A new hydrometallurgical process for extracting rare earths from apatite using solvent extraction with P-350

In this paper, a new process is proposed to recover rare earths from nitric acid leaching of apatite without interfering with the normal route for fertilizer production using solvent extraction with dimethyl heptyl methyl phosphonate CH3P(O)(OC8H17)(2) (P-350, B). In the present work, the leaching conditions are studied. In selected condition, apatite was dissolved in 20% (v/v) nitric acid solution at 60-70 degrees C while agitating. The most suitable acidity for extraction is 0.4 M HNO3. More than 98% of rare earths in apatite can be recovered using countercurrent extraction process with six stages when phase ratio = 0.5, and defluorination is unnecessary. The influences of phase ratio, stage number, acidity and salting-out agent on extractabilities Of P-350 are studied. The results show that rare earths can be separated with P-350 from Ca, P, Fe and other impurities. Mixed rare earth oxides (REO) of which purity is more than 95% with yield over 98% can be obtained.

KMgF_3及KMgF_3∶Eu~(2+)晶体的射线辐照效应

KMgF3∶Eu晶体中Eu3+→Eu2+的转换率在低浓度掺杂时接近100%,完全转换的饱和掺杂摩尔分数为0.29%.实验条件下,KMgF3晶体的X射线1 h辐照损伤可在约100 h后恢复;KMgF3∶Eu2+晶体经X射线辐照后,360 nm锐峰发射强度略有降低.不同剂量的γ射线辐照,KMgF3晶体热释光曲线的各个温度峰强度变化明显不同,即使小剂量辐照,造成的损伤也较难恢复,如γ射线辐照剂量为103Gy时,辐照损伤的恢复时间约需30 d.KMgF3∶Eu2+晶体360 nm锐峰发射强度随γ射线辐照剂量增大而呈线性降低.

Simultaneous determination of tramadol and lidocaine in urine by end-column capillary electrophoresis with electrochemiluminescence detection

Tramadol and lidocaine, used as analgesic and local anesthetic in surgery, are partly excreted by kidney. For the first time, we developed a simple and sensitive method, based on capillary electrophoresis with electrochemiluminescence (ECL) detection by end column mode without joint to monitor tramadol and lidocaine in urine. To eliminate the influence of ionic strength of urine sample, analytes were extracted by ether. Tripropylamine (TPA) was used as internal standard. ne recoveries of tramadol and lidocaine were between 94% and 97% at different levels. The method exhibited the linear range for the tramadol and lidocaine from 1.0 X 10(-7) to 1.0 X 10(-4) mol/L with correlation efficient of 0.998. The relative standard deviation (RSD) was 2.9% and 2.7% (n = 8) for tramadol and lidocaine, respectively. The limit of detection (LOD) was 6.0 x 10(-8) mol/L and 4.5 x 10(-8), mol/L (S/N = 3) for tramadol and lidocaine, respectively. The application for detecting tramadol and lidocaine in urine of patients showed that the method was valuable in clinical and biochemical laboratories for detecting tramadol, lidocaine and other tertiary amine pharmaceuticals for various purpose, such as metabolism investigation.

流动注射电化学发光法测定半胱氨酸和谷胱甘肽

采用流动注射分析技术研究了半胱氨酸和谷胱甘肽对鲁米诺微弱电化学发光的增敏行为。对影响电化学发光的各因素进行了试验和探讨 ,提出了可能的反应机理 ,并建立一种电化学发光测定半胱氨酸和谷胱甘肽的新方法。半胱氨酸和谷胱甘肽的浓度在 1 .0× 1 0 - 6 mol/L～ 5 .0× 1 0 - 5 mol/L和 1 .0× 1 0 - 6mol/L～ 2 .0× 1 0 - 5 mol/L之间呈良好的线性关系 ,相关系数分别为 0 .993和0 998,检出限分别为 0 .67μmol/L和 0 .72 μmol/L。对 1 .0× 1 0 - 5mol/L的半胱氨酸和谷胱甘肽进行 1 1次平行测定 ,相对标准偏差分别为 4.5 %和 3.7%。

New technique for capillary electrophoresis directly coupled with end-column electrochemiluminescence detection

capillary electrophoresis (CE) is characterized. A 300 mum diameter Pt working electrode was used to directly couple with a 75 mum inner diameter separation capillary without an electric field decoupler. The hydrodynamic cyclic voltammogram (CV) of Ru(bpy)(3)(2+) showed that electrophoretic current did not affect the ECL reaction. The presence of high-voltage (HV) field only resulted in the shift of the ECL detection potential. The distance of capillary to electrode was an important parameter for optimizing detection performance as it determined the characteristics of mass transport toward the electrode and the actual concentration of Ru(bpy)(3)(2+) in the detection region. The optimum distance of capillary to electrode was decided by the inner diameter of the capillary, too. For a 75 mum capillary, the working electrode should be placed away from the capillary outlet at a distance within the range of 20-260 mum. The effects of pH value of ECL solution and molecular structure of analytes on peak height and theoretical plate numbers were discussed. Using the 75 mum capillary, under the optimum conditions, the method provided a linear range for tripropylamine (TPA) between 1 x 10(-10) and 1 X 10(-5) mol/L with correlation coefficient of 0.998. The detection limit (signal-to-noise ratio S/N = 3) was 5.0 x 10(-11) mol/L. The relative standard deviation in peak height for eight consecutive injections was 5.6%. By this new technique lidocaine spiked in a urine sample was determined. The method exhibited the linear range for lidocaine from 5.0 x 10(-8) to 1.0 X 10(-5) mol/L with correlation efficient of 0.998. The limit of detection (S/N = 3) was 2.0 x 10(-1) mol/L.

Capillary electrophoresis with solid-state electrochemiluminescence detector

We report capillary electrophoresis coupling to a solid-state electrochemiluminescence (ECL) detector for the first time. The solid-state ECL detector was fabricated by immobilizing the ECL reagent tris(2,2'-bipyridyf)ruthenium (TBR) in poly-(p-styrenesulfonate)-silica-poly(vinyl alcohol) grafting 4-vinylpyridine copolymer films. The excellent stability of the solid-state ECL detector in the phosphate solution satisfied application in CE. The CE with solid-state ECL detector system was characterized using tripropylamine (TPA) and proline. The influences of detection potential, the concentration of TBR in the film, and pH value of ECL buffer were investigated. The linear range for TPA and proline was 0.005-10 muM and 5-10 mM with correlation coefficients of 0.997 and 0.998, respectively. The detection limit (signal-to-noise ratio S/N = 3) was estimated to be 0.002 and 2.0 muM for TPA and proline, respectively. The relative standard deviations for 1.0 pm TPA and 1.0 mm proline were 8.7% and 7.5% with theoretical plate numbers of 70 000 and 16 000, respectively. Compared with the CE-ECL of TBR in aqueous solution, the CE coupling with solid-state ECL detector system gave the same sensitivity of analysis.

Crystal structure of a luminescent complex Sm(HTH)(3)Phen

The crystal structure of Sm(HTH)(3)Phen [HTH: 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione, Phen: 1,10-Phenanthroline] has been determined by single crystal X-ray diffraction and the coordination geometry of Sm atom is a dodecahedron. The complex can give the characteristic luminescence of Sm3+ upon UV excitation.

Electrochemiluminescence of tris(2,2 '-bipyridyl)ruthenium (II) ion-exchanged in polyelectrolyte-silica composite thin-films

The organic-inorganic hybrid, PSS-silica composite material was developed for the immobilization of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) on glassy carbon electrode via ion-exchange (PSS stands for poly(sodium 4-styrene-sulfonate)). The electrochemiluminescence (ECL) and electrochemistry of Ru(bpy)(3)(2-) immobilized in the composite thin films have been investigated with tripropylamine (TPA) as the coreactant. The immobilized Ru(bpy)(3)(2-) underwent a surface process. The modified electrode was used for the ECL detection of TPA and showed high sensitivity. Detection limit was 0,1 mumol L-1 for TPA (S/N = 3) with a linear range from 0.5 mumol L-1 to 5 mmol L-1 (R = 0.998), Moreover, the resulting modified electrode was stable over six months and the good stability may be due to the strong interaction between Ru(bpy)(3)(2-) and the high ion-exchange able PSS-silica composite films on GCE. Compared with other materials. the PSS-silica composite films containing incorporated Ru(bpy)(3)(2-) showed improved sensitivity and long-term stability, Thus, such composite thin film can be a promising material for the construction of ECL sensor.

Preparation, characterization, and crystallization of naphthalene-labeled polypropylene

Naphthalene-labeled polypropylene (PP) was prepared by melt reaction of maleic anhydride-grafted-polypropylene (PP-g-MA) with 1-aminonaphthalene in a Barabender mixer chamber. The structure of the product was analyzed with fourier transform infrared (FT-IR), ultraviolet (UV) and fluorescence. The results showed that naphthyl groups grafted onto the PP molecular chains through the imide bonds formed between MA and 1-aminonaphthalene. The content of the chromophores was 1.8 X 10(-4) mol g(-1) measured by elemental analysis. Isothermal crystallization behavior was studied by differential scanning calorimeter (DSC). Labeled PP had a higher crystallization rate than PP-g-MA. Wide-angle X-Ray diffraction (WAXD) analysis revealed that labeled PP had higher crystallinity than PP-g-MA.

Multilayer assemblies of tungstodiphosphate anions on 1,7-diaminoheptane modified glassy carbon electrode and the electrocatalytic reduction to iodate

1,7-Diaminoheptane (DAH) had been covalently grafted on glassy carbon electrode by amino cation radical formation, which resulted in a stable cationic monolayer under proper pH conditions. Dawson-type tungstodiphosphate anion, P2W18O626- and small molecule, Ru(NH3)(6)(3+) were alternately assembled on the DAH modified electrode through layer-by-layer electrostatic interaction. Thus-prepared multilayer film had been characterized by cyclic voltammetry and X-ray photoelectron spectroscopy. The P2W18O626- multilayers exhibit high electrocatalytic response and sensitivity towards the reduction of iodate. With the increase of the number of P2W18O626- the catalytic current was enhanced and the catalytic potential shifted positively. Iodate in table salt was determined at the modified electrode containing three layers of P2W18O626- with satisfactory results. The multilayer electrode is promising as an electrochemical sensor for the detection of trace iodate.

Electrochemiluminescent determination of perchlorate by solvent extraction in the presence of Ru(bpy)(3)(2+)

A novel method for the highly sensitive determination of perchlorate was proposed. It was based on solvent extraction in the presence of Ru(bpy)(3)(2+) followed by Ru(bpy)(3)(2+) electrochemiluminescent determination. A linear calibration was obtained over the range of 0.1 to 10 mu mol l(-1) with a correlation coefficient of 0.998. The detection limit (S/N = 3) was 5.0 x 10(-8) mol l(-1). The relative standard deviation for 10 replicates of 1 mu mol l(-1) perchlorate was 1.6%. Interference studies suggest that this method is selective for the determination of perchlorate. Application of this method to the highly sensitive determination of other anions is suggested. (C) 1999 Elsevier Science S.A. All rights reserved.

异丙基磷酸单(1-已基-4-乙基)辛酯萃取分离锆、钍、钛、铁、镥及其机理

本文通过异丙基膦酸单(1-己基-4-乙基)辛酯在硫酸介质中对Zr~(4+)、Th~(4+)、Ti~(4+)、Fe~(3+)、Lu~(3-)的萃取平衡研究,探讨了Zr~(4-)与其它离子分离的可能性,提出了萃取Zr~(4-)的三种反应机理,并计算了萃取反应平衡常数和热力学函数.

阳离子交换型聚合物AQ薄膜修饰碳纤维电极及伏安行为

本文成功地制备了Eastman-AQ-55D聚合物修饰碳纤维电极,用循环伏安法探讨了一些实验参数的影响,并对Ru(NH_3)_6~(3+)、甲基紫精进行了分析,结果表明,AQ-55D修饰的微电极稳定性好,修饰方法简单,灵敏度和选择性都有一定的提高,Ru(NH_3)_6~(3+)、甲基紫精的峰电流与浓度在1.2×10~(-6)～1.2×10~(-5)mol/L、1.7×10~(-6)～1.4×10~(-5)mol/L范围内呈线性关系,其相关系数分别为0.999、0.998.利用此电极测定了几种离子在膜中的扩散系数.

褐藻两个光系统的色素-蛋白质复合物的分离及特性研究

以褐藻裙带菜(Undaria pinnatifida)、萱藻(Scytosiphon lomentarius)、海蒿子(Sargassum confusum)、叉开网地藻(Dictyopteris divaricata)、海带(Laminaria japonica)、囊藻(Colpomenia sinuosa)、鼠尾藻(Sargassum thunbergii)、水云(Ectocarpus confervoides)为材料，对其色素-蛋白质复合物的分离技术及其特性进行了系统研究。通过对裙带菜色素-蛋白质复合物分离技术及其影响因素的研究，确立了褐藻的PAGE分离方法。采用Tris-Gly电泳分离系统，以非离子去污剂DMG或DIG为增溶剂(DMG: Chl=20: 1, DIG: Chl=50: 1, 4 ℃增溶1 h)，10%的分离胶浓度，丙烯酰胺与甲叉双丙烯酰胺的比例为30: 0.8,从裙带菜中成功地分离出8条含色素的蛋白质复合物带。采用Anderson命名系统，以高等植物菠菜为参照，将其命名为CPIa, CPI, CPa, LHC_1, LHC_2, LHC_3, LHC_4和LHC_5。游离色素较少。通过对三种褐藻的色素-蛋白质复合物的表观分子量测定、光谱学研究以及对裙带菜色素-蛋白质复合物的多肽组成分析，揭示了褐藻各种色素-蛋白质复合物的特征。CPIa是褐藻分子量较大的PSI复合物，为墨角藻黄素-叶绿素 a/c-蛋白质复合物。CPI是褐藻的PSI核心复合物，为P700-叶绿素 a-蛋白质复合物。CPa是褐藻的PSII复合物，为墨角藻黄素-叶绿素 a/c-蛋白质复合物。其余5条为捕光色素-蛋白质复合物，LHC_1和LHC_3是墨角藻黄素-叶绿素 a/c-蛋白质复合物，LHC_2, LHC_4和LHC_5是叶绿素 a/c-蛋白质复合物。根据裙带菜色素-蛋白质复合物的多肽分析结果并与高等植物比较，提出褐藻PSI和PSII的结构模型。褐藻PSI和PSII的反应中心多肽与高等植物相同，捕光复合物明显区别。褐藻LHCI和LHCII的多肽组成相同，都是由单一的20 kDa多肽组成。褐藻叶状体、叶绿体、类囊体膜和PSI复合物的77 K 荧光发射光谱具有特异性，缺少高等植物PSI特征的730 nm 荧光峰。叶状体的77 K 荧光发射光谱按荧光主峰的波长分为两种类型，一种类型的荧光主峰在690 nm，另一种类型的在705-720 nm。三种褐藻PSI复合物的77 K 荧光发射光谱相同，有两个分别们于680 nm和715 nm 的发射峰。褐藻的77 K 荧光特异是由PSI的结构决定的。根据褐藻PSI复合物的荧光特性以及去污剂增溶动力学分析结果，推动F715来自褐藻核心色素-蛋白质复合物，F680来源于PSI复合物中的捕光复合物。褐藻PSI复合物中缺少高等植物发射730 nm 荧光的LHCIb复合物的能量传递模型。

Analysis of the monosaccharide composition of fucoidan by precolumn derivation HPLC

We developed an HPLC method for analysis of the monosaccharide composition of fucoidans. The fucoidan was hydrolyzed into monosaccharides with 2 mol/L trifluoroacetic acid. Using ribose as the internal standard, the monosaccharide derivatives, obtained with 1-Phenyl-3-methyl-5-pyrazolone (PMP), were separated by reverse-phase HPLC using a gradient elution process, and monitored by ultraviolet detection at 245 nm. In the concentration range of 0.1-2.0 mmol/L, the peak area of each monosaccharide had a good linear relationship with its concentration (r(2)> 0.998). The average recoveries of mannose, rhamnose, glucuronic acid, glucose, galactose, xylose, and fucose were 86.2%, 95.1%, 62.5%, 102.0%, 94.8%, 66.6%, and 105.1%, respectively. This method was accurate and had good reproducibility and could be used to determine the monosaccharide contents of fucoidans.