支撑液膜在线萃取富集流动注射荧光光度法测定水中痕量苯酚

选用无毒性的磷酸三丁酯为流动载体, 煤油为膜溶剂的液膜萃取体系, 建立了支撑液膜在线萃取富集流动注射荧光光度法测定水中痕量苯酚的新方法. 对实验条件进行了优化. 方法的检出限为0.4 μg/L, 线性范围为1～180 μg/L.     

支撑液膜在线萃取富集流动注射分光光度法测定水中的痕量铅

研究了以双硫腙为流动载体,煤油为膜溶剂的支撑液膜萃取体系,建立了支撑液膜在线萃取富集流动注射分光光度法测定水中痕量铅(Ⅱ)的新方法。优化了支撑液膜萃取富集条件,优化结果为:试样pH=6,反萃液柠檬酸浓度为0.5 mol/L,载体双硫腙浓度为0.03%,膜孔径为0.3μm,富集时间为30 m in。在此条件下,方法的检出限为0.2μg/L;线性范围为0.5~100μg/L。应用于自来水、河水和工业污水中铅(Ⅱ)的检测,结果满意。     

在线液膜萃取富集流动注射分光光度法测定水中挥发酚

选用无毒性的磷酸三丁酯为流动载体，煤油为膜溶剂的液膜萃取体系，建立了液膜在线萃取富集流动注射分光光度法测定水中挥发酚的新方法。对实验条件进行了优化，在最优条件下，方法的检出限为0．0007mg/L；线性范围为0．001～0．01mg/L。应用于自来水及河水中挥发酚的检测，结果满意。     

金属离子提取的支撑型液膜稳定性:膜材料研究进展

支撑液膜是一种结合膜材料与萃取体系的高效率分离技术.然而在使用过程中,溶剂与萃取载体从多孔支撑体中流失和多孔膜材料在有机相载体中不稳定,导致支撑液膜通量的衰减或选择性降低,支撑液膜表现为不稳定,目前尚未见工业化的成功案例.本文简要介绍了支撑液膜不稳定机理,从膜材料角度,综述了提高支撑液膜稳定性的方法.重点介绍了液膜凝胶...     

支撑液膜在线萃取富集流动注射分光光度法测定水中痕量苯胺

选用无毒性的磷酸三丁酯为载体，煤油为膜溶剂的支撑液膜萃取体系，建立了支撑液膜在线萃取富集流动注射分光光度法测定河水中苯胺的新方法。对实验条件进行了优化。实验结果表明：在内相pH=2,外相pH=11，膜相组成为15%TBP-85%煤油，富集时间为13min的最优条件下，方法的检出限为0.04mg/L；线性范围为0.1-4mg/L。应用于河水中痕量苯胺的检测，结果满意。     

中空纤维分散液膜富集稀土元素

采用2-乙基己基膦酸单-2-乙基己基酯(HEHEHP)-正庚烷为萃取剂,盐酸为反萃取剂,中空纤维膜作支撑膜,研究中空纤维分散液膜技术富集稀土镱(Yb~(3+))离子。考察了体系物性:反萃分散相中反萃剂浓度、萃取剂浓度、萃取剂与反萃剂体积比、料液相p H值、稀土离子浓度;流体流动状态:反萃分散相与料液相流速变化等因素对富集稀土离子的影响。中空纤维分散液膜富集Yb~(3+)的最佳条件为:萃取剂浓度为0.25 mol/L,反萃取剂HCl浓度为4.00 mol/L,萃取剂与反萃剂体积比为10∶40,料液相p H=2.80,稀土离子浓度为0.025 mol/L。反萃分散相体积流量和料液相体积流量较小时,萃取率随流量的增加呈现逐渐增大的趋势。若两相体积流量过大,反萃过程进行不完全,萃取率反而下降。研究结果表明,中空纤维分散液膜技术可实现稀土离子的有效富集。     

液液萃取-分散液液微萃取-气相色谱-质谱联用测定纺织废水中痕量禁用偶氮染料

建立了液液萃取-分散液液微萃取-气相色谱-质谱联用技术测定纺织废水中痕量偶氮染料的方法。废水中的偶氮染料在碱性条件下经连二亚硫酸钠还原成芳香胺后,先用叔丁基甲醚液液萃取、盐酸反萃进行预浓缩及净化;再以乙腈-氯苯体系进行分散液液微萃取,气相色谱-质谱测定。对前处理条件进行了优化,考察了酸碱度及盐效应对芳香胺萃取效率的影响,结果表明：液液萃取过程中加入30 g NaCl,分散液液微萃取过程中加入1 mL 5 mol/L的NaOH调节体系至碱性才能达到较好的萃取效率。在优化的实验条件下,21种目标物均呈现良好的线性关系,其中13种芳香胺的线性范围为0.05~10 μg/L,7种芳香胺的线性范围为0.05~5 μg/L,2,4-二氨基苯甲醚的线性范围为20~100 μg/L,相关系数为0.996~0.999。20种芳香胺的检出限可达0.05 μg/L,2,4-二氨基苯甲醚检出限为20 μg/L。印染、机织、印花等实际废水加标试验表明,方法的回收率为75.6%~115.1%。该方法富集倍数高,检出限低,适用于纺织废水中痕量禁用偶氮染料的检测。     

平板夹心型支撑液膜萃取体系中La^3＋的迁移行为

在含ＨＥＨ（ＥＨＰ）的平板夹心型支撑液膜萃取Ｌａ＾３＋的体系中，研究了体系传质过程中的渗透系数ｐ及其影响因素。实验证明夹心型与单型支撑液膜的传质理论模型以及料液酸度和反萃液酸度对传质渗透系数的影响基本一致。当体系料液的ｐＨ在３．５￣４．２之间时，体系的渗透系数ｐ趋于稳定；ｐ随反萃液酸度的增加而增大，当反萃液酸度大于４．０ｍｏｌ／Ｌ时，ｐ趋于恒定；比较了用不同材料和厚度的夹心型支撑液膜体系萃取ｌａ２     

气浮络合萃取分离富集L-苯丙氨酸的研究

结合溶剂浮选和络合萃取,提出了气浮络合萃取(floatation complexation extraction)的概念,应用该方法实现了对L-苯丙氨酸的分离富集。在试液的pH为11、NaCl浓度为0.20 mol/L、有机相为80%P204的正己烷溶液、通气流速为40 mL/min、通气时间为60 min的条件下对水相中L-苯丙氨酸进行气浮络合萃取。在分离富集的基础上,用pH<1的HCl水溶液对L-苯丙氨酸进行反萃取,通过紫外和红外光谱分析,确认了分离产物为L-苯丙氨酸。     

电化学液相微萃取-循环伏安法对海带中溴的测定

将液相微萃取与电化学法相结合,建立了快速测定海带中溴含量的电化学液相微萃取-循环伏安法(ELPME-CV).苯甲酸乙酯作为粘结剂组成碳糊电极,同时充当微液膜萃取相与样品溶液接触.在正电位下,溴离子被氧化成溴分子,溴分子经微液膜萃取富集,在负电位下还原溶出.在0.01 ～0.50 mmol/L范围内,溴的还原峰电流与溶液中溴离子浓度成正比,检出限为0.05 mmol/L.测定市售海带中溴的含量为91 μg/g,相对标准偏差为11%.     

HPMBP和二苯胍对Ho~(3+)的协同萃取机理研究

研究了 1-苯基 - 3-甲基 - 4 -苯酰基吡唑酮 - 5(HPMBP)和二苯胍 (DPG)的三氯甲烷溶液对硝酸介质中Ho3+萃取机理。实验结果表明 :在体系Ho3+(～ 10 - 4mol/L)HNO3　NaNO3( μ =0 2 ) /HPMB -DPG -CH3Cl中 ,存在明显的协同效应。利用斜率法测得萃合物的组成为 [HB]+[HoA4 ](HA代表HPMBP ,B代表DPG) ,常温时的萃取平衡常数K =2 7.2 4 ;讨论了协同萃取机理和萃合物的结构。     

Liquid chromatographic determination of nine N-methylcarbamates in drinking water

A multi-residue method for the simultaneous extraction from drinking water using solid-phase extraction on LiChrolut EN [poly(styrene-divinylbenzene), PSDVB] and determination of nine N-methylcarbamate pesticides (NMCs) (aldicarb, its metabolites i.e. aldicarb sulfone and aldicarb sulfoxide and carbaryl, carbofuran, dioxacarb, ethiofencarb, methomyl and propoxur) using reversed-phase liquid chromatography was studied. A 1000-fold pre-concentration was achieved and the method was used for determination of the nine pesticides in water, with limits of detection in the range 3-15 ng L(-1). For all compounds the recoveries determined at the 0.1 and 1 microg L(-1) level generally ranged from 85 to 104% with relative standard deviations (RSD) of 1.4-8.8%.     

Reductive degradation of nido-1-CB8H12 into smaller-cage carborane systems via new monocarbaboranes [arachno-5-CB8H13](-) and closo-2-CB6H8

Treatment of the nido-1-CB8H12 (1) carborane with NaBH4 in THF at ambient temperature led to the isolation of the stable [arachno-5-CB8H13]- (2(-)), which was isolated as Na+[5-CB8H13]-.1.5 THF and PPh4 +[5-CB8H13]- in almost quantitative yield. Compound 2(-) underwent a boron-degradation reaction with concentrated hydrochloric acid to afford the arachno-4-CB7H13 (3) carborane in 70 % yield, whereas reaction between 2(-) and excess phenyl acetylene in refluxing THF gave the [closo-2-CB6H7]- (4-) in 66 % yield. Protonation of the Cs+4(-) salt with concentrated H2SO4 or CF3COOH in CH2Cl2 afforded a new, highly volatile 2-CB6H8 (4) carborane in 95 % yield, the deprotonation of which with Et3N in CH2Cl2 leads quantitatively to Et3NH+[2-CB6H7](-) (Et3NH+4(-)). Both compounds 4- and 4 can be deboronated through treatment with concentrated hydrochloric acid in CH2Cl2 to yield the carbahexaborane nido-2-CB5H9 (5) in 60 % yield. New compounds 2-, 3, and 4 were structurally characterised by the ab initio/GIAO/MP2/NMR method. The method gave superior results to those carried out using GIAO-HF when relating the calculated 11B NMR chemical shifts to experimental data.     

乳状液膜法提取L—谷氨酸的研究

乳状液膜法提取Ｌ－谷氨酸的研究徐占林（四平师范学院化学系四平１３６０００）严忠张河哲（东北师范大学化学系长春１３００２４）关键词Ｌ－谷氨酸乳状液膜载体萃取中图分类号Ｏ６２３．７３６氨基酸作为重要的生化产品，广泛应用于食品、饲料、医药、化工等许多领域，...     

Designing an enzymatic oscillator: bistability and feedback controlled oscillations with glucose oxidase in a continuous flow stirred tank reactor

The reaction of glucose with ferricyanide catalyzed by glucose oxidase from Aspergillus niger gives rise to a wide range of bistability as the flow rate is varied in a continuous flow stirred tank reactor. Oscillations in pH can be obtained by introducing a negative feedback on the autocatalytic production of H+ that drives the bistability. In our experiments, this feedback consists of an inflow of hydroxide ion at a rate that depends on [H+] in the reactor as k0[OH-]0[H+]/(K+[H+]). pH oscillations are found over a broad range of enzyme and ferricyanide concentrations, residence times (k0 (-1)), and feedback parameters. A simple mathematical model quantitatively accounts for the experimentally found oscillations.     

1,2,3-triazolate-bridged tetradecametallic transition metal clusters [M14(L)6O6(OMe)18X6] (M=FeIII, CrIII and VIII/IV) and related compounds: ground-state spins ranging from S=0 to S=25 and spin-enhanced magnetocaloric effect

We report the synthesis, by solvothermal methods, of the tetradecametallic cluster complexes [M14(L)6O6(OMe)18Cl6] (M=FeIII, CrIII) and [V14(L)6O6(OMe)18Cl6-xOx] (L=anion of 1,2,3-triazole or derivative). Crystal structure data are reported for the {M14} complexes [Fe14(C2H2N3)6O6(OMe)18Cl6], [Cr14(bta)6O6(OMe)18Cl6] (btaH=benzotriazole), [V14O6(Me2bta)6(OMe)18Cl6-xOx] [Me2btaH=5,6-Me2-benzotriazole; eight metal sites are VIII, the remainder are disordered between {VIII-Cl}2+ and {VIV=O}2+] and for the distorted [FeIII14O9(OH)(OMe)8(bta)7(MeOH)5(H2O)Cl8] structure that results from non-solvothermal synthetic methods, highlighting the importance of temperature regime in cluster synthesis. Magnetic studies reveal the {Fe14} complexes to have ground state electronic spins of S相似文献   

Kinetics and mechanism of bromate-bromide reaction catalyzed by acetate

The initial rate of the bromate-bromide reaction, BrO3- + 5Br- + 6H+ --> 3Br2 + 3H2O, has been measured at constant ionic strength, I = 3.0 mol L(-1), and at several initial concentrations of acetate, bromate, bromide, and perchloric acid. The reaction was followed at the Br2/Br3- isosbestic point (lambda = 446 nm) by the stopped-flow technique. A very complex behavior was found such that the results could be fitted only by a six term rate law, nu = k1[BrO3-][Br-][H+]2 + k2[BrO3-][Br-]2[H+]2 + k3[BrO3-][H+]2[acetate]2 + k4[BrO3-][Br-]2[H+]2[acetate] + k5[BrO3-][Br-][H+]3[acetate]2 + k6[BrO3-][Br-][H+]2[acetate], where k1 = 4.12 L3 mol(-3) s(-1), k2 = 0.810 L4 mol(-4) s(-1), k3 = 2.80 x 10(3) L4 mol(-4) s(-1), k4 = 278 L5 mol(-5) s(-1), k5 = 5.45 x 10(7) L6 mol(-6) s(-1), and k6 = 850 L4 mol(-4) s(-1). A mechanism, based on elementary steps, is proposed to explain each term of the rate law. This mechanism considers that when acetate binds to bromate it facilitates its second protonation.     

H_3PMo_(12-n)WnO_(40)·xH_2O的电子光谱与电化学性质研究

系统地考察了H3PMo12 -nWnO4 0 ·xH2 O系列酸在不同溶剂中的电子光谱行为 ,结果表明 ,Mo Ob ,c Mo键在稀水溶液中断裂 ,而在乙醇溶液中能够稳定存在 ;W Ob ,c W键在极稀的水溶液中也能够稳定存在 ;在有机溶剂中所有酸的特征吸收峰均发生红移。电化学性质的研究表明 ,随着分子中钨原子取代数的增多 ,酸的氧化性降低 ,最高还原峰电位和分子中钨原子取代数之间存在一近似线性关系。     

An equilibrium analysis of the aqueous H+-MoO4(2-)-(HP)O(3)2- and H+-MoO4(2-)-(HP)O(3)2--HPO4(2-) systems

The speciation in the phosphitomolybdate system, H+-MoO4(2-)-(HP)O(3)2-, has been determined from combined potentiometric and 31P NMR measurements in 0.600 M Na(Cl) medium at 298(1) K. Potentiometric titration data were collected in the ranges 2.5<-log[H+]<6.2, 40.0相似文献   

Synergistic extraction of cobalt (II) by beta hydroxy naphthaldoxime and neutral donors

Liquid - liquid extraction of Cobalt (II) from aqueous hydrochloric acid medium by the use of oxime derivative of beta-hydroxy naphthaldehyde in o-xylene medium is being reported. The ligand was synthesized and characterized in our laboratory. The typical pH range of extraction of Co (II) by the ligand - donor combination was seen to be between 8 - 9. The effect of different donors like dimethyl sulphoxide (DMSO), trioctyl phosphine oxide (TOPO) and bis(2-ethylhexyl) phosphonate and the effect of various diluents on the extraction of Co(II) by the present method were studied in detail. The binary adduct formation constant (log kex) in the organic phase was found to be 3.182. The overall equilibrium constant (log K) for the ternary species [Co(A)(DMSO)(Cl)], [Co(A)(TOPO)(Cl)] and [Co(A)(phosphonate)(Cl)] were estimated to be 6.42, 6.22 and 6.25 respectively. The trend in equilibrium constants were in accordance with their basic character, i.e., (DMSO > or = TOPO approximately/= phosphonate). The results were extrapolated in the determination of Cobalt in pharmaceutical drugs and cobalt bearing ore samples.