On-line separation and preconcentration of inorganic arsenic and selenium species in natural water samples with CTAB-modified alkyl silica microcolumn and determination by inductively coupled plasma-optical emission spectrometry

A new, simple, and selective method has been presented for the separation and preconcentration of inorganic arsenic (As(III)/As(V)) and selenium (Se(IV)/Se(VI)) species by a microcolumn on-line coupled with inductively coupled plasma-optical emission spectrometry (ICP-OES). Trace amounts of As(V) and Se(VI) species were separated and preconcentrated from total As and Se at desired pH values by a conical microcolumn packed with cetyltrimethylammonium bromide (CTAB)-modified alkyl silica sorbent in the absence of chelating reagent. The species adsorbed by CTAB-modified alkyl silica sorbent were quantitatively desorbed with 0.10 ml of 1.0 mol l⁻¹ HNO₃. Total inorganic arsenic and selenium were similarly extracted after oxidation of As(III) and Se(IV) to As(V) and Se(VI) with KMnO₄ (50.0 μmol l⁻¹). The assay of As(III) and Se(IV) were based on subtracting As(V) and Se(VI) from total As and total Se, respectively. All parameters affecting the separation/preconcentration of As(V) and Se(VI) including pH, sample flow rate and volume, eluent solution and volume have been studied. With a sample volume of 3.0 ml, the sample throughput was 24 h⁻¹ and the enrichment factors for As(V) and Se(VI) were 26.7 and 27.6, respectively. The limits of detection (LODs) were 0.15 μg l⁻¹ for As(V) and 0.10 μg l⁻¹ for Se(VI). The relative standard deviations (RSDs) for nine replicate determinations at 5.0 μg l⁻¹ level of As(V) and Se(VI) were 4.0% and 3.6%, respectively. The calibration graphs of the method for As(V) and Se(VI) were linear in the range of 0.5–1000.0 μg l⁻¹ with a correlation coefficient of 0.9936 and 0.9992, respectively. The developed method was successfully applied to the speciation analysis of inorganic arsenic and selenium in natural water samples with satisfactory results.     

钒掺杂TiO2/AC负载催化剂的制备及光催化活性

以TiO2为主要成分的光催化剂的研究已日益受到人们的广泛关注[1-6]。但TiO2粉末的回收和流失问题难以解决,固定化TiO2负载催化剂的研制是解决这一问题的有效手段[2-6]。从实际应用的观点看,TiO2的光催化剂活性还有待进一步提高。研究发现,大多数过渡金属离子和少数非金属离子的     

Manipulating OH−-Mediated Anode-Cathode Cross-Communication Toward Long-Life Aqueous Zinc-Vanadium Batteries

The anode-cathode interplay is an important but rarely considered factor that initiates the degradation of aqueous zinc ion batteries (AZIBs). Herein, to address the limited cyclability issue of V-based AZIBs, Al₂(SO₄)₃ is proposed as decent electrolyte additive to manipulate OH⁻-mediated cross-communication between Zn anode and NaV₃O₈ ⋅ 1.5H₂O (NVO) cathode. The hydrolysis of Al³⁺ creates a pH≈0.9 strong acidic environment, which unexpectedly prolongs the anode lifespan from 200 to 1000 h. Such impressive improvement is assigned to the alleviation of interfacial OH⁻ accumulation by Al³⁺ adsorption and solid electrolyte interphase formation. Accordingly, the strongly acidified electrolyte, associated with the sedated crossover of anodic OH⁻ toward NVO, remarkably mitigate its undesired dissolution and phase transition. The interrupted OH⁻-mediated communication between the two electrodes endows Zn||NVO batteries with superb cycling stability, at both low and high scan rates.     

Temperature-dependent dry etching characteristics of III–V semiconductors in HBr- and HI-based discharges

Microwave discharges of HBr/H₂/Ar and H/H₂/Ar with additional do biasing of the sample were used to etch InP, GaAs, and AlGaAs at temperatures between 50–250°C. The etch rates increase by factors of 3–50 and 5–9, respectively, for HBr-and HI-based discharges over this temperature range, but display non-Arrhenius behavior. The etched surfaces became very rough above 100°C for InP with either discharge chemistry due to preferential loss of P, while GaAs and AlGaAs are more tolerant of the elevated temperature etching. The near-surface electrical properties of InP are severely degraded by etch temperatures above 100°C, while extensive hydrogen in-diffusion occurs in GaAs and AlGaAs under these conditions, leading to dopant passivation which can be reversed by annealing at 400°C.     

二安替比林对乙氧基苯基甲烷吸光光度法测定微量V(Ⅴ)

合成了新试剂二安替比林对乙氧基苯基甲烷,并研究了与V(Ⅴ)的显色反应。在磷酸介质中和Mn(Ⅱ)-乳化剂OP的作用下,显色反应的产物为橙黄色,ε为2.90×10~6,λ_(max)=450nm,测定V(Ⅴ)的线性范围为4～32μg·L~(-1)。用于中草药中微量V(Ⅴ)的测定,结果满意。     

V2O5电致变色薄膜的Raman光谱

近年来,通过向过渡金属氧化物薄膜注入Ｌｉ 制作可调节光透过率的电变色器件已越来越引起广泛的重视[1、2].由于Ｖ2Ｏ5薄膜的稳定性差,限制了它在实际中的应用.因此,为了获得变色效率高、稳定性和可逆性能好的Ｖ2Ｏ5薄膜,使用了多种制备方法,如磁控溅射法[3、6]、电化学沉积法[7、8]、溶胶凝胶法[9、10]、旋涂法[11、12]、真空蒸镀法[13、14]等.但是,无论那种方法都要解决Ｖ2Ｏ5本身在Ｈ2Ｏ或醇等的电解质溶液中电致变色时的溶解问题,通常采用控制薄膜的沉积温度或者退火处理来提高薄膜的电致变色性能[3、4、11].为了探明薄膜结构与电致变色…     

First 13C‐NMR Assignments of Betaxanthins

Due to their inherent liability towards highly acidic conditions previously considered to be a prerequisite for data acquisition, betaxanthin structure dereplication by NMR spectroscopy has been scarcely reported and was, hitherto, exclusively based on ¹H‐NMR data interpretation. Applying only slightly acidic conditions, we herein report the first ¹³C‐NMR data of two betaxanthins, i.e., indicaxanthin ( 1 ), isolated from yellow‐orange cactus pear fruits (Opuntia ficus‐indica [L.] Mill . cv. ‘Gialla’), and of miraxanthin V ( 2 ) from yellow Swiss chard petioles (Beta vulgaris L. ssp. cicla [L.] Alef . cv. ‘Bright Lights’), as derived by gHSQC‐ and gHMQC‐NMR experiments and inverse detection.     

Synthesis and Characterization of a Reduced Molybdenum(V) Phosphate, (H_3dien)_2(H_2dien)_2[NaMo_(12)O_(24)(OH)_6-(H_2PO_4)(HPO_4)_5(PO_4)_2]·nH_2O (n = 10.92)

A new reduced molybdenum(V) phosphate (H3dien)2(H2dien)2[NaMo12O24 (OH)6 (H2PO4)(HPO4)5(PO4)2]·nH2O (n = 10.92, dien = diethylenetriamine) has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR and X-ray diffraction. C16H96.84Mo12N12NaO72.92P8 (Mr = 3046.73) crystallizes in the monoclinic system, space group P21/c with a = 13.3575(18), b = 21.907(3), c = 15.654(2) , β = 110.22(2)°, V = 4298.4(10) 3, Dc = 2.354 g/cm3, Z = 2, μ(MoKα) = 1.966 mm-1, F(000) = 2990.4, the final R = 0.0357 and wR = 0.1086 for 8739 observed reflections with I > 2σ(I). It consists of sandwich-shaped cluster anions [Na{Mo6P4}2]10- held together into a three-dimensional supramolecular framework through intermolecular hydrogen-bonding contacts. A probe reaction of the oxidation of acetaldehyde with H2O2 showed that this compound has high catalytic activity in the reaction.     

As（Ⅲ）和As（V）与牛血清白蛋白的结合平衡研究

在模拟动物体生理条件下,研究As（Ⅲ）和As（V）与牛血清白蛋白（BSA）的相互作用．用氢化物发生．超低温捕集塬子吸收分光光度法测定平衡透析后As（Ⅲ）或As（V）的浓度,用Scatchard方法分别处理实验数据,确定结合部位和结合常数．发现当As（Ⅲ）浓度（CAs（Ⅲ）：CBsA≤1：1）较低时,在BSA中有1．3个强结合部位,结合常数为1．7×10^6,为强结合;当As（Ⅲ）的浓度（cAs（Ⅲ）：cBSA≥2：1）较高时,没有明显的特征结合点,表现为弱结合．而As（V）与BSA无任何结合作用．     

Hydrothermal Synthesis,Crystal Structure and Fluorescent Property of a Novel Mo(V) Phosphate [Zn(Mo~v_6P_4O_(31)H_(10))_2(C_4H_(14)N_3)_2]·2C_4H_(13)N_3·8H_2O

1 INTRODUCTION Hydrothermal synthesis of Mo(V) phosphates has allowed various structures, all characterized by the presence of identical clusters with the composition Mo12MP8X62 (X = O, OH) to be stabilized[1～6]. Many Mo(V) phosphates with such clusters have been iso- lated to date. The first compound was discovered by Haushalter and Lai[1] for M = Na with the formula (PPh4)2[(H3O)2NaMo6P4O24(OH)7]?5H2O. Recently, a second type of structure has been observed for M = Na (Na8(…