Bismuth Film Electrode for Analysis of Tetracycline in Flow Injection System

A bismuth film was prepared on glassy carbon electrode (GCE) and used in a flow injection amperometric system to analyze tetracycline. Bismuth film electrode (BiFE) preparation and flow injection amperometric parameters were optimized. System performances of BiFE were compared to GCE. BiFE was validated with three different lots of real sample, 250 mg tetracycline capsules, the results showed good agreement, i.e., between 240 and 260 mg per capsule. Good relative recoveries were also obtained in the range of 86–106%.     

流动注射分析

本文是《分析试验室》杂志“流动注射分析”专题定期评述的第五篇，评述了国内学者自１９９５年１月至１９９６年１２月期间在国内外发表的有关流动注射分析的论文。内容包括：会议、基础研究与一般性问题、仪器与装置、分光光度检测、原子光谱检测、电化学检测、化学发光及荧光检测等。共引用参考文献２５０篇。     

Barrel Plating Rhodium Electrode: Application to Flow Injection Analysis of Hydrazine

We introduce here the application of barrel plating technology for mass production of disposable‐type electrodes. Easy for mass production, barrel plating rhodium electrode (Rh‐BPE) is for the first time demonstrated for analytical application. Hydrazine was chosen as a model analyte to elucidate the electrocatalytic and analytical ability of the Rh‐BPE system in pH 7 phosphate buffer solution. Flow injection analysis (FIA) of hydrazine showed a linear calibration range of 25–1000 ppb with a slope and a regression coefficient of 5 nA/ppb and 0.9946, respectively. Twenty‐two replicate injections of 25 ppb hydrazine showed a relative standard deviation of 3.17% indicating a detection limit (S/N=3) of 2.5 ppb. The system can be continuously operated for 1 day without any alteration in the FIA signals and is tolerable to the interference of oxalic acid, gelatine, Triton X‐100, and albumin for even up to 100 times excess in concentration with respect to 400 ppb hydrazine. Since the fabrication cost of the electrode is cheap, it is thus disposable in nature. Furthermore, barrel plating technique can be extendable to other transition metals for application in many fields of research interest.     

Electrochemical Preparation of a Nanostructured Poly(amino napthalene sulfonic acid) Electrode Using CTAB as a Soft Template and Its Electrocatalytic Application for the Reduction of Iodate

A nanostructured poly(5‐amino‐2‐naphthalene sulfonic acid) (nanostructured PANS) electrode has been prepared using cetyltrimethyl ammonium bromide (CTAB) as a soft template by potentiodynamic method. The effect of CTAB at various concentrations was analyzed during electrochemical synthesis of the PANS electrode. As the concentration was near to cmc of CTAB, well growth and nanostructured PANS electrode was obtained. The formation mechanism and the reason for the increase of the peak current of the nanostructured PANS electrode are discussed. The surface morphology of PANS electrode was investigated using scanning electron microscopy (SEM) and a nanoribbon like structured PANS polymer was obtained near cmc of CTAB. The electrochemical properties of nanostructured PANS electrode were studied. The catalytic utility of nanostructured PANS electrode was investigated and it exhibited electrocatalytic activity for the reduction of iodate with a low potential. The amperometric detection of iodate was tested at nanostructured PANS electrode. Linear range and detection limit were found to be 0.1 to 0.4 µM and 0.1 µM, respectively. The present work involves a simple, and one‐step approach to fabricate a nanostructured PANS film with unique electrochemical properties, which can have great potential in various applications such as sensors, and energy source systems.     

Electrocatalytic Reduction and Flow Injection Analysis of Organic Peroxides at Polymeric Tetra-Amino Iron Phthalocyanine Modified Electrode

Abstract

It has been demonstrated that tetra-amino iron phthalocyanine can be polymerized onto a glassy carbon electrode by electrooxidation of the monomer in solution. Organic peroxides can be catalytically reduced at such polymeric film modified electrode. While on a bare glassy carbon electrode, none of the peroxides can be reduced within the potential range studied. When used in flow injection analysis, the modified electrode permits the detection of these compounds by reduction mechanism at higher potentials without the interference from oxygen. The response is stable and has a wide dynamic range.     

流动注射分析

本文是《分析试验室》定期评述专号中“流动注射分析”课题的第二篇评述文章。它评述了1988年10月至1990年10月流动注射分析在我国的进展及国际上发展的新动向。内容包括:基础研究、实验装置与仪器、分光光度分析、原子光谱、电化学检测和化学发光分析、梯度技术与计算机方法等。     

Fabrication of a Nitrate Selective Electrode for Determination of Nitrate in Fertilizers by Using Flow Injection Analysis System

A nitrate ion selective electrode (nitrate-ISE) based on pyrrole modification on a common pencil lead was proposed. The lab-made nitrate-ISE was easily constructed by pyrrole polymerization with nitrate ion as the dopant using cyclic voltammetry. The fabricated nitrate-ISE was then coupled with flow injection analysis (FIA) for an automatic system. The flow potentiometry provided working range of 1x10^-4 to 4x10^-3 mol L^-1 of nitrate and allowed sample throughput up to 50 samples h^-1. Linear regression analysis showed good agreement (r²=0.9961) with Nernstian response. This system was applied to determine nitrate-nitrogen (nitrate-N) in fertilizer samples.     

Decolorization Reactions Between Chromium (VI) and Three Colour Reagents. Determination of Chromium (VI) by Flow Injection Analysis

Abstract

Chromium (VI) can oxidize and decolor three colour reagents, i.e. 1,8-dihydroxy-2-(4′-chloro-2′-phosphonophenylazo)-7-(6″.8″-disulfonaphthylazo)-3,6-disulfonaphthalene (RI): 1,8-dihydroxy-2-(4′-chloro-2′-phosphonophenylazo)-7-(4″-sulfonamidephenylazo)-3,6-disulfonaphthalene (RII): and 1,8-dihydroxy-2-(4′-chloro-2′-phosphonophenylazo)-7-(p-hippuric acid azo)-3,6-disulfonaphthalene (RIII). Loss of absorbance of three colour reagents at maximum absorption wavelengths is proportional to the concentration of chromium (VI) in solution. We have made use of the decolorization reactions between chromium (VI) and three colour reagents to determine chromium in steel by flow injection analysis, and relative error in sample determination is less than 5.0%. Response is linear from 0.84 to 6.72 μg/mL and optimum measuring acidity is 1.3–1.7 mol/L H₂SO₄ in three systems. The effect of interference ions on determination has been studied.     

流动注射分析用新型钆离子电极

功能高分子为活性材料,加热压片,制成新型钆电极。其性能较PVC式钆离子选择电极为优。取钆电极膜片制成流通式钆电极,与流动注射仪联用,测得电极斜率59mV,与静态响应相似。每次进样500μl,测定频率每小时60～100次。操作简单,重现性好。     

壁喷电池在流动注射阳极溶出伏安法中的应用

在流动注射阳极溶出伏安法中应用壁喷电池,探讨了非稳定态电积过程的溶出峰电流理论方程,预言了峰电流正比于R~(3/4)(R为工作电极半径),并对有关参数进行了实验验证。对5×10~(-7)mol/L Cd(Ⅱ)连续测定40次,表明相对标准偏差为0.94％。     

New Determination Scheme of p‐Aminophenol by MnO2 Modified Electrode Coupled with Flow Injection Analysis

New determination scheme of p‐aminophenol by using MnO₂ as a preoxidant is demonstrated in this work. In the flow injection system, the p‐aminophenol is oxidized to quinoneimine by MnO₂ at up‐stream, which can be detected at a suitable reductive potential. After optimization, the linear range of PAP is started from 1 μM to 30 μM (R²=0.999), the estimated detection limit (S/N=3) is 0.28 μM. Two real samples are studied and excellent recoveries are achieved by using standard addition method.     

微酶电极的研制及在流动注射分析中的应用

利用铂化电极的大表面吸附葡萄糖氧化酶（简称ＧＯＤ）构建了一种具有良好操作性能的微酶电极，在０～１０ｍｍｏｌ／Ｌ葡萄糖浓度具有很好线性，相关系数γ＝０．９９８，响应时间短（＜２０ｓ），精度高。利用该电极组成三电极流动注射分析系统，这种系统同样有较好的线性范围，分析频率达４５ｈ＾－１，使用寿命在一周以上。     

Design of the Fluoride Ion-Selective Electrode as Tubular Detector for Flow Injection Analysis

ABSTRACT

Design of the fluoride ion-selective electrode (FISE) as the tubular detector used in the flow injection analysis (FIA) has been described. Among other things, this design makes it possible to use various internal contacts. The effect of pH on peak height and detection limit in the pH range from 2.8 to 8.0 has been examined. The effect of flow rate and sample injection volume on peak height and range of linear response has also been examined. The flow rates range from 0.56 mL/min to 4.05 mL/min, while the injection volumes are 100 and 200 μL. The optimum conditions are carrier solution (0.1 M KNO₃ buffer pH 4 and 10^-6 M NaF), flow rate 1.54 mL/min and sample injection volume 100 μL.

Applicability of the FISE as the tubular detector in determination of Fe(III)-ions and AI(III)-ions by flow infection analysis has been examined at pH values of 2.8 and 3.4.     

纳米PbO2修饰电极安培检测器流动注射法快速测定化学需氧量

采用以纳米PbO₂修饰电极为工作电极的安培检测器,用流动注射法快速检测水体中的化学需氧量(COD).根据纳米PbO₂修饰电极催化氧化电流的大小测定样品的COD值,在50-1 200 mg/L COD的范围内,电流响应与标准水样中的COD_Cr值呈线性关系,检出限为20 mg/L.该法不需对水样进行预处理,不使用有毒试剂,无二次污染,具有快速、简便、进样量少及工作电极使用寿命长等优点,与COD_Cr国家标准分析法对比具有较好的相关性.     

流动注射掺杂普鲁士蓝碳糊电极测定过氧化氢

在化学法制得普鲁士蓝(PB)粉末的基础上,用固体石蜡作粘合剂,将PB粉末和石墨粉按一定比例充分混合,制得掺杂PB的碳糊电极(PBCPE)。研究了该修饰电极的制备,电化学性质及对H2O2的电催化作用。该修饰电极在0.5mol/L的KCl底液中进行循环伏安实验,于0.2V(vs.SCE)附近出现一对氧化还原峰,扫速为30mV/s时,峰电位差67mV,重现性良好。采用流动注射进样,基于PBCPE电极成功实现了恒电位快速检测医用消毒水中H2O2的浓度。最佳检测电位为-0.3V,进样频率为120次/小时。响应电流与H2O2的浓度在0.08～3.2mmol/L范围内呈良好的线性关系,线性相关系数为0.9994,检出限为2.4×10-6mol/L(S/N=3)。