普鲁士蓝修饰电极结合硅溶胶-凝胶技术制备高灵敏葡萄糖传感器

基于普鲁士蓝修饰玻碳电极结合二氧化硅溶胶 凝胶固定化酶技术构造具有“三明治”式结构的酶电极。考察了酶电极对葡萄糖的电化学响应以及操作条件。结果表明 :所制备的传感器在pH 6 .5 ,电位为- 0 .0 5V条件下对葡萄糖在 0～ 5mmol/L呈线性响应 ,响应时间为 12s ,检出限为 0 .0 2mmol/L ,灵敏度高达1 182 μA/ (mmol·L-1)。传感器的稳定性好 ,4 5d其响应值仍保持 90 %。     

共沉淀法合成Zn掺杂Co2-Y平面六角铁氧体粉的热力学分析

通过对 Me(Ba2+,Zn2+,Co2+,Fe3+)-CO32--NH3H2O体系进行热力学分析,得到不同的总碳浓度(cc)和总氮浓度(cN)时各金属离子总浓度(e,t曲与pH值关系,由此确定4种金属离子共沉淀完全的pH值范围.热力学分析表明:以Na2CO3和NH3·HzO作沉淀剂,用共沉淀法合成Zn掺杂Co2-Y平面六角铁氧体粉时,体系pH值由Ba2+和Zn2+沉淀完全的酸度条件决定,而两者取决于cc和cN的相对关系;当Cc＞1.000 mol·L-1、cN＜0.100 mol·L-1时,控制pH值在8～12范围内,即町确保共沉淀完全.     

阳离子混凝剂PDA对水中苯酚的去除研究

采用强化混凝法去除水中持久性有机污染物苯酚。对自制聚丙烯酰胺进行红外光谱(IR)和电镜扫描(SEM)表征。以苯酚为目标物,自制PDA为混凝剂,对含酚模拟废水进行混凝处理。研究了混凝剂投加量、搅拌强度、静置时间以及pH值对去除效果的影响。红外结果表明产物确为丙烯酰胺与二甲基二烯丙基氯化铵的共聚物(PDA);SEM显示其表面粗糙、多孔,表明其具有良好的吸附架桥能力。当苯酚初始浓度为0.75mg·L~(-1)时,PDA投加量为0.06mg·L~(-1),pH值控制在6~7,270r·min~(-1)快搅2min,50r·min~(-1)慢搅12min,沉降时间为30min时,苯酚去除率可达82.1%。     

2-(2-喹啉偶氮)-5-二甲氨基酚分光光度法测定钒

研究了新试剂2 (2 喹啉偶氮) 5 二甲氨基酚(QADMAP)与钒的显色反应,在pH3.5的柠檬酸 NaOH缓冲介质中,溴化十六烷基三甲基胺(CTMAB)存在下,QADMAP与钒反应生成2∶1稳定络合物,络合物最大吸收波长为580nm,摩尔吸光系数ε=1 12×105L·mol-1·cm-1,钒质量浓度在0～0 6μg mL内符合比尔定律。方法已用于几种合金样品中钒的分析。     

铈(Ⅳ)与DBC-偶氮胂褪色光度法研究

在 0 18～ 1 0 8mol·L- 1H2 SO4 介质中 ,Ce(Ⅳ )对DBC 偶氮胂具有褪色作用 ,该褪色反应表现摩尔吸光系数为ε530nm=1 0 3× 10 4mol- 1·L- 1·cm- 1,Ce(Ⅳ )量在 1 2～ 12 0 μg·mL- 1范围内与有色溶液吸光度减少值呈线性关系 ,遵守比尔定律 ,研究了 36种共存离子的影响。方法已用于测定水样中的痕量铈 ,结果令人满意。本法具有准确度高 ,选择性好 ,操作简便快速的优点。本文提出了褪色反应机制。     

咖啡酸玻碳修饰电极对烟酰胺腺嘌呤二核苷酸的电催化氧化

研究了咖啡酸修饰电极的制备、性质及对NADH的电催化作用。修饰电极在0．1mol/L PBS缓冲溶液中(pH7．0)于0．0～ 050V(vs.Ag／AgCl)电位范围内呈现一对氧化还原峰，式量电位(E^0‘‘)为 0．250V(vs．Ag／AgCl)。E^0‘‘随pH增加而朝负方向移动，pH在5．0～8．0范围内，其线性回归方程为E^0‘‘=0．6233-0．05996pH，R=0．9969。表观电极反应速率常数(Kb)为12．3s^-1。电极反应的电子数为2且有2个质子参与。该修饰电极对NADH的氧化具有很好的电催化作用。NADH浓度在0．1—6．0mmol／L．范围内与峰电流呈现良好的线性关系。文中对电催化过程进行了探讨。     

以新亚甲蓝为介体的过氧化氢传感器的电化学行为研究

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)修饰于玻碳电极表面,制成一种新型的电流型H2O2传感器。探讨了该传感器在0·1mol/L磷酸缓冲溶液(pH=7·0)中的电化学性质。结果表明,NMB作为介体能够有效地在辣根过氧化酶和电极之间传递电子。测得电子转移系数为0·861,表观反应速率常数为1·27s-1。研究了传感器对H2O2的响应及动力学性质,米氏常数为8·27μmol/L,线性响应范围为2·5~100μmol/L。同时研究了pH、缓冲容量及温度等因素对H2O2传感器的影响。     

配合物Mg(OEt)(acac)的电化学合成

在溴化四丁基铵[(Bu4N)Br]的乙醇(EtOH)和乙酰丙酮(acacH)混合溶液中,电流强度0.2A,电解镁片6 h制得乙氧基镁配合物Mg(OEt)(acac).Bu4NBr浓度在40 mmol·L-1～50 mmol·L-1时,电流效率超过90%.在Mg(OEt)(acac)浓度210 mmol·L-1,pH 8.0,于40℃水解12 h的条件下,Mgo干凝胶收率超过87%.Mg(OEt)(acac)和Mg0干凝胶的结构经1H NMR,IR,XRD和拉曼光谱表征.     

去甲肾上腺素电极过程的圆二色谱电化学研究

现场圆二色薄层光谱电化学研究去甲肾上腺素的电化学氧化还原过程 .研究表明去甲肾上腺素 ( pH =7.0磷酸缓冲溶液中 )在玻碳电极上经历了不可逆的电化学氧化 ,且遵从后行化学反应 (EC)机理 ,去甲肾上腺素醌和去甲肾上腺素红的再还原遵从简单电子转移 (E)机理 .由双对数法获得去甲肾上腺素电化学氧化的式电位为E10’=0 .2 0V ,电子转移系数和电子转移数之积为αn =0 .38,标准复相电极反应常数k10 =1 .2× 1 0 -4 cm·s-1.去甲肾上腺素醌和去甲肾上腺素红的电化学还原反应参数分别为E2 0’=0 .2 5V ,αn =0 .37,k2 0 =4.4× 1 0 -5 cm·s-1和E3 0’=- 0 .2 5V ,αn =0 .33,k3 0 =1 .1× 1 0 -4 cm·s-1.     

Characteristic and Mechanism of Cr（VI） Biosorption by Buckwheat Hull from Aqueous Solutions

农业废弃物荞麦皮作为生物吸附剂去除水中Cr（VI）,研究了荞麦皮对Cr（VI）的去除动力学以及溶液pH、吸附剂用量和Cr（VI）初始浓度对去除效率的影响;通过FT-IR,XPS,SEM．EDX对荞麦皮表面组成和结构进行表征,探索荞麦皮去除Cr（VI）的机理．结果显示：荞麦皮对Cr（VI）有很高的去除效率．常温下5．0g·L^-1的荞麦皮在pH=2.0下对100mg·L^-1Cr（V0溶液的去除率可达99．87％．荞麦皮对Cr（VI）的去除率随溶液pH降低而升高,在pH=2.0时达到最大;随吸附剂用量增加而增大;随Cr（VI）初始浓度增加而减小．单位质量荞麦皮对Cr（V1）的去除量随吸附剂用量增加而减小;随Cr（VI）初始浓度增加而增加,最后趋于稳定．在20℃,pH=2．0,吸附用量为5．0g·L^-1时,荞麦皮对Cr（W）的最大去除容量约为36．4mg·g^-1．荞麦皮吸附去除Cr（Vb的过程符合准二级吸附动力学．FT-IR,XPS和SEM-EDX分析结果表明：荞麦皮是一个多孔材料,表面存在羧基、氨基、羟基等活性基团;荞麦皮对Cr（VI）的去除是一个吸附一还原耦合的过程,包括Cr（VI）在荞麦皮表面上的静电吸附,以及此后的固相还原和对还原态的Cr（Ⅲ）再吸附;Cr（Ⅲ）的吸附主要是通过与荞麦皮表面的羧基、氨基的配位,以及与其中的阳离子发生离子交换作用实现的．     

锆-氟-7-碘-8-羟基喹啉-5-磺酸-EDTA-表面活性剂体系的荧光光度研究

在pH5.5～7.0的HAc-NaAc缓冲溶液中,锆与氟、7-碘-8-羟基喹啉-5-磺酸(H_2QSI)、EDTA及十六烷基三甲基溴化铵(CTMAB)形成五元荧光络合物,其组成为Zr(Ⅳ):F:H_2QSI:EDTA:CTMAB=1:2:1:1:4.络合物的最大激发波长(λ_(ex))为365nm,最大发射波长(λ_(em))为 500 nm.由此建立了锆的选择性好、灵敏度高的荧光测定新方法.方法的检测限为 0.8μg/L.测锆的线性范围为 0.0016～1.04 mg/L.应用于合金中锆的测定,结果满意.     

Evaluation of peroxide value of olive oil and antioxidant activity by luminol chemiluminescence

Three procedures are developed and investigated for the simple and fast determination of peroxide value of olive oil by luminol chemiluminescence. The procedure using hemin as catalyst in carbonate alkaline solution allows the determination of hydrogen peroxide within the range 0.014-50 μM. The method can be used for the determination of peroxide value within the range 2.00-30.0 mequiv. O₂/kg oil and results correlate very well (r² = 0.99) with those of the official method. All reagents are aqueous solutions and olive oil is dissolved in acetone:ethanol mixed solution and, hence, the method is using minimal amounts of organic solvents and can be successfully applied to field analysis. Antioxidant activity of five common compounds found in natural products was determined by using luminol CL with Co(II) as EDTA complex as catalyst at pH 9.00.     

Novel UV assay for protein determination and the characterization of copper-protein complexes by mass spectrometry

A very simple, highly selective and sensitive assay of proteins based on the biuret absorption in the ultraviolet region has been developed. The well-known biuret assay is based on the reaction of proteins with copper ions under strong alkaline conditions to form a copper-protein complex. Yet, copper ions may seriously interfere with the determination if the measurement is made in the UV range. In the present approach, proteins mobilize copper ions from insoluble salts at different pH values, and the copper-protein complexes are investigated by UV spectrophotometry and mass spectrometry. Upon using copper phosphate, free copper ions do not interfere with the determination from 540 to 240 nm. Copper absorbance slowly increases from 240 to 190 nm where a blank with the reagents is recommended. A maximum absorbance for the copper-protein complex was found at 226 nm and high pH value. The stoichiometries of the copper-protein complexes measured directly with a mass spectrometer are pH dependent: half of the peptides without any histidine residue chelate just a single Cu²⁺ ion at pH 7.4 but each such peptide mobilizes from 1 to 6 Cu²⁺ ions at pH 10.3. To determine proteins, 1-1.5 ml of 1.8% KOH solution with 0-20 μg ml⁻¹ protein is treated with 25 mg of copper phosphate powder. The mixture is powerfully stirred, centrifuged, and the absorbance of the supernatant is measured at 226 nm in 1 cm quartz cuvettes against a blank of the reagents. The color system obeys Beer's law in the range 0.1-20 μg ml⁻¹ protein at this wavelength. The molar absorptivity value proved to be a characteristic of each protein being analyzed. Therefore, individual proteins should be used to plot calibration curves. This assay proved to be over 100 times more sensitive than the classical biuret procedure. The method is highly selective and the determination is little affected by the presence of other substances. All other important analytical parameters were studied and practical applicability of the method has been verified by the analysis of some biological materials.     

柱前衍生/高效液相色谱法测定果蔬中仲丁胺残留

建立了高效液相色谱(HPLC)测定仲丁胺的分析方法。试样采用全自动凯氏定氮仪蒸馏,蒸馏液经碱中和,以9-氯甲酸芴甲酯(FMOC)为衍生剂在碱性条件下衍生,衍生产物经C18柱分离,紫外检测器(265nm)检测。实验考察了衍生剂浓度、硼酸盐缓冲溶液的p H值、反应温度与时间等因素对衍生反应的影响,结果表明,最优的衍生剂浓度为0.50 g/L,缓冲溶液p H值为8.0,反应温度为室温,反应时间为15 min。在此条件下,仲丁胺在0.001~1.000 mg/L浓度范围内与其响应信号呈良好的线性关系,相关系数为0.999 8,加标回收率为82.4%~95.2%,相对标准偏差为1.3%~6.8%,方法检出限为0.1μg/kg,定量下限为0.5μg/kg。该方法快速、简便、安全、灵敏度高、重现性好,可用于果蔬中仲丁胺残留的测定。     

四氰基醌二甲烷修饰碳糊电极电催化氧化测定抗坏血酸

本用四氰基醌二甲烷作价体，制成ＴＣＮＱ－碳糊电极，研究了该电极的性能。电极对水溶液中的抗坏血酸在较宽的ｐＨ和浓度范围内均有良好的电催化氧化作用，电极的稳定性良好，在ＡＨ２浓度５．０×１０＾－５－５．０×１０－２ｍｏｌ／Ｌ范围内，催化峰电流与ＡＨ２浓度呈线性关系，响应时间小于３０ｓ．     

A kinetic method for the determination of copper(II) by its catalytic effect on the oxidation of 3-methyl-2-benzothiazolinone hydrazone with hydrogen peroxide: a mechanistic study.

A catalytic spectrophotometric method for the determination of traces of copper(II) is proposed. 3-Methyl-2-benzothiazolinone hydrazone (MBTH) is oxidized by hydrogen peroxide to form a yellowish-brown compound. The reaction is accelerated by trace amounts of copper(II), and can be followed by measuring the increase in the absorbance at 390 nm. Since the absorbance at 40 min from the reaction start increases with an increase in the copper(II) concentration, the absorbance value is used as a parameter for copper(II) determination. Under the optimum experimental conditions (8.4 x 10(-3) mol dm(-3) MBTH, 0.7 mol dm(-3) hydrogen peroxide, pH 5.2, 35 degrees C), copper(II) can be determined in the range 0-50 microg dm(-3). The relative standard deviations are 6.9, 3.5, 2.7% for 2, 20 and 40 microg dm(-3), respectively. The detection limit of this method (3sigma) is 0.27 microg dm(-3). It was successfully applied to a determination of copper(II) in river water, tap water and ground-water samples. According to the results of a kinetic study, a mechanism is proposed which leads to the following rate equation: R0(cat) = kK1K2[MBTH][H2O2][Cu(II)]0/{(1 + K2[H2O2])[H+]}.     

液相微萃取-高效液相色谱联用分析化妆品中痕量的雌激素

建立了液相微萃取-高效液相色谱联用(LPME-HPLC)测定爽肤水中痕量的雌三醇、雌二醇、炔雌醇和雌酮的分析方法,研究了萃取溶剂种类、接受相体积、搅拌速度、萃取时间等对萃取效率的影响。结果表明,该方法对4种雌激素的富集倍数可达到247~343倍,方法的线性范围为1~200 μg/L,检出限为0.4~1.0 μg/L,6次平行测定的相对标准偏差为3.6%~7.3%,爽肤水中的加标回收率为101.2%~114.9%。方法简单快速、灵敏度高、环境友好,满足痕量雌激素分析的要求。     

核酸水解产物嘌呤、嘧啶碱基在BDS柱上的分离及测定

 用高效液相色谱法测定了核酸水解的中间产物及最终产物 6种嘌呤、嘧啶碱基 ,探讨了色谱柱、流动相等对其分离的影响 ,确定了最佳色谱条件为 :HypersilBDS C18柱 ,乙腈 0 1mol/LKH2 PO4 (H3 PO4 调节 pH至4 0 5 ) (体积比为 2∶98)作流动相 ,紫外检测器在 2 6 0nm波长下检测。方法的精密度在 3%以内 ,回收率在 82 %～ 114%。方法应用于酵母核酸样品的测定中 ,取得了很好的结果。     

Aluminium determination in environmental samples by graphite furnace atomic absorption spectrometry after solid phase extraction on Amberlite XAD-1180/pyrocatechol violet chelating resin

A chelating resin, pyrocatechol violet (PV) immobilised on an Amberlite XAD-1180 support, was prepared and its use for the atomic absorption spectrometric determination of aluminium was investigated. The XAD-1180-PV resin was characterised by infrared spectrometry and thermal gravimetric analysis. The optimum pH value for quantitative sorption is 8-9, and desorption can be achieved by using 5.0-10.0 ml of 2 M HCl. The effects of diverse ions on the sorption and recovery of aluminium have been studied. The capacity of sorbent was 6.45±0.59 mg g⁻¹ Al XAD-1180-PV. Recoveries for aluminium from water samples were in the range 95-105%. The accuracy of procedure was confirmed by aluminium determination in certified reference materials. The method developed was applied with varying results to the analysis of natural water, haemodialysis fluids and microwave digested red wine samples from Tokat City.     

浊点萃取-高效液相色谱法测定铜、钴

讨论了以5-Br-PADAP为衍生试剂,用Triton X-114非离子表面活性剂浊点萃取富集铜（Ⅱ）、钴（Ⅱ）的条件,并于ODS柱上,用内含2．0mmol·L^-1十六烷基三甲基溴化铵（CTMAB）和5mmol·L^-1 pH5．0 HAc—NaAc缓冲溶液的V（甲醇）＋V（乙腈）＋V（水）=67＋8＋25混合液作流动相．检测波长为568nm,流量为0．8mL·min^-1。,发展了浊点萃取-高效液相色谱法测定铜、钴的新方法。在选定条件下,大多数离子不干扰测定,方法灵敏度高,经浊点萃取后可提高测定响应值7—8倍,对铜、钴的检测限分别为0．5μg·L^-1,0．8μg·L^-1。方法可用于水样中钴（Ⅱ）、铜（Ⅱ）的测定,结果令人满意。