多壁碳纳米管-分子印迹传感器测定盐酸克伦特罗

结合碳纳米材料和分子印迹技术,建立了以K3[Fe(CN)6]为探针测定盐酸克伦特罗的方法。以邻苯二胺为功能单体,盐酸克伦特罗为模板,采用电化学聚合法在多壁碳纳米管修饰电极表面制备了分子印迹薄膜。用乙腈水溶液可快速去除模板,得到多壁碳纳米管-分子印迹传感器。用循环伏安法、交流阻抗法和石英晶体微天平技术对印迹膜进行了表征,膜厚为12.3 nm。K3[Fe(CN)6]的相对峰电流与盐酸克伦特罗的浓度在4.0×10-8～6.6×10-6 mol/L范围内呈线性关系,检测限为8.1×10-9 mol/L。选择性实验表明传感器对结构类似物具有较强的抗干扰能力。此传感器可用于猪肉中盐酸克伦特罗的测定,加标回收率为101.3%～107.9%。     

己烯雌酚分子印迹传感器的制备及其性能研究

应用分子印迹技术,以邻苯二胺为功能单体、己烯雌酚为模板,采用循环伏安法在玻碳电极表面合成了性能稳定的己烯雌酚分子印迹聚合膜,并用50%(V/V)乙醇溶液迅速去除模板,得到对己烯雌酚响应的分子印迹电化学传感器。研究了此分子印迹传感器的分析性能,建立了以K3Fe(CN)6为电子传递媒介的间接分析法。在1.0×10-7～5.1×10-6mol/L范围内,己烯雌酚的浓度与K3Fe(CN)6的相对峰电流变化呈线性关系。选择性实验表明,此传感器对结构相似的分子有较强的抗干扰能力。     

硫酸特布他林分子印迹电极的制备与性能研究

采用分子印迹技术,以邻苯二胺为功能单体,在玻碳电极表面电聚合成聚邻苯二胺分子印迹敏感膜。K3[Fe(CN)6]作为探针分子,通过循环伏安法、差分脉冲法对该电极进行考察。结果表明:电极对硫酸特布他林具有较好的灵敏度与选择性,线性范围为1.52×10-8~1.05×10-6mol/L,检出限(S/N=3)为1.2×10-8mol/L,电极具有良好的重现性与稳定性。将电极用于实际样品的分析,方法回收率为98.4%~107.9%。     

尼泊金乙酯分子印迹膜电化学传感器的制备

以邻苯二胺为功能单体,尼泊金乙酯为模板分子,通过电化学聚合在玻碳电极表面制备了尼泊金乙酯分子印迹膜,采用循环伏安法及方波伏安法,以K3[Fe(CN)6]为电活性探针,建立了间接测定尼泊金乙酯的分析方法。实验结果表明,制备的分子印迹膜电化学传感器对尼泊金乙酯具有较高的选择性和灵敏度,测定尼泊金乙脂的线性范围为2.5×10-6~1.0×10-5 mol/L,检出限为8.61×10-8 mol/L。     

基于分子印迹电聚合膜的褪黑素传感器的研究

在弱酸条件下,以邻苯二胺为功能单体,褪黑素为模板,以电化学聚合物法在铂电极表面合成了性能稳定的褪黑素分子印迹聚合物膜.采用循环伏安法(CV)和差分脉冲法(DPV)对分子印迹传感器的识别性能进行了研究.结果表明:此传感器对褪黑素具有快的响应、良好的选择性和高的灵敏度.以K3Fe(CN)6为电子传递媒介,建立了一种差分脉冲伏安法(DPV)间接检测褪黑素的分析方法.在1×10-10～1×10-8 moL/L范围内,褪黑素的浓度与K3Fe(CN)6的相对峰电流变化呈良好的线性关系;检出限为1×10-11 mol/L(S/N=3).将此传感器应用于复合褪黑素及尿样中褪黑素含量的测定,加标平均回收率大于94％.     

聚吡咯/亚铁氰化钾/碳纳米管修饰电极检测亚硝酸根

采用循环伏安法在滴涂碳纳米管的电极表面制备了聚吡咯/K4Fe(CN)6复合膜,研究了该电极的电化学性质及对NO2-的电催化还原。结果表明,固定于聚吡咯膜中的K4Fe(CN)6作为电子递质与碳纳米管和聚吡咯对NO2-电还原具有协同催化作用,安培法检测NO2-的线性范围为1.5×10-6～1.8×10-3mol/L,检出限为3.0×10-7mol/L,该法已用模拟水样中NO-的测定。     

扑热息痛分子印迹膜电化学传感器的制备

以邻苯二胺为功能单体,扑热息痛为模板,采用循环伏安法在玻碳电极表面电聚合形成邻苯二胺电聚合膜,经无水乙醇将模板分子洗脱,制得扑热息痛分子印迹膜电极.通过方波伏安法研究此印迹传感器的分析性能,建立了以K3[Fe(CN)6]为活性电子探针的间接分析法.实验表明,该传感器具有高选择性和灵敏度.在2.0×10-6 ～8.0×1...     

水胺硫磷分子印迹传感器的制备与应用

在磷酸盐缓冲溶液(PBS)中,以邻苯二胺(o-PD)和没食子酸(GA)为功能单体,水胺硫磷(ICP)为模板分子,采用电位循环扫描法在玻碳电极(GCE)表面进行电聚合,形成绝缘性的分子印迹膜,通过电化学阻抗谱(EIS)和循环伏安法(CV)对分子印迹膜进行表征.在最佳实验条件下,以铁氰化钾[ K3Fe(CN)6]为探针,用差分脉冲伏安法( DPV)对ICP进行定量分析.该传感器在2.00×10 -7～2.00×10-4 mol/L范围内,传感器的响应信号与ICP的浓度呈良好的线性关系,检测限为6.06×10-s mol/L( S/N=3).将其用于蔬果等实际样品中ICP的测定,回收率为95.6％～104.0％.     

碳纳米管修饰电极分子印迹传感器的制备及其对氧乐果的测定

以氧乐果为模板分子,邻苯二胺为功能单体,在碳纳米管修饰的玻碳电极表面通过电聚合方法制成氧乐果分子印迹聚合物膜,用无水乙醇洗脱后制备出对氧乐果有特异响应的电化学传感器。通过循环伏安法和电化学阻抗法对分子印迹传感器的电化学性能进行表征。以K_3Fe(CN)_6为探针,采用差分脉冲伏安法研究了该分子印迹传感器的分析性能,建立了氧乐果的间接测定方法。结果表明,K_3Fe(CN)_6的相对峰电流与氧乐果浓度在1.0×10~(-7)~2.0×10~(-6)mol/L范围内呈良好的线性关系,检出限为3.6×10~(-8)mol/L。     

没食子酸分子印迹聚合物电化学传感器的制备及研究

利用分子印迹技术,以没食子酸为模板分子,甲基丙烯酸为功能单体,采用自由基热聚合的方式制备了分子印迹聚合物,并用于电极的修饰,成功研制了没食子酸分子印迹电化学传感器。以K3[Fe(CN)6]做探针,通过循环伏安法及方波伏安法,考察了该传感器对没食子酸的响应特性,建立了没食子酸的间接电化学分析方法。结果表明,该方法具有较高的选择性和重现性,没食子酸在4.69×10-6~2.14×10-5 mol/L浓度范围内与其氧化峰电流差△Ip呈良好的线性关系,检出限为6.41×10-7 mol/L。将该传感器用于六味地黄丸中没食子酸含量的测定,回收率范围为95.1%~104.8%。     

Utilisation of polypyrrole modified electrode for the determination of pesticides

Cyclic voltammetric studies of isoproturon and carbendazim using polypyrrole modified glassy carbon electrode were carried out. The electrode and reaction conditions, which yielded maximum current signal, were selected for the development of stripping voltammetric procedure for the determination of the pesticides. The oxidation peak around 1.3?V obtained for isoproturon and carbendazim while employing polypyrrole modified electrode showed maximum current response. This peak was chosen for stripping analysis using square wave mode. The experimental parameters were optimized and the calibration plot was obtained. The LOD was 0.5?ng?mL^?1 for isoproturon and 5?ng?mL^?1 for carbendazim. The relative standard deviation for 5 identical measurements was 2.81% and 3.33% for isoproturon and carbendazim respectively. The applicability of the method was verified by determining the pesticides in spiked soil and water samples.     

A membrane-based immunosensor for the analysis of the herbicide isoproturon

A membrane based heterogeneous competitive enzyme-linked immunosorbent assay (ELISA) was used in this work to develop an immunosensor for the detection of a common herbicide, isoproturon. A screen-printed carbon working electrode with carbon counter and silver–silver chloride pseudo-reference electrode was utilized incorporating a membrane fixed into intimate contact with the working electrode to facilitate signal transduction. The membrane containing an immobilized isoproturon–ovalbumin conjugate was laminated onto the carbon working electrode and horseradish peroxidase (HRP) labeled polyclonal antibody was then applied for the competitive assay. Two different amperometric systems, hydroquinone and o-phenylenediamine (OPD) mediation reduction were utilised and the properties of the resultant sensors were compared. A flow injection apparatus was also developed utilising the immunosensor. Limits of detection for isoproturon (LLD₉₀) were found to be as low as 0.84 ng mL⁻¹. The senor was also validated using spiked extracted soil samples and also isoproturon contaminated samples.     

有机农药异丙隆的级联生物降解体系的构建

构建了一个酶促氧化结合活性淤泥处理的级联生物降解有机农药异丙隆的体系.首先,建立了氯过氧化物酶（CPO）催化H₂O₂氧化降解异丙隆的酶处理体系.在最佳反应条件下,异丙隆的降解率可在10 min内达到100%.反应在室温下进行,pH=3.0,所需H₂O₂浓度为0.2 mmol/L,酶用量极少,仅7 nmol/L.降解体系高效、温和、绿色,无二次污染,极具应用潜力.CPO酶促氧化降解异丙隆的产物用HPLC-MS测定,并进一步根据主要产物推测了降解的途径.结果表明,异丙隆经CPO催化H₂O₂氧化处理后,被分解成较小的4-异丙基苯胺和4-乙基苯胺苄基正离子碎片分子.如果将CPO-H₂O₂酶促氧化作为一种前处理手段,后续与活性淤泥微生物降解过程结合,通过这种二级处理方法可实现含异丙隆污水的化学需氧量（COD）的有效去除,达到含异丙隆污水深度治理的目的.进一步以绿藻Chlorella pyrenoidosa的生长抑制率为评价指标对异丙隆酶催化氧化降解的产物进行了毒性评估,结果表明,随着底物降解率的逐渐增大,降解产物对绿藻的生长抑制率逐渐减小,说明经酶法降解后得到的产物与异丙隆相比毒性降低.     

Spectrophotometric determination of isoproturon using p-aminoacetophenone and its application in environmental and biological samples

A simple and sensitive method for the determination of isoproturon, a widely used herbicide is described here which is based on alkaline hydrolysis of isoproturon to its corresponding primary amine followed by diazotization and coupling with p-aminoacetophenone in alkaline medium. The absorption maxima of the coloured compound formed is measured at 525 nm. Beer's law is obeyed over the concentration range of 0.5-5.0 mug in a final solution volume of 25 ml (0.02-0.2 ppm). The molar absorptivity and Sandell's sensitivity were found to be 8.6x10(5) l mol(-1) cm(-1) and 0.0002 mug cm(-2), respectively. The method has been satisfactorily applied to the determination of isoproturon in environmental and biological samples.     

Electroanalysis of some common pesticides using conducting polymer/multiwalled carbon nanotubes modified glassy carbon electrode

The cyclic voltammetric behaviour of three common pesticides such as isoproturon (ISO), voltage (VOL) and dicofol (DCF) was investigated at glassy carbon electrode (GCE), multiwalled carbon nanotubes modified GCE (MWCNTs/GCE), polyaniline (PANI) and polypyrrole (PPY) deposited MWCNT/GCE. The modified electrode film was characterized by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The electroactive behaviour of the pesticides was realized from the cyclic voltammetric studies. The differential pulse voltammetric principle was used to analyze the above-mentioned pesticides using MWCNT/GCE, PANI/MWCNT/GCE and PPY/MWCNT/GCE. Effects of accumulation potential, accumulation time, Initial scan potential, amplitude and pulse width were examined for the optimization of stripping conditions. The PANI/MWCNT/GCE performed well among the three electrode systems and the determination range obtained was 0.01-100 mgL(-1) for ISO, VOL and DCF respectively. The limit of detection (LOD) was 0.1 microgL(-1) for ISO, 0.01 microgL(-1) for VOL and 0.05 microgL(-1) for DCF on PANI/MWCNT/GCE modified system. It is significant to note that the PANI/MWCNT/GCE modified system results in the lowest LOD in comparison with the earlier reports. Suitability of this method for the trace determination of pesticide in spiked samples was also realized.     

基于三聚氰胺膜电催化与酶催化放大的分子印迹电化学传感器测定绿麦隆

以三聚氰胺(MA)作为功能单体, 制备了一种检测环境中农药残留绿麦隆(CH)的分子印迹膜电化学传感器. 基于CH与辣根过氧化物酶(HRP)标记绿麦隆(HRP-CH)的竞争反应实现对CH的检测. 利用聚三聚氰胺膜(PMA)和HRP对过氧化氢的催化效应产生的双放大效应有效地提高传感器检测的灵敏度. 采用计时电流法测量, CH浓度与峰电流差值在0.01～0.8 μmol/L范围内呈现良好的线性关系, 检出限为2.64 nmol/L. 传感器对CH具有很好的选择识别性能.     

How can immunochemical methods contribute to the implementation of the Water Framework Directive?

Immunochemical methods (in particular immunoassays) have been applied to spring and surface water samples, respectively, which were set-up as reference materials (RM) within two proficiency testing campaigns. For the first set of proficiency tests (PTs) described here (which were actually the second round of PTs organized, spring 2005), three ELISAs (enzyme-linked immunosorbent assays) were employed in the enzyme tracer format for isoproturon, diuron, and atrazine, respectively. Results were evaluated in comparison with conventional reference methods (LC, GC). Based on their Z-score laboratory performances, the results for isoproturon and diuron were satisfactory, both for fortified spring water and for the blind solution. The results for atrazine were strongly influenced by other triazines present and needed detailed interpretation. For the second set of PTs described here (which were actually the third round of PTs organized, spring 2006), two ELISAs in the coating antigen format were used for isoproturon and diuron, and the result was included with the results obtained by conventional methods during the PTs. The results (the Z-scores) for isoproturon were again classified as satisfactory, in both fortified surface water and blind solution. The results for diuron in ELISA showed an influence of the water matrix, while the analysis of the blind solution was satisfactory. In addition, an ELISA in the enzyme tracer format was applied to analyze isoproturon, diuron, and atrazine in surface water samples, which had been set-up and spiked during a field trial (tank experiment) at the Maas River at Eijsden, The Netherlands. The immunoassay results were compared with those from an in-house on-line SPE LC/MS–MS used as reference. Although the immunochemical results were sometimes higher than those determined in the reference analysis, the general concentration trends in the samples were similar. The contribution of immunochemical methods to the implementation of the European Water Framework Directive is also discussed.     

Degradation of the herbicide isoproturon by a photocatalytic process

In this study, the adsorption and photocatalytic degradation of isoproturon (one of the most widely used herbicides in agriculture) was investigated in an annular photoreactor packed with a TiO₂ photocatalyst. The results highlighted that the monolayer Langmuir adsorption isotherm model was well obeyed. The isoproturon adsorption equilibrium constant was determined experimentally. The codegradation of isoproturon and of other copollutants such as salicylic acid and phenol occurred, demonstrating that within the catalyst, the same type of sites can be involved in the adsorption of the two pollutants. The heat of adsorption fell in the range of 20 to 50 °C and was found to be ∼43 kJ/mol. As expected, the adsorption constant K_a decreased with increasing the fluid flow due to the temperature rise. The kinetics of the photocatalytic degradation of isoproturon revealed a first-order reaction for initial concentrations between 3 and 43 ppm. In our experimental conditions, no by-products were detected and total disappearance of isoproturon was observed.     

Development and characterisation of a molecularly imprinted polymer prepared by precipitation polymerisation for the determination of phenylurea herbicides

New materials based on molecularly imprinted polymers (MIPs) have been developed for use as sorbents in solid phase extraction to preconcentrate some urea herbicides. In the preconcentration step, different molecularly imprinted polymers were tested using methacrylic acid (MAA) and 2-(trifluoromethyl)acrylic acid (TFMAA) as functional monomers, and linuron and isoproturon as templates. The best results were obtained when the polymer was synthesised using MAA with isoproturon as template. Another parameter evaluated was the way in which the polymer was obtained. We observed that the imprinted polymers obtained by precipitation displayed a greater capacity to retain the phenylureas. Studies conducted using scanning electron microscopy (SEM) revealed that the bulk polymerisation method is far from ideal owing to the random shape and size distribution of the particles obtained, whereas when polymerisation was carried out in precipitation microspheres were obtained. In order to confirm the interaction between the functional monomer and the template, 1H NMR (CD2Cl2) analyses were conducted. The results obtained suggest that the hydrogen and/or nitrogen of the amino group of the template would be involved in the formation of hydrogen bonds with the functional monomer. The imprinted polymer obtained by precipitation polymerisation with MAA as functional monomer and isoproturon as template can be applied to preconcentrate phenylureas when the sample is dissolved in toluene. The proposed methodology was employed to evaluate polymer selectivity towards humic acids and towards other herbicides.     

Determination of phenylureas herbicides in food stuffs based on matrix solid-phase dispersion extraction and capillary electrophoresis with electrochemiluminescence detection

A new method based on matrix solid phase dispersion-capillary electrophoresis with electrochemiluminescence detection (MSPD-CE-ECL) has been developed for the simultaneous determination of three kinds of phenylurea herbicides (PHUs). Poly-β-cyclodextrin (poly-β-CD) was used as an additive in the running buffer to improve the separation of three analytes. The conditions for CE separation, ECL detection and effect of poly-β-CD were investigated in detail. Under the optimal conditions, three kinds of herbicides (isoproturon, linuron and diuron) were well separated and detected within 8 min. The linear ranges of the standard solution for isoproturon and linuron were 1-300 μg L(-1) with a detection limit (S/N=3) of 0.1 μg L(-1), and for diuron was 2-500 μg L(-1) with a detection limit of 0.2 μg L(-1). The average recoveries were in the range of 86.9-102.8%, and all relative standard deviation of the migration time and the ECL intensity in intraday and interday were less than 9.0%. The proposed method was also applied to the determination of three kinds of herbicides in green vegetable and rice samples with recoveries in the range from 78.1 to 93.8%.