氯霉素分子印迹复合膜的制备及电化学

采用电化学聚合法合成了对氯霉素（CAP）有快速响应和高灵敏度的聚苯胺/聚吡咯分子印迹复合膜修饰电极。 通过微分脉冲伏安法、扫描电子显微镜对制备的分子印迹复合膜的电化学性质及表面形貌进行了表征。 结果表明,以铁氰化钾为电化学探针,该膜对CAP的测定电化学信号响应快速、灵敏度高、选择性和膜再生性能良好。 对CAP检测的线性范围为5.00×10-8～1.05×10-6 mol/L,检测限为2.09×10-9 mol/L。     

纳米金-二氧化钛纳米针修饰电极用于氯霉素检测

将金胶-TiO2纳米针修饰玻碳(Au-TiO2/GC)电极用于对氯霉素(CAP)浓度的电化学测定。 结果表明,在0.1 mol/L pH=7.0的磷酸盐缓冲溶液(PBS)体系中,CAP在Au-TiO2/GC电极上有较好的电化学响应,CAP浓度在8.0×10-7～1.0×10-4 mol/L范围内,峰电流与其浓度呈良好的线性关系,检出限为7.8×10-8 mol/L。 并对氯霉素滴眼液中CAP浓度进行了检测,发现该方法有高的检测灵敏度、好的重复性和抗干扰性,且操作简便、成本低廉。     

氯丙嗪分子印迹敏感膜传感器的制备与应用

以氯丙嗪为模板分子,邻氨基酚为功能单体,在金电极表面电聚合制备具有特异性识别孔穴的氯丙嗪分子印迹敏感膜(MIP)。 采用循环伏安法(CV)、差分脉冲伏安法(DPV)等研究了印迹膜的性能、结构和分子印迹效应,并与其结构相似的化合物奋乃静和异丙嗪的选择性响应进行了比较,发现传感器对氯丙嗪具有良好的选择性。 氯丙嗪浓度在6.0×10-7～9.0×10-5 mol/L范围内与峰电流呈线性关系,线性方程为:I(μA)=61.25lg c(μmol/L)+23.47(r=0.9975),根据DL=3δb/s计算检出限为2.0×10-7 mol/L,该传感器具有良好的重复性、再生性和高灵敏度。     

自组装碳纳米管-氯洁霉素分子印迹溶胶-凝胶电化学传感器研究

结合自组装技术, 采用电聚合方法在碳纳米管修饰金电极表面制备对氯洁霉素具有特异性识别位点的分子印迹溶胶-凝胶薄膜, 成功构建了一种新型印迹溶胶-凝胶电化学传感器. 通过循环伏安法(CV)、示差脉冲法(DPV)、安培计时法(I-t)和扫描电镜(SEM)表征了该印迹溶胶-凝胶膜的电化学性能和表面形貌. 结果表明, 该传感器具有良好的选择性和灵敏度, 氯洁霉素在多壁碳纳米管修饰的印迹溶胶-凝胶传感器上的响应明显提高. 该印迹溶胶-凝胶传感器对氯洁霉素的浓度响应线性范围为5.0×10^-7~8.0×10^-5 mol/L, 检出限为2.44×10^-8 mol/L. 该传感器被成功地用于人体尿液中氯洁霉素的分析测定.     

L-色氨酸分子印迹传感器敏感膜的制备与性能

以L-色氨酸(L-Trp)为模板分子, 邻苯二胺(o-PD)为功能单体, 在金电极表面原位合成了分子印迹聚合物敏感膜; 通过循环伏安法(CV)、 差示脉冲伏安法(DPV)和电化学阻抗谱法(EIS)考察了该电极的性能. DPV测试结果表明, 在1×10^-8~2×10^-7 mol/L范围内, 峰电流与L-Trp的浓度呈线性关系, 检出限为0.3×10^-8 mol/L; 选择识别性实验结果表明, L-Trp印迹敏感膜的印迹因子达到3.72, 相对于干扰物的选择因子均大于1, 对与L-Trp结构相似的L-酪氨酸(L-Tyr)的选择因子也达到2.30, 说明该印迹膜对L-Trp具有良好的选择性; 识别过程动力学研究结果表明, 印迹膜对L-Trp的识别是一个两步连续发生的过程, 即快结合过程和慢吸附过程.     

聚苯胺-邻氨基酚膜修饰电极的制备及其应用

通过循环伏安法(CV)将苯胺(AN)-邻氨基酚(OAP)修饰在玻碳电极(GCE)表面,制备出聚苯胺-邻氨基酚聚合物膜修饰电极(PAN-OAP/GCE),并用该电极对抗坏血酸(AA)进行测定。分别对OAP与AN聚合浓度比和磷酸缓冲溶液(PBS)pH进行优化。结果表明OAP与AN浓度比为1:14,pH为6.80时,所得聚合物膜修饰电极具有良好的电化学催化活性和稳定性。同时,在0.1 mol/L PBS(pH 6.80)中,采用差分脉冲伏安法(DPV)对AA进行测定,结果表明PAN-OAP/GCE电极对AA具有明显的电化学催化氧化作用,且AA在膜修饰电极上的响应电流和其浓度在1.50×10-8～2.12×10-6mol/L范围内呈良好的线性关系,线性回归方程为ip=1.0344c+0.0183,相关系数为0.9988。检测限可达5.0×10-9mol/L。该修饰电极具有较高的灵敏度和选择性,用于样品中AA的检测,回收率为96.0%～101.2%。     

基于分子印迹膜修饰丝网印刷电极的地西泮电化学传感器

以地西泮为模板分子,采用循环伏安法在一次性丝网印刷电极表面原位电聚合形成聚邻苯二胺膜,洗脱除去模板分子后得到地西泮分子印迹膜修饰丝网印刷电极。利用差示脉冲法对印迹膜和非印迹膜进行评价,表征了电极表面膜的电化学性质。以KI为印迹电极和底液间的探针,建立了一种间接检测地西泮的传感方法。该传感器的敏感元件为修饰有分子印迹膜的丝网印刷电极,其制备和更换非常方便。用于电化学检测时,样品的富集时间为3min,地西泮的浓度在2.0×10-7～1.0×10-5mol/L范围内与峰电流呈良好的线性关系,检出限为2.5×10-8mol/L,基于猪肉样品的加标回收率为92%～95%。将该传感器初步用于实际样品分析,结果满意。     

利巴韦林原位聚合分子印迹电化学传感器的研制

利用原位聚合分子印迹技术,以3-氨基苯硼酸(3-ABBA)为功能单体,利巴韦林(RIB)为目标分子,以硼酸和顺式二醇在不同酸碱度条件下可逆形成环内酯键为原理,在玻碳电极表面原位聚合形成利巴韦林分子印迹膜,研制了测定利巴韦林的分子印迹电化学传感器。采用循环伏安法(CV)和差分脉冲法(DPV)对印迹膜性能进行研究。DPV测试表明:在最优实验条件下,利巴韦林的浓度在5.0×10~(-8)~1.0×10~(-5)mol/L范围内与峰电流呈良好的线性关系,相关系数(r~2)为0.995 3,检出限(S/N=3)为1.5×10~(-8)mol/L。特异性实验表明制备的传感器对利巴韦林的选择性良好。该分子印迹电化学传感器可用于食品中利巴韦林的检测。     

抗坏血酸分子印迹电化学传感器的研制与应用

以抗坏血酸(AA)为模板分子,邻苯二胺(o-PD)为功能单体,采用循环伏安法(CV)在玻碳电极表面电聚合形成聚邻苯二胺(PPD)膜,经水将模板分子洗脱后,制得抗坏血酸分子印迹膜电极。优化的分子印迹条件为:以0.20 mol/L HAc-NaAc(pH 5.2)缓冲溶液为反应介质,o-PD和AA的摩尔比为1∶2,扫描电位为0~0.8 V,扫描速度为50 mV/s。利用CV、方波伏安法(SWV)和电流-时间曲线法(I~t)对该分子印迹传感器的电化学性能进行评价。该传感器的响应电流与AA浓度在低浓度区(1.0×10-6~1.0×10-3mol/L)和高浓度区(1.0×10-3~4.5×10-3mol/L)分别呈良好的线性关系,检出限为4.9×10-7mol/L。运用建立的方法对市售橙汁中的AA进行测定,并用2,6-二氯酚靛酚滴定法进行验证,结果表明,该传感检测技术快速、准确、成本低,适用于橙汁等食品中AA的测定。     

分子印迹聚合物修饰电化学晶体管检测抗坏血酸分子

以抗坏血酸(AA)为模板分子、邻苯二胺(o-PD)为功能单体,在金电极表面电聚合制备分子印迹聚合物膜(MIP),并以该MIP修饰的电极为栅极制备了具有高选择性、高灵敏度的AA电化学晶体管(OECT)传感器件。应用循环伏安法(CV)、交流阻抗法(EIS)对分子印迹聚合物电极进行一系列的表征与检测。实验结果表明:以pH=5.2,浓度为0.2mol/L HAc-NaAc(体积比2.1∶7.9)的缓冲液为背景溶液,o-PD与AA的物质的量之比为1∶2,以0.5V/s的扫描速率在0~0.8V内扫描20圈,所得分子印迹膜电极性能最佳。应用以该分子印迹修饰电极作为栅极的电化学晶体管检测AA,得到AA浓度的检测限为0.3μmol/L,沟道电流与AA浓度在0.3~3μmol/L(低浓度)与3~100μmol/L(高浓度)这2个范围内成线性关系。     

Pt/C和Pt/CNTs电极的电化学稳定性研究

采用恒电位氧化法研究了Pt/C和Pt/CNTs电极的电化学稳定性. 相同条件下, Pt/C电极的氧化电流大约为Pt/CNTs电极的2倍; 120 h氧化后, Pt/C电极Pt的电化学表面积下降了21.3%, 而Pt/CNTs电极仅下降了7.6%, 表明Pt/CNTs电极性能衰减较慢. X射线光电子能谱(XPS)分析表明, Pt/C的载体碳黑表面氧增加量大于Pt/CNTs中碳纳米管(CNTs)表面氧的增加量, 说明碳黑的被氧化程度较高, 电化学稳定性差; Pt的表面化学状态没有发生变化; 碳纳米管本身的抗电化学氧化性也大于碳黑. 所以, 载体的被氧化程度不同是两种电极性能衰减不同的主要原因之一, 并且排除了Pt表面状态的影响.     

Capillary electrophoresis enzyme immunoassay for alpha-fetoprotein and thyroxine in human serum with electrochemical detection

A novel CE-based enzyme immunoassay (CE-EIA) method was developed in o-aminophenol (OAP)-H(2)O(2)-horseradish peroxidase (HRP) system and applied to benign liver disease and hyperthyroidism research in the clinical practical field. In the presented method, after the enzyme immunoreaction, the HRP-labeled antibody or HRP-labeled antigen catalyzed the enzyme substrate OAP and H(2)O(2). The product of the enzymatic catalysis reaction 2-aminophenoxazine-3-one (AP) was determined using electrochemical detection on a Pt electrode at the outlet of the reaction capillary. Factors influencing the performance, including running buffer concentration, separation, and detection voltage, were investigated to the optimum conditions. Noncompetitive and competitive models were utilized to detect alpha-fetoprotein (AFP) and thyroxine (T(4)) in human sera, respectively. The linear ranges and the detection limits (S/N = 3) were from 1.5 to 66.6 ng/mL and 0.48 ng/mL for AFP, and from 1.7 to 260.0 ng/mL and 1.0 ng/mL for T(4). The results of this method were linear proportional to those of spectrophotometric ELISA method, giving a good prospect for a new clinical diagnostic instrument.     

Separation/Concentration‐signal‐amplification in‐One Method Based on Electrochemical Conversion of Magnetic Nanoparticles for Electrochemical Biosensing

We propose a separation/concentration‐signal‐amplification in‐one method based on electrochemical conversion (ECC) of magnetic nanoparticles (MNPs) to develop a facile and sensitive electrochemical biosensor for chloramphenicol (CAP) detection. Briefly, aptamer‐modified magnetic nanoparticles (MNPs‐Apt) was designed to capture CAP in sample, then the MNPs‐Apt composite was conjugated to Au electrode through the DNA hybridization between the unoccupied aptamer and a strand of complementary DNA. The ECC method was applied to transfer MNPs labels to electrochemically active Prussian blue (PB). The anodic and cathodic currents of PB were taken for signal readout. Comparing with conventional methods that require electrochemically active labels and related sophisticated labelling procedures, this method explored and integrated the magnetic and electrochemical properties of MNPs into one system, in turn realized magnetic capturing of CAP and signal generation without any additional conventional labels. Taking advantages of the high abundance of iron content in MNPs and the refreshing effect deriving from ECC process, the method significantly promoted the signal amplification. Therefore, the proposed biosensors exhibited linear detection range from 1 to 1000 ng mL⁻¹ and a limit of detection down to 1 ng mL⁻¹, which was better than or comparable with those of most analogues, as well as satisfactory specificity, storage stability and feasibility for real samples. The developed method may lead to new concept for rapid and facile biosensing in food safety, clinic diagnose/therapy and environmental monitoring fields.     

聚苯胺分子印迹膜电化学传感器检测氯霉素

以苯胺为功能单体和交联剂,氯霉素(chloramphenicol,CAP)为模板分子,采用电化学聚合法(循环伏安法)在金电极上合成了对CAP具有快速响应能力的聚苯胺分子印迹膜;结合差示脉冲伏安法建立了针对氯霉素的检测方法,并将所制备的聚苯胺分子印迹膜用作电化学传感器以测定氯霉素眼药水中的氯霉素.结果表明,所制备的聚苯胺分子印迹膜具有制备简单、响应快速、灵敏度高、再生性能良好等特点;其对氯霉素眼药水中的氯霉素的检测结果令人满意,有望用于实际样品中氯霉素的检测.     

纤维蛋白原在Pt电极上的界面电化学研究

应用电化学方法和电化学原位红外反射光谱(electrochemical in-situ FTIR)等研究了纤维蛋白原在Pt电极上的界面电化学行为.结果表明:纤维蛋白原在Pt电极上的吸附使电极的析氢与氧脱附过程减弱,影响程度随扫速的增加而增强;同样纤维蛋白原的吸附会降低亚铁氰化钾-铁氰化钾电对的氧化还原反应可逆性和电流;在-0.1~0.6V(vs.SCE)扫描范围内没有出现纤维蛋白原的特征"氧化还原"峰.电化学原位红外反射光谱测试表明纤维蛋白原在0.3~0.5V(vs.SCE)间发生化学反应,有新的产物生成.     

碳纳米管电极上原位沉积Pt纳米颗粒

 本文利用原位离子交换法制备了碳纳米管(CNTs)载铂(Pt/CNTs)电极. X射线光电子能谱分析表明, Pt通过离子交换载于电化学功能化的CNTs表面. 扫描电镜照片显示, Pt高度分散于CNTs表面. X射线衍射分析表明, Pt的粒径约为4.0 nm. 离子交换法所制Pt/CNTs电极的电化学表面积和Pt的利用率均大于传统Pt/CNTs电极(Pt粒径约为2.5 nm), 其对氧还原的催化活性高于传统电极. 这归因于离子交换法所制电极的特殊结构,即Pt普遍载于电化学活性位上.     

Pt/SPE电极的制备及其电化学性能

固态电解质;Pt/SPE电极的制备及其电化学性能     

Highly Sensitive Molecularly Imprinted Sensor Based on Platinum Thin‐film Microelectrode for Detection of Chloramphenicol in Food Samples

A highly sensitive and selective electrochemical biomimetic sensor was fabricated for fast detection of chloramphenicol (CAP) in honey and milk samples. Platinum thin‐film microelectrode (Pt TFME), which could provide unique electrochemical properties and achieve measurement using very limited solution volumes, was surface‐modified by electropolymerizing o‐phenylenediamine. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the preparation process of CAP‐imprinted poly(o‐phenylenediamine) film and rebinding ability of CAP into the imprinted cavities. The electrochemical properties of the sensor were further investigated with square wave voltammetry (SWV) by using K₃Fe(CN)₆ as an electroactive probe. The current difference of oxidation peaks of K₃Fe(CN)₆ had a good linear relationship with the concentration of CAP in the range of 0.9–10 nM. The detection limit was 0.39 nM based on the signal to noise ratio of 3. The developed sensor was successfully applied to determine CAP in honey and milk samples, and the result was in good agreement with that obtained by high performance liquid chromatography‐mass spectrometry (HPLC‐MS). The sensor showed high sensitivity and excellent selectivity to CAP in comparison to other structurally related and/or normally existing antibiotics, and demonstrated great promise for the rapid quantification of CAP in real food samples and field analysis.     

“卡房”结构LDHs负载Pt纳米催化剂用于乙醇电催化氧化

乙醇电催化氧化是直接乙醇燃料电池(DEFCs)的核心反应,而DEFCs的阳极电催化剂是提升乙醇转化效率的关键。Pt作为最稳定、最有效的催化剂之一,仍面临着成本高、容易被乙醇氧化产生的中间产物毒化等问题。选择合适的载体实现Pt的高度、均匀、稳定分散,不仅可以提高其抗中毒能力和催化活性,而且还可以减少Pt用量降低成本。本文采用两步电化学沉积法合成了层状双金属氢氧化物(LDHs)纳米阵列负载Pt纳米催化剂(Pt/LDHs/NF),具有“卡房”结构的LDHs增强了Pt纳米粒子的分散,有助于实现高效的乙醇电催化氧化性能。制备的Pt/NiFe-LDH/NF在碱性环境下对乙醇表现出最优的电催化氧化活性,峰值电流密度达到171.99mA·cm^-2。这可为今后设计和制备均匀、稳定分散的Pt基催化剂用于乙醇电催化氧化提供借鉴。