纳米多孔双金属氧化物在镍钛合金纤维上的原位生长及其对多环芳烃的选择性固相微萃取

采用阳极氧化法在镍钛合金(NiTi)纤维上原位生长了双金属氧化物纳米孔(NiTiONPs)涂层,通过扫描电镜(SEM)和能谱(EDS)考察了电解质组成和电压对形貌的影响。将NiTiONPs涂层的NiTi纤维与高效液相色谱-紫外检测器联用,研究了4种典型芳香分析物的萃取性能。结果表明,富含TiO2的NiTiONPs涂层对多环芳烃(PAHs)具有良好的萃取效率,尤其对苯并[a]芘的萃取选择性优于市售聚二甲基硅氧烷纤维和聚丙烯酸酯纤维。在优化条件下,PAHs的线性范围为0.05~200μg/L,相关系数均大于0.999,检出限为0.012~0.134μg/L。对单支纤维日内和日间分析的相对标准偏差(RSDs)分别为4.0%~5.5%和6.0%~6.8%,使用分批组装的5支纤维分析的RSDs为6.4%~7.6%。实际水样分析的加标回收率为84.5%~111.5%。所制备NiTi纤维至少可重复使用250次以上,重现性好。     

Determination of chloride by stripping chronopotentiometry with silver-film electrode

The experimental parameters of cathodic stripping chronopotentiometry of chloride at a silver-film electrode are investigated and optimized. The chloride preconcentration is achieved in the form of silver chloride by a controlled potential oxidation of the working electrode under vigorous stirring. Cathodic stripping of the deposit is obtained by the constant current, under the condition of diffusive mass transfer. Deaeration of the solution is not necessary. A detection limit of 35 μ dm⁻³ (10⁻⁶ mol dm⁻³) is obtained at a deposition time of 180 s, with a reproducibility of 6.7 % (expressed as relative standard deviation, RSD).     

PVA固定化脲酶电极的制作及电极特性的研究

利用PVA低温下的物理交联固定酶,制成酶电极并在不同尿素浓度、pH值、温度等条件下进一步研究这种酶电极的响应特性.     

电极条件对硫酸介质中电解还原提纯镱过程的影响

研究了以钌铱钛合金网和汞分别为阳、阴电极, 在无气氛保护条件下, 采用电解还原方法从铥、镱、镥硫酸盐溶液中分离提纯镱的过程. 讨论了在8 V恒电压时的电极间距、位置, 以及阴、阳极表面积对电解过程中的电流、还原率影响. 优化了电解还原过程, YbSO4产品的纯度稳定达到99.5%以上, 一次收率可达80%;提镱后母液中的铥和镥被富集4倍以上, 其中Lu含量高于50%, 十分有利于后续铥/镥分离.     

Characteristic behavior of macro-, semimicro- and microelectrodes in voltammetric and chronoamperometric measurements

The advantages of microelectrodes such as the improvement of signal-to-noise ratio, the ability to perform electrochemical measurements in high resistive solutions and small RC-time constants give the possibility of an extended use for voltammetric and chronoamperometric techniques in analytical chemistry. In this comparative study, the microelectrode properties of three selected electrodes were examined. The characterization of a RAM-microarray electrode, an epoxy-impregnated carbon electrode and a conventional glassy carbon macroelectrode was performed by cyclic voltammetry at different scan rates, by DP-voltammetric measurements using different concentrations of supporting electrolyte and by transient measurements. It could be shown, that in comparison to the microarray electrode and to the glassy carbon macroelectrode, respectively, the results obtained by using the epoxy-impregnated carbon electrode are caused by its semimicroelectrode character.     

聚乙烯醇缩丁醛膜涂丝酶电极构造方法的研究

本文以三月桂胺为中性载体制成聚乙烯醇缩丁醛膜涂丝pH电极,再以该pH电极为换能器,采用三种共价交联固定化酶方法制成涂丝乙酰胆碱酯酶电极。该酶电极能用于测定0.1～10mmol/L浓度范围内的乙酰胆碱,响应时间在3～6min之内,寿命可达两个多月。     

An Inexpensive Biosensor for Uric Acid Determination in Human Serum by Flow‐Injection Analysis

An inexpensive and easy to construct miniaturized biosensor is described for the determination of uric acid in biological fluids. The amperometric biosensor was prepared by using a carbon paste electrode prepared with uricase from Arthrobacter globiforms and tetracyanoquinodimethane as electron transfer mediator. When incorporated into a flow‐injection system it was enabled to perform 50 measurements/h of uric acid in the analytical range of 1–100 μmol dm^?3 with a relative standard deviation of 0.20% (n=14). The system was applied to human serum samples analysis providing good data correlation with those obtained by the reference spectrophotometric method. A linear relationship AM (μmol dm^?3)=1.02 (±0.05) SP (μmol dm^?3) ?0.12 (±0.13) was obtained evidencing the absence of significant error. The constructed biosensor was successfully used for at least four months (250 assays) with only a 13% of decrease in the enzymatic activity.     

聚酰胺修饰碳糊电极测定槲皮素的研究

用聚酰胺修饰碳糊电极在ｐＨ３６０的Ｂｒｉｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲溶液中，将槲皮素开路富集一定时间后，从０４５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）向阴极化扫描至－０５５Ｖ获得Ｉ－Ｅ曲线。槲皮素的峰电位为０１８Ｖ。峰电流与槲皮素浓度在１０～４００μｍｏｌ／Ｌ范围内呈良好的线性关系。所拟定方法用于芦丁水解产物测定，结果满意。     

Perfluorinated anion-exchange polymer mercury film electrode for anodic stripping voltammetric determination of zinc(II): effect of model organic compounds

The determination of zinc ion (1-60 ng ml⁻¹) by anodic square-wave stripping voltammetry on an anion-exchange perfluorinated polymer Tosflex mercury film electrodes (TMFE) was evaluated. The detection limit was 0.1 ng ml⁻¹ Zn(II). The effect of various organic compounds (gelatin, albumin, starch, camphor, humic acid, Triton X-100, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB)) is explored. The results indicate that due to the size-exclusion and ion-exchange properties of Tosflex film, the TMFE is considerably more resistant to organic interference than the bare mercury film electrode.