基于单壁碳纳米管-DNA酶复合结构的电化学生物传感器

结合DNA酶优异的氧化还原催化特性和碳纳米管的电化学特性, 制备了单壁碳纳米管-DNA酶复合材料, 并通过壳聚糖将其固定到玻碳电极表面构建了电化学生物传感界面. 研究了单壁碳纳米管-DNA酶复合结构的氧化还原反应催化特性, 并以此为传感平台构建了葡萄糖氧化酶电化学生物传感器. 结果表明, 单壁碳纳米管-DNA酶复合材料修饰的电极对过氧化氢的响应具有较宽的线性范围(5×10^-6~1×10^-2 mol/L)和良好的检测灵敏度(检出限为1×10^-6 mol/L). 采用制备的葡萄糖氧化酶传感器实现了对葡萄糖的快速灵敏检测.     

钯/聚苯胺纳米多层膜的制备及对抗坏血酸和多巴胺的催化氧化

采用脉冲电位法(PPSM)结合聚苯胺(PANI)的层层自组装制备了Pd/PANI交替沉积纳米多层膜, 并用于抗坏血酸(AA)和多巴胺(DA)的检测. 实验发现, 多层膜结构形貌及催化性能受前躯体K₂PdCl₆浓度、 脉冲条件及膜厚度等影响. 当K₂PdCl₆浓度为2×10^-3 mol/L, 阴极脉冲电位为-0.3 V, 阶跃次数为17时, 5层Pd/PANI修饰玻碳电极对AA和DA的催化性能最佳; 在0.1 mol/L磷酸盐缓冲液中, AA和DA的氧化峰明显分离[ΔE_p(AA, DA)=160 mV], 其峰电流与浓度分别在5×10^-5～4×10^-4和4×10^-5～1×10^-4 mol/L范围内呈较好线性关系, 实现了对AA和DA的同时测定. 该修饰电极具有良好的抗干扰性和稳定性.     

木犀草素在离子液体修饰电极上的电催化氧化及其测定

用1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF₆)疏水性离子液体修饰玻碳电极,在0.2 mol/L磷酸盐缓冲溶液(pH为4.0～8.0)中,运用循环伏安法（CV）和差示脉冲溶出伏安法(DPSV)研究了木犀草素在修饰电极上的电化学行为,建立了测定木犀草素含量的新方法。 实验结果表明,该修饰电极上木犀草素氧化、还原峰电位均负移,峰电流增大。 在-0.2～0.7 V电位区间,pH=7.0的磷酸盐缓冲溶液体系中,木犀草素在修饰电极表面发生的是受吸附控制的准可逆等电子等质子电极反应,电子转移系数α=0.5,吸附量为4.6×10-10 mol/cm²;木犀草素氧化峰电流与其浓度在1.0×10^-10～1.6×10^-8 mol/L范围内呈良好的线性关系,检出限达到3.2×10^-11 mol/L,回收率为98.7%～102.0%;该法操作简单、快速、灵敏、准确;可用于野菊花中类黄酮的测定。     

吲哚乙酸在纳米金/碳纳米管/壳聚糖修饰玻碳电极上的电化学行为及其检测

以壳聚糖(CS)为多壁碳纳米管(MWNTs)的分散介质, 通过MWNTs/CS膜上大量氨基静电吸附纳米金粒子(nanoAu), 使玻碳电极(GCE)表面形成稳定的nanoAu-MWNTs-CS-GCE修饰层, 并采用电化学方法初步研究了该修饰电极的性能. 探讨了吲哚乙酸(IAA)在该修饰电极上的电化学行为, 结果表明, 在5～200 μmol/L浓度范围内以及0.78 V电位条件下, 以循环伏安法(CV)测得的氧化峰电流变化值与c(IAA)呈良好的线性关系, 其回归方程为y=2.34×10^-4+0.14x, 检出限为8.33×10^-6 mol/L, 相关系数为0.9997.     

D-异抗坏血酸钠热解碳构建电化学传感器检测黄芩素和木犀草素

以廉价易得的D-异抗坏血酸钠为前驱体,通过一步热解法制备了具有三维互连多孔结构的热解碳材料(SDAIPC),利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射(XRD)对材料的形貌和结构进行了表征。结果表明,制备的SDAIPC是一类具有高比表面积的碳材料。以SDAIPC为电极修饰材料,构建了用于同时检测黄芩素(BA)和木犀草素(LU)的电化学传感器。通过电化学交流阻抗谱(EIS)和循环伏安法(CV)研究了传感器的电化学性能;采用微分脉冲伏安法(DPV)研究了BA和LU在不同电极上的电化学行为。在优化条件下,SDAIPC修饰电极对BA和LU进行单独检测时的线性范围为0～8.0μmol/L,检出限(LOD)分别为1.39×10^-9 mol/L和3.02×10^-10 mol/L;对BA和LU进行同时检测时的线性范围为0.05～2.0μmol/L, LOD分别为3.76×10^-9 mol/L和3.78×10^-10 mol/L。该电化学传感器已成功用于BA和LU的实际样品检测。     

纳米银/聚多巴胺修饰玻碳电极的制备及电化学行为

利用电聚合法和脉冲沉积技术制备了纳米银/聚多巴胺修饰的玻碳电极. 通过循环伏安法和示差脉冲伏安法研究了该修饰电极上对硝基苯酚的电化学行为; 讨论了扫描速度和支持电解质等条件对对硝基苯酚在修饰电极上催化还原的影响. 结果表明, 对硝基苯酚的示差脉冲峰电流在4×10^-5～3×10^-4 mol/L范围内呈良好的线性关系.     

高压液相色谱磷钼杂多酸修饰电极安培检测儿茶酚胺类神经递质的研究

研究了磷钼杂多酸修饰电极对去甲肾上腺素(NE)、肾上腺素(E)和多巴胺(DA)等儿茶酚胺类神经递质的催化氧化作用,探讨了催化机理,并采用高压液相色谱电化学方法对其进行了分离检测,NE、DA和E的线性范围(mol)依次为8.0×10^-11～2.0×10^-8、8.0×10^-11～2.0×10^-8、4.0×10^-11～2.0×10^-8;检测限(mol))依次为4.0×10^-11、4.0×10^-11、2.0×10^-11.7次平行测定的相对标准偏差(％)依次为1.6、2.0和4.5.将此法用于鼠脑组织中神经递质的测定,获得满意的结果.     

石墨烯/铁氰化钴复合膜修饰玻碳电极同时测定对苯二酚、邻苯二酚和间苯二酚

采用滴涂法和电沉积法制备了石墨烯/铁氰化钴复合膜修饰玻碳电极. 用扫描电镜对该纳米复合膜进行了表征.用循环伏安法研究了对苯二酚(HQ)、邻苯二酚(CT)和间苯二酚(RS)在修饰电极上的电化学行为. 实验结果表明, 相对于裸玻碳电极和石墨烯修饰电极, HQ, CT 和RS 在石墨烯/铁氰化钴修饰电极上的氧化峰电流显著提高. 利用差分脉冲伏安法测定, HQ, CT 和RS 分别在1.0×10^－6～1.5×10^－4 mol/L, 1.0×10^－6～2.0×10^－4 mol/L 和3.5×10^－6～2.5×10^－4 mol/L浓度范围内与氧化峰电流呈良好的线性关系, 相关系数分别为0.991, 0.993 和0.992. 信噪比为3 时, HQ, CT 和RS 检出限分别为2.0×10^－7, 2.1×10^－7 和3.5×10^－7 mol/L. 将该方法用于水样分析, 回收率为95.6%～106.1%.     

基于拮抗作用检测除草剂的类囊体膜生物传感器研究

利用除草剂对植物类囊体束缚酶分解过氧化氢的拮抗作用,研制了一种快速检测痕量除草剂的电化学生物传感器.将植物类囊体用聚乙烯醇-苯乙烯吡啶(PVA-SbQ)光敏聚合剂在紫外光诱导下产生大分子网状结构进行包埋,制成生物敏感膜,并固定在铂电极表面.根据加入除草剂时类囊体膜束缚酶分解过氧化氢活性的变化,对除草剂进行测定.在含有1×10^-3mol/LNaCl,5×10^-3mol/LMgCl₂和0.01mol/LH₂O₂的Tris-HCl缓冲溶液(pH=7.4)中,基于测量0.65V处H₂O₂氧化电流的变化,可以对下列浓度的除草剂进行定量检测:百草枯3×10^-9～1.5×10^-7mol/L,敌草龙1×10^-8～3×10^-7mol/L,扑草净4×10^-8～3×10^-6mol/L,阿特拉津1×10^-7～5×10^-6mol/L,莠灭净1×10^-7～5×10^-6mol/L.利用PVA-SbQ光聚合膜固定类囊体,能够使酶的活性在低温下保持数月.     

基于聚乙烯醇离子液体负载HRP修饰石墨烯/纳米金复合膜的过氧化氢生物传感器

以石墨烯/纳米金修饰玻碳电极为基底, 用聚乙烯醇与离子液体复合物将辣根过氧化物酶固定于电极表面, 制备了过氧化氢生物传感器. 结果表明, 在0.1 mol/L HAc-NaAc+0.1mol/L KCl(pH=6.5)中, H₂O₂的氧化峰电流与其浓度在9.55×10^-6~6.01×10^-3 mol/L间呈良好线性关系, 检出限(3S/N)为3.3×10^-7 mol/L. 用标准加入法做回收实验, 回收率在93.4%~100.5%之间. 该传感器对H₂O₂具有较高的灵敏度和较低的检测限, 稳定性和重现性良好, 使用寿命较长, 且制作成本低, 可多次重复使用.     

Electrochemical Study and Application on Shikonin at Poly(diallyldimethylammonium chloride) Functionalized Graphene Sheets Modified Glass Carbon Electrode

The electrochemical behaviors of shikonin at a poly(diallyldimethylammonium chloride) functionalized graphene sheets modified glass carbon electrode(PDDA-GS/GCE) have been investigated. Shikonin could exhibit a pair of well-defined redox peaks at the PDDA-GS/GCE located at 0.681 V(E_pa) and 0.662 V(E_pc)[vs. saturated calomel electrode(SCE)] in 0.1 mol/L phosphate buffer solution(pH=2.0) with a peak-to-peak separation of about 20 mV, revealing a fast electron-transfer process. Moreover, the current response was remarkably increased at PDDA-GS/GCE compared with that at the bare GCE. The electrochemical behaviors of shikonin at the modified electrode were investigated. And the results indicate that the reaction involves the transfer of two electrons, accompanied by two protons and the electrochemical process is a diffusional-controlled electrode process. The electrochemical parameters of shikonin at the modified electrode, the electron-transfer coefficient(α), the electron-transfer number(n) and the electrode reaction rate constant(k_s) were calculated to be as 0.53, 2.18 and 3.6 s^-1, respectively. Under the optimal conditions, the peak current of differential pulse voltammetry(DPV) increased linearly with the shikonin concentration in a range from 9.472×10^-8 mol/L to 3.789×10^-6 mol/L with a detection limit of 3.157×10^-8 mol/L. The linear regression equation was I_p=0.7366c+0.7855(R=0.9978; I_p: 10^-7 A, c: 10^-8 mol/L). In addition, the modified glass carbon electrode also exhibited good stability, selectivity and acceptable reproducibility that could be used for the sensitive, simple and rapid determination of shikonin in real samples. Therefore, the present work offers a new way to broaden the analytical application of graphene in pharmaceutical analysis.     

Studies on the Voltammetric Behavior of Nicardipine Hydrochloride,its Voltammetric Determination at the Co/GC Modified Electrode

To whom correspondence should be addressed. In a 0.02 mol/L BR buffer solution(pH=5.52), the electrochemical behaviour of nicardipine hydrochloride was studied by linearsweep voltammetry, cyclic voltammetry at a Co/GC ion implantation modified electrode. The experiments showed that the electrode had a good stability, reproductivity. The peak height was proportional to the concentration of nicardipine over the range of 4.0×10^-7—1.0×10^-4 mol/L, the detection limit was 1.0×10^-7 mol/L. This method has been used for the direct determination of nicardipine in tablets. Its recoveries were in the range from 95.6% to 103.8%. The reduction of nicardipine at the Co/GC electrode was an irreversible proccess.     

Gold nanoparticles-enhanced bisphenol A electrochemical biosensor based on tyrosinase immobilized onto self-assembled monolayers-modified gold electrode

A novel electrochemical sensor based on the immobilization of tyrosinase(tyr) onto gold nanoparticles(nano-Au) and thioctic acid amide(T-NH2) self-assembled monolayers(SAMs)-modified gold electrode has been developed for the determination of bisphenol A(BPA).It was found that the nano-Au could significantly enhance the electrochemical response of tyr/nano-Au/T-NH2/Au electrode to BPA,and the enhancement effect of nano-Au on the current response was also related to the enzyme.The results indicated that the biosensor could be used as a detector for BPA determination with a linear range from3.99 ×10-7mol/L to 2.34 ×10-4mol/L and a detection limit of 1.33×10-7mol/L.In addition,this biosensor showed good reproducibility.     

石墨烯修饰玻碳电极在对苯二酚存在下选择性测定米吐尔

制备了石墨烯修饰玻碳电极(GN/GCE)。 在0.5 mol/L HAc-NaAc(pH=4.8)缓冲溶液中,用循环伏安法(CV)和方波伏安法(SWV)研究了米吐尔在修饰电极上的电化学行为,建立了测定米吐尔的新方法。 研究表明,米吐尔在GN/GCE上的氧化、还原峰电势差比其在裸玻碳电极(GCE)上的小,峰电流显著增加,说明GN/GCE对米吐尔有电催化作用;共存物对苯二酚干扰米吐尔的测定,通过方波伏安法可以消除其干扰。 在方波伏安曲线上,米吐尔的还原峰电流与其浓度在8.0×10^-8~5.0×10^-5 mol/L范围内呈线性关系,检出限为2.0×10^-8 mol/L。 该法可用于照相显影废液中米吐尔的测定。     

Electrochemical Behavior of Mitoxantrone and Its Determination at a Pt／C Implanted Modified Microelectrode

In a 0.02 mol/L Na2HPO4-KH2PO4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was -0.72 V(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10-8-9.0×10-7 mol/L and 1.0×10-6-2.4×10-5 mol/L, with a detection limit of 4.0×10-8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant ks and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s-1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility.     

化学发光新体系NaIO4-H2O2-痕量环己烷-多羟基酚的研究及其应用

近年来,一些无机氧化剂在氧化有机物时伴随的化学发光现象引起了分析工作者的广泛兴趣[1,2].NaIO4氧化H2O2会产生弱化学发光,不同的多羟基酚类物质能不同程度地增强这一化学发光行为,据此建立了测定多羟基酚的化学发光法.目前,利用该法测定的酚主要有苯酚[3]、酚的衍生物[4]和连苯三酚[5,6].本文建立的测定连苯三酚的方法检测限较王伦等[3]的利用苯酚对Luminol-H2O2发光体系猝灭作用测定工业废水及Ermiridis[5]以IO4-在碱性介质中直接氧化连苯三酚的检测限低两个数量级,且扩大了测定酚的种类.研究发现,一些非极性有机溶剂对这一化学发光亦有增强和增稳作用,而痕量非极性溶剂由于在水中的溶解性较差,对化学发光的作用尚未受到注意.     

氨甲蝶呤在Co/GC离子注入修饰电极上电化学行为及其应用研究

氨甲蝶呤在0.1mol/LHAc-NaAc(pH=4.96)缓冲溶液中,用Co/GC离子注入修饰电极进行伏安测定,得到一良好的还原峰,峰电位为-0.95V(vs.SCE).峰电流Ip与氨甲蝶呤的浓度在2.2×10^-7～8.8×10^-6mol/L范围内呈线性关系。检出限为1.1×10^-8mol/L.建立了测定氨甲蝶呤的新方法,可用于实际样品的测定,回收率在98.9%～106.2%之间。用线性扫描和循环伏安法研究了体系的电化学行为及电极反应机理。实验表明,氨甲蝶呤的还原为不可逆吸附过程,并伴随两个电子和两个氢离子参与电极反应。用俄歇电子能谱(AES)和X射线光电子能谱(XPS)等表面分析技术对Co离子注入修饰电极的表面元素组成及深度分布等进行测定,表明Co离子确被注入到玻碳表面。扫速对催化效率的影响实验证明体系存在催化作用。     

吡柔比星在钴离子注入修饰微电极上电化学行为及其应用

吡柔比星在0.1mol/LHAc-NaAc(pH=5.05)缓冲溶液中,用Co离子注入修饰碳纤维微电极进行研究,得到一良好的还原峰,峰电位Ep=-0.520V(vs.SCE).峰电流与吡柔比星浓度在1.0×10^-7～6.0×10^-6mol/L范围内成线性关系,检出限为5.0×10^-8mol/L.用于病人尿样测定,回收率在91.6%～106.7%之间.吡柔比星的还原为可逆吸附过程,伴随着两个电子、两个氢离子参加电极反应.用扫描电子显微镜(SEM)和俄歇电子能谱(AES)两种表面分析技术对Co离子注入修饰微电极的表面状况、表面元素组成及深度分布进行测定.实验表明,Co离子确实被注入到碳纤维表面上.扫速对催化效率的影响实验证明体系存在催化作用.     

Highly Sensitive and Selective Amperometric Sensor for Iodate Based on 9,10-Phenanthrenequinone Derived Graphene

We reported on a new amperometric sensor for the sensitive and selective determination of iodate in table salt. The iodate sensor was constructed by the integration of a novel nanocomposite which was made from 9,10-phenanthrenequinone(PQ) and graphene(GP) with a glassy carbon electrode(GCE). The synthesized graphene and the nanocomposite were well characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), Fourier transform infrared(FTIR) spectroscopy and Raman spectroscopy. We fully studied the electrochemical behavior and kinetic characteristics of the PQ/GP nanocomposite at GCE. The PQ/GP electrode shows a good electrochemical catalytic activity towards the reduction of iodate, which makes itself a sensitive and selective electrochemical sensor for iodate. The iodate sensor displays a high sensitivity(1.04 mA·mmol·L^-1), a low detection limit(1.0×10^-8 mol/L), a rapid response(less than 2 s), and a broad linear range(from 5.0×10^-8 mol/L to 6.0×10^-3 mol/L ). In addition, the sensor is interference free. The practical application of the proposed sensor was tested by the detection of iodate in table salt.