磺基水杨酸修饰电极联吡啶钌电化学发光体系测定可待因的研究

基于磷酸可待因对联吡啶钌在该电极上的电化学及其发光行为的增敏作用,建立了一种直接测定磷酸可待因的电化学发光新方法。在最佳实验条件下,磷酸可待因在1.0×10-4～4.0×10-6mol/L和4.0×10-6～2.0×10-7mol/L与相对发光强度呈线性关系,检出限为1.0×10-7mol/L(S/N=3)。连续测定4.0×10-7mol/l磷酸可待因5次,发光强度的RSD为2.7%。方法用于模拟尿样中磷酸可待因的测定,结果满意。     

对硫磷在纳米氧化铝薄膜修饰电极上的电化学行为及其测定

制备了纳米氧化铝修饰玻碳电极(nano-Al2O3/GCE/CME),用循环伏安法(CV)、线性扫描伏安法(LSV)研究了对硫磷(TP)在nano-Al2O3/GCE/CME上的电化学行为.实验表明,该修饰电极与裸电极相比能显著提高TP的氧化还原峰电流并降低其氧化峰电位.在0.1 mol/L HAc-NaAc缓冲溶液(pH =5)中,TP在该修饰电极上产生1个不可逆的还原峰( Epc1=-0.567 V)和1对可逆氧化还原峰( Epa2=0.018 V和Epc2=-0.008 V) ,氧化峰电流与TP的浓度在2.5×10-9～1.0×10-7 mol/L和1.0×10-7～1.0×10-5 mol/L范围内具有良好的线性关系,回归方程分别为: ip(μA)=0.2529+4.201C(μmol/L), r=0.9984和ip(μA)=0.6752+0.3181C(μmol/L), r=0.9946.开路富集30 s后,检出限为1.0 ×10-9 mol/L(S/N=3).在1.0×10-5 mol/L TP试液中连续测定10次,其RSD为3.8%.用此方法测定了蔬菜中TP的含量,回收率为95. 6%～100.5% ,结果满意.     

Amperometric determination of 6-mercaptopurine on functionalized multi-wall carbon nanotubes modified electrode by liquid chromatography coupled with microdialysis and its application to pharmacokinetics in rabbit

In this paper, multi-wall carbon nanotubes fuctionalized with carboxylic groups modified electrode (MWNT-COOH CME) was fabricated. This chemically modified electrode (CME) can be used as the working electrode in the liquid chromatography for the determination of 6-mercaptopurine (6-MP). The results indicate that the CME exhibits efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP are linear to its concentrations ranging from 4.0×10⁻⁷ to 1.0×10⁻⁴ mol l⁻¹ with the calculated detection limit (S/N=3) of 2.0×10⁻⁷ mol l⁻¹. Coupled with microdialysis, the method has been successfully applied to the pharmacokinetic study of 6-MP in rabbit blood. This method provides a fast, sensible and simple technique for the pharmacokinetic study of 6-MP in vivo.     

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%.     

Electrochemical determination of 6-mercaptopurine at silver microdisk electrodes

The electrochemical behaviour of 6-mercaptopurine (6-MP) at a microdisk electrode is investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that 6-MP can be strongly adsorbed on the surface of the static mercury drop electrode (SMDE) and reacts with Ag+ ions which are produced at positive potentials. 6-MP yields a well-defined cathodic stripping signal during the negative scan at about -0.812 V (vs. SCE) in pH 9.0 phosphate buffer solution. The electrode has hence been used for the determination of 6-MP by differential pulse voltammetry (DPV). The linear range is between 2.0x10(-7) and 5.0x10(-5) mol/l, with the calculated detection limit (S/N=3) of 8.0x10(-8) mol/l. The relative standard deviation is 3.0% for eight successive determinations of 4.0x10(-5) mol/l 6-MP. The determination of 6-MP in tablets has also been carried out and satisfactory results have been obtained.     

Captopril Modified Silver Electrode and Its Application to the Electroanalysis of Hemoglobin

Abstract

Captopril, 1-[(2S)-3-mercapto-2-methyl-1-oxopropyl]-L-Proline, can be deposited onto a silver electrode by a covalent bonding method to give a long-lived and stable chemically modified electrode(CME). Since the CME is prepared with a reaction between captopril and the substrate silver, the CME being prepared by this method is very stable. Furthermore, Hemoglobin(Hb) exhibits excellent voltammetric response at the modified electrode. Differential pulse voltammetric(DPV) measurements of the protein with this CME reveal the existence of a linear relationship between the anodic peak current and the concentration of Hb in the range of 2×10^?6 ～ 5×10^?5 mol/L. The detection limit is 8×10^?7 mol/L and the relative standard deviation of results is 5% for 6 successive determinations at 2×10_-5 mol/L. The determination of Hb for a real example is carried out.     

氧化石墨烯/铁氰化铈修饰玻碳电极同时测定扑热息痛和咖啡因

采用滴涂法和电沉积法制备了氧化石墨烯/铁氰化铈(CeFe(CN)6)纳米复合膜修饰玻碳电极。用扫描电镜对氧化石墨烯和氧化石墨烯/CeFe(CN)6纳米复合膜进行了表征。分别用循环伏安法和差分脉冲伏安法研究了扑热息痛和咖啡因在修饰电极上的电化学行为。结果表明,在0.1 mol/L醋酸盐缓冲溶液(pH5.0)中,扑热息痛和咖啡因在此修饰电极上具有良好的电化学行为,扑热息痛和咖啡因分别在1.0×10-7～6.0×10-5mol/L和1.0×10-6～1.3×10-4mol/L浓度范围内与电化学响应信号呈良好的线性关系,相关系数分别为0.990和0.992;信噪比为3时,扑热息痛和咖啡因检出限分别为5.0×10-8mol/L和5.2×10-7mol/L。将本方法用于人尿样品分析,回收率为96.1%～105.4%。     

维生素B6在维生素B12修饰电极上的电化学行为及其分析应用

采用循环伏安法研究了维生素B6在维生素B12修饰玻碳电极上的电化学行为,建立了测定痕量维生素B6的新方法.在pH 8.6的NH3-NH4Cl缓冲溶液中,维生素B6在修饰电极上产生一个灵敏的氧化峰,采用差分脉冲伏安法测定,其氧化峰电流与维生素B6的浓度在8.0×10-7～2.0×10-4 mol/L范围内呈良好的线性关系,检出限为2.0×10-7 mol/L.该修饰电极具有良好的选择性、灵敏度及稳定性,用于片剂中维生素B6的定量分析,结果令人满意.     

2,5-巯基-1,3,4-硫代二氮唑自组装金电极测定银(I)

制备了2,5-巯基-1,3,4-硫代二氮唑(DMTD)自组装单分子层修饰金电极,用电化学阻抗谱进行了表征,研究了Ag(I)在该电极上的电化学行为并用差分脉冲阳极溶出伏安法对其进行了测定。结果表明,DMTD/Au电极能显著提高Ag(I)测定的灵敏度和选择性,Ag(I)浓度在9.4×10-7～8.0×10-6mol/L范围内,氧化峰电流与Ag(I)呈现良好的线性关系,检出限为2×10-7 mol/L。该自组装电极可用于水样的测定。     

聚伊文思蓝修饰电极对多巴胺和抗坏血酸的电分离及同时测定

研究多巴胺(DA)和抗坏血酸(AA)在聚伊文思蓝(Evans Blue)修饰电极上的伏安行为,建立差示脉冲伏安测定法.在pH4.5磷酸盐缓冲液中,聚伊文思蓝修饰电极对DA和AA有显著的增敏和电分离作用.DA和AA氧化峰电流与浓度分别在1.0×10-6~3.0×10-5mol/L和5.0×10-6~1.05×10-4mol/L范围内呈良好的线性关系,检测限分别为2.5×10-7mol/L和3.0×10-7mol/L.当DA与AA共存时,由该修饰电极检测的二者氧化峰电位差达184 mV,故可同时测定DA和AA,并有效消除其它组分对DA测定的干扰,已用于实际样品中DA和AA含量的测定,结果令人满意.     

Keggin型磷钨酸/2-氨基吡啶聚合膜修饰电极的电化学性质及对维生素B2的电催化

制备了Keggin型磷钨酸/2-氨基吡啶电聚合复合膜修饰电极,研究了该复合膜修饰电极的电化学性质。结果表明,在BR缓冲溶液中,该复合膜修饰电极显示出3对氧化还原峰,对应于表面电沉积的磷钨酸的电化学作用,其电化学行为受表面吸附控制。该电极对维生素B2（VB2）具有良好的电催化作用,根据VB2的电化学行为,推断出了可能的电极反应机理,计算出VB2在该电极上的电荷转移系数为0.357,电荷转移速率常数为0.042 s-1,推断其在该电极上的行为为准可逆过程。在2.4×10-6~1.0×10-4 mol/L和1.0×10-4~5.5×10-4 mol/L 范围内峰电流与VB2浓度呈良好的线性关系,其检出限为1.4×10-6 mol/L。该电极显示出良好的稳定性和重现性,用于复合维生素药片中VB2含量的测定,结果满意。     

对硫磷在单壁碳纳米管/金-四氧化三铁纳米粒子复合材料修饰电极上的电化学响应及其测定

制备了单壁碳纳米管/金-四氧化三铁纳米粒子复合材料修饰玻碳电极,用循环伏安法研究了对硫磷在该电极上的电化学行为。该电极对对硫磷具有较好的富集和催化特性,在优化条件下,对硫磷的浓度与其峰电流在2.0×10-9～1.0×10-6 mol/L范围内呈线性关系,其检出限为1.0×10-9 mol/L。对1.0×10-7 mol/L的对硫磷溶液平行测定9次的RSD为3.9%(n=9)。用该电极对不同蔬菜样品中的对硫磷进行测定,平均回收率在96.0%～105.5%之间,相对标准偏差在3.3%～3.9%之间。     

Amperometric determination of glutathione and cysteine on a Pd-IrO(2) modified electrode with high performance liquid chromatography in rat brain microdialysate

A Pd/IrO(2) co-electrodeposited glassy carbon electrode was prepared and the electrochemical behavior of glutathione (GSH) at this chemically modified electrode (CME) has been studied by cyclic voltammetry (CV). The results indicated that the modified electrode efficiently exhibited electrocatalytic oxidation for GSH with relatively high sensitivity, stability, and long-life. Coupled with high-performance liquid chromatography (HPLC), the Pd/IrO(2) modified electrode was utilized for the electrochemical detection (ECD) of the thiocompounds, glutathione and cysteine (Cys). The peak currents were linear with the substance concentrations in the range of 1.0 x 10(-5) mol L(-1) to 8.0 x 10(-4) mol L(-1) for GSH and 4.0 x 10(-6) mol L(-1) to 2.0 x 10(-4) mol L(-1) for Cys. The detection limits were 2.0 x 10(-6) mol L(-1) for GSH and 5.0 x 10(-7) mol L(-1) for Cys with S/N of 3. The method has been successfully applied to assess the contents of GSH and Cys in rat brain microdialysates.     

葡萄糖在亚硝基五氰合铁酸铁修饰碳糊电极上的电化学行为研究

采用亚硝基五氰合铁酸铁(FePCNF)粉末与碳粉质量比为2∶3混合,制备了FePCNF修饰碳糊电极.研究了FePCNF修饰碳糊电极在KNO3溶液中的电化学行为和扫速、pH值及不同支持电解质的影响.该电极可用于催化氧化检测葡萄糖.实验表明:FePCNF修饰碳糊电极在0.5 mol/L KNO3溶液中有一对灵敏的氧化还原峰,峰电流与扫速呈线性关系.氧化峰电流与葡萄糖的浓度在2.0×10-6～2.4×10-5 mol/L之间有良好的线性关系(r=0.9934),检出限为6.3×10-7 mol/L.该电极具有良好的稳定性和重现性,适合于微量葡萄糖的检测.     

番红花红聚合膜修饰电极及其应用

研究了番红花红(SFR)在玻碳电极表面聚合过程及聚合条件。SFR聚合膜对于肾上腺素(EP)的氧化能够起到明显的电催化作用。分别利用循环伏安法(CV)、差分脉冲法(DPV)、计时电流法研究了EP在pH7.4的磷酸缓冲溶液中的线性关系,发现其浓度分别在2.0×10-6～9.0×10-6mol/L、1.0×10-5～1.0×10-3mol/L(CV),2.0×10-5～4.0×10-4mol/L(DPV),2.0×10-6～5.0×10-6mol/L(计时电流法)范围内呈良好的线性关系,该电极已用于实际样品测定。     

Electrochemical Behavior of 6-Mercapto-Purine at Hanging Copper Amalgam Dropping Electrode and Its Trace Determination by Differential Pulse Adsorption Cathodic Stripping Voltammetry

Abstract

The electrochemical behavior of 6-MP was studied by cyclic voltammetry at a hanging copper amalgam dropping electrode (HCADE). It was found that 6-MP could form a complex with the Cu(II) stripped from the HCADE, showing a new peak at ?0.19V in the medium of 0.1mol/L LiClO₄-0.5mol/L HClO₄ solution. The mechanism of the reaction was proposed. This new peak was sensitive and could be used for the determination of trace 6-MP by differential pulse adsorption cathodic stripping voltammetry (DPAdCSV). The linear range was from 3.6×10^?10 to 5.3×10^?6 mol/L, and the detection limit was about 1.2×10^?10 mol/L (S/N=3). The method was also successfully applied to the determination of 6-MP in pharmaceutical tablets.     

过氧化氢-巯嘌呤氧化还原反应的研究及荧光分析应用

研究了过氧化氢氧化巯嘌呤的反应条件及产物的荧光特性 ,提出了高灵敏荧光光度法测定巯嘌呤含量的新方法。在碱性介质和沸水浴加热条件下 ,过氧化氢能将巯嘌呤定量转化为 6-嘌呤磺酸钠 ,其体系的荧光强度与巯嘌呤浓度在6.0× 1 0 -8～ 1 .0× 1 0 -5mol/L范围内呈线性关系 ,检出限为 2 .4× 1 0 -8mol/L。该法已用于片剂中的巯嘌呤含量的测定。     

多壁纳米管修饰电极电催化3,4-二羟基苯甲酸研究

应用循环伏安(CV)和方波伏安(SWV)法研究3,4-二羟基苯甲酸(DHBA)在多壁碳纳米管修饰的玻碳电极上的电化学行为.实验表明:该修饰电极对DHBA有较强的电催化作用.由方波伏安法测定的氧化峰电流在DHBA浓度为4.0×10-6~1.0×10-4mol/L和2.0×10-4~8.0×10-4mol/L范围内分段呈线性变化关系;相关系数各为0.9995和0.9992,检测限1.0×10-6mol/L.     

单扫示波极谱法测定氧氟沙星

在 0 .1 5mol/L HAc- Na Ac( p H 3.64)中 ,采用单扫示波极谱法测定氧氟沙星 ,得到一良好的还原峰 ,峰电位 Ep=- 1 .45V( vs.SCE)。峰电流 IP与氧氟沙星的浓度在 3.0× 1 0 - 7～ 6.2× 1 0 - 6 mol/L范围内呈线性关系 ,相关系数 r=0 .9983,检出限为 7.0× 1 0 - 8mol/L。此法已用于片剂的测定。用线性扫描和循环伏安法研究了体系性质 ,结果表明 ,氧氟沙星的电极过程为具有吸附性的不可逆过程。     

多菌灵在羧甲基纤维素钠/蒙脱土修饰电极上的电化学行为及测定

制备了羧甲基纤维素钠/蒙脱土修饰电极,研究了多菌灵在该修饰电极上的电化学行为并用方波伏安法对其进行测定。实验结果表明,多菌灵在修饰电极上出现了一个不可逆氧化峰,该氧化过程受扩散控制,多菌灵浓度在2.0×10-6～6.0×10-5mol/L范围内,方波伏安法的氧化峰电流与多菌灵浓度呈现良好的线性关系,检出限为8.5×10-7mol/L,可用于检测溶液中多菌灵含量。