porous materials for iodine capture by employing halogen bonding, mechanochemistry and crystal engineering. 3D halogen-bonded organic frameworks (XOFs) with guest-accessible permanent pores are exciting targets in crystal engineering for developing functional materials, and this work reports the first example of such a structure. The new-found XOF, namely TIEPE-DABCO , exhibits enhanced emission in the solid state and turn-off emission sensing of acid vapors and explosives like picric acid in nanomolar quantity. TIEPE-DABCO captures iodine from the gas phase (3.23 g g⁻¹ at 75 °C and 1.40 g g⁻¹ at rt), organic solvents (2.1 g g⁻¹), and aqueous solutions (1.8 g g⁻¹ in the pH range of 3–8); the latter with fast kinetics. The captured iodine can be retained for more than 7 days without any leaching, but readily released using methanol, when required. TIEPE-DABCO can be recycled for iodine capture several times without any loss of storage capacity. The results presented in this work demonstrate the potential of mechanochemical cocrystal engineering with halogen bonding as an approach to develop porous materials for iodine capture and sensing.     

Influence of Ferrous Sulfate on the Solubility,Partition Coefficient,and Stability of Mycophenolic Acid and the Ester Mycophenolate Mofetil

ABSTRACT

Studies were performed to (1) evaluate whether the presence of iron affected the physicochemical properties of mycophenolate mofetil (MMF) and mycophenolic acid (MPA), and (2) determine whether alteration of these properties was indicative of formation of an MMF–iron complex. The solubility, stability (chemical reactivity), and partitioning properties of MMF and MPA were evaluated over a pH range of 2–7 in the presence and absence of ferrous sulfate. In addition, the solubility and partitioning properties of MMF were assessed after the MMF drug product, CellCept® capsules, was combined with an iron tablet (Fero-Gradumet®, ferrous sulfate, tablets). The results of studies showed that:

• The solubility of MMF in the presence of ferrous sulfate was generally unaffected over a pH range of 2–7; a small increase in solubility was observed in pH 5.2 buffer solution. The solubility of MPA decreased in pH 5.2 and 7.0 buffer solutions.

• Both MMF and MPA were more stable in the presence of ferrous sulfate at pH 2.0; ferrous sulfate had no effect on the stability of MMF and MPA at pH 7.0.

• Overall, the partitioning of MMF and MPA was unaffected by the addition of ferrous sulfate.

• The solubility and partitioning of MMF from CellCept® capsules combined with Fero-Gradumet® (ferrous sulfate) tablets showed a twofold increase in aqueous solubility of MMF as well as increased concentration of MMF in both the n-octanol and aqueous phases, leading to a decrease in the octanol/water partition coefficient due to a reduction in pH of the aqueous phase.

Based on these results, it was concluded that the physicochemical properties of MMF and MPA were generally not affected by the presence of ferrous sulfate. Further, the presence of ferrous sulfate did not suggest the formation of an MMF–iron complex.     

乙酸处理脱铝对丝光沸石结构、酸性质及其催化性能的影响

基于丝光沸石(HMOR)催化合成乙酸甲酯稳定性较差及八元环边袋结构酸性位专一性催化作用的特性, 提出了利用乙酸处理具有八元环-Na和十二元环-H的MOR以制备选择性脱铝及疏通八元环边袋结构技术。采用XRD、²⁷Al-NMR、NH₃-TPD、吡啶红外和N₂吸-脱附等手段对催化剂进行了表征, 分别考察了不同乙酸浓度处理条件对分子筛催化剂骨架结构、酸性质、微孔结构以及催化合成乙酸甲酯性能的影响。结果表明, 通过合适浓度乙酸溶液处理, HMOR分子筛的硅铝比、微孔体积、中值孔径都增大, BJH孔径分布未见明显变化, 乙酸溶液处理脱除了HMOR中十二元环的Al, 最大限度地保留了八元环边袋结构中的Al。改性后的HMOR催化剂二甲醚转化率平稳期由18 h延长至50 h, 催化剂的稳定性能得以改善, 催化剂转化率由45.6%降至43.8%, 催化剂活性略有降低。     

香菇中菌盖和菌柄部分主要氨基酸成分的分析比较

本文应用HPLC法,分别测定香菇菌盖和菌柄部分15种主要氨基酸的含量,其中菌盖为6.26％,菌柄为2.98％。