单壁碳纳米管-氧化石墨烯复合修饰电极测定邻苯二酚

制备了用于测定邻苯二酚的单壁碳纳米管-氧化石墨烯复合修饰玻碳电极.用循环伏安法研究了邻苯二酚在该电极上的电化学行为.结果表明,该修饰电极对邻苯二酚具有良好的电催化性能.在最佳实验条件下,采用差分脉冲伏安法对邻苯二酚进行了测定,其氧化峰电流与邻苯二酚浓度在2×10~(-6)~1×10~(-4) mol/L范围内呈线性关系,相关系数为0.996 2,检出限为4×10~(-7) mol/L.该电极具有良好的重现性,用于模拟废水中邻苯二酚的测定结果令人满意.     

邻苯二酚和对苯二酚在电活化玻碳电极上的电化学行为及同时测定

制备了电活化的玻碳电极,利用循环伏安法研究了邻苯二酚和对苯二酚在该电极上的电化学行为,结果表明该电极对两者的氧化还原具有很好的电催化能力。在0.1 mol/L PBS(pH 7.0)中,采用示差脉冲伏安法对对苯二酚和邻苯二酚分别测定和同时测定,对苯二酚和邻苯二酚的氧化峰电流与其浓度分别在3.0×10-7～1.2×10-5 mol/L和1.0×10-7～1.2×10-5 mol/L范围内呈良好的线性关系,检测限分别为1.0×10-7和6.34×10-8mol/L(S/N=3)。该法已用于模拟废水样中对苯二酚和邻苯二酚的测定。     

银掺杂聚L-甲硫氨酸修饰电极同时测定对苯二酚和邻苯二酚

用循环伏安法制备了银掺杂聚L-甲硫氨酸修饰玻碳电极,研究了对苯二酚和邻苯二酚在该修饰电极上的电化学行为,建立了同时测定对苯二酚和邻苯二酚的新方法.研究发现,在pH=5.0的磷酸盐缓冲溶液中,扫速为100 mV/s时,对苯二酚和邻苯二酚在银掺杂聚L-甲硫氨酸修饰玻碳电极上均出现1对氧化还原峰,峰电位分别为:Epa=0.228 V、Epc =0.162 V和Epa=0.347 V、Epc =0.287 V,二者的氧化峰电位差达119 mV,还原峰差达125 mV.在最佳的条件下,用差分脉冲伏安法同时测定邻苯二酚和对苯二酚的线性范围为3.00 ×10-6～1.00 ×10-4mol/L,检出限为8.0×10-7 mol/L(对苯二酚)和5.0×10-7 mol/L(邻苯二酚).此法用于废水样中对苯二酚和邻苯二酚的测定,获得满意结果.     

电化学分析法测定中药中虎杖苷

建立了虎杖苷在碳纳米管修饰玻碳(CNT/GC)电极上的电化学检测方法。在0.2 mol/L HCl溶液中,用方波溶出伏安法研究了虎杖苷在CNT/GC电极上的电化学行为。虎杖苷在+0.83V(vs.Ag/AgCl)电位处产生一个阳极氧化峰,峰电流与虎杖苷的浓度在7.0×10-7～4.0×10-5mol/L范围内呈良好的线性关系,最低检测限达4.57×10-7mol/L。方法可用于生药材和中成药中虎杖苷的测定。     

聚苯胺-石墨烯修饰玻碳电极同时测定邻苯二酚和对苯二酚

本文制备了聚苯胺-石墨烯修饰玻碳电极,并用循环伏安(CV)法和微分脉冲伏安(DPV)法研究了邻苯二酚(CC)和对苯二酚(HQ)在该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,HQ和CC在聚苯胺-石墨烯修饰电极上的氧化峰电流显著提高,氧化峰电位相差104.8mV,实现了CC和HQ的选择性测定。DPV法同时测定二酚时,HQ和CC分别在1.0×10-6~8.0×10-4 mol/L浓度范围内与其峰电流呈良好的线性关系,相关系数R分别为0.998、0.997,检出限(S/N=3)分别为1.0×10-7、8.0×10-8mol/L。将该方法用于模拟水样分析,回收率为95.3%~103.5%。     

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。     

聚多巴胺-还原氧化石墨烯修饰电极同时测定邻苯二酚和对苯二酚

制备了聚多巴胺-还原氧化石墨烯修饰玻碳电极(PDA-rGO/GCE),以此修饰电极作为工作电极,采用循环伏安法(CV)对邻苯二酚(CC)和对苯二酚(HQ)的电化学行为进行了研究。结果表明CC和HQ在该修饰电极上的峰电流与氧化石墨烯修饰电极相比有了明显增高,并且它们的氧化峰电位差和还原峰电位差均超过110 mV,证明该修饰电极用于两种酚的同时检测是可行的。在优化实验条件下,采用微分脉冲伏安法(DPV)对CC和HQ同时进行检测,CC和HQ的峰电流与其浓度均在1.0×10~(-6)～4.0×10~(-3) mol/L范围内呈良好的线性关系,检出限(S/N=3)分别为2.0×10~(-7) mol/L和3.6×10~(-7) mol/L。以所制备的修饰电极对自来水水样和湖水水样进行了加标回收检测,回收率在97.6%～100.6%范围内。     

一种基于乙炔黑/壳聚糖膜修饰电极的对氨基酚传感研究

制备了一种乙炔黑/壳聚糖薄膜修饰的玻碳电极,用循环伏安法详细研究了对氨基酚在该修饰电极上的电化学行为.结果表明: 对氨基酚在此膜修饰电极上呈现出一对可逆的氧化还原峰.相对于裸玻碳电极,该氧化还原峰的峰电流明显提高,峰电位差减小,可逆性变好,表明乙炔黑/壳聚糖薄膜电极对对氨基酚的电化学氧化具有良好的催化作用.对氨基酚的氧化峰电流与其浓度在1.0×10-7～2.0×10-6 mol/L和2 0×10-6～5.0×10-4 mol/L范围内均呈良好的线性关系; 检出限为5.0×10-8 mol/L(S/N=3).应用此修饰电极测定实际水样,结果较满意.     

一种基于碳纳米管的色氨酸传感器

研究了色氨酸(tryptophan即Trp)在多壁碳纳米管修饰玻碳电极(MWNTs/GC)上的电化学行为。MWNTs/GC电极对Trp具有良好的电催化作用,相对于GC电极,Trp在MWNTs/GC上峰电位负移128 mV,峰电流约为GC电极上氧化峰电流的31倍。在1.0 mol/L H2SO4中清洗能更新电极表面,消除产物吸附带来的影响。MWNTs/GC电极在含1.0×10-4mol/L Trp的缓冲溶液中闭路富集2 min时电流达到稳定值。研究了不同pH值影响的结果表明,参与电极反应的质子数和电子数相等。在pH=2.2时,Trp的氧化电流最大。利用LSV研究了电流与扫描速率的关系,结果表明,Trp在修饰电极上的氧化过程为扩散控制过程。在环境温度低于45℃时,随着温度增加,氧化电流逐渐增大。温度在16~35℃范围内,传感器的响应电流与温度成线性关系,温度系数为0.695μA/℃,说明此传感器在实测过程中因温度波动带来的测量误差很小。利用LSV研究了氧化峰电流与Trp的浓度关系的结果显示,峰电流与Trp的浓度在1.00×10-6~1.00×10-4mol/L范围内呈良好线性关系,检出限为1.82×10-7mol/L(S/N=3)。该电极具有良好的灵敏度、选择性和稳定性,放置7 d后,碳纳米管的峰电流仍能达到最初电流的98%。     

聚L-半胱氨酸/多壁碳纳米管复合修饰电极同时测定邻苯二酚和对苯二酚

将羧基化多壁碳纳米管分散在L-半胱氨酸溶液中并滴涂在玻碳电极表面.将上述电极在pH 6.9的B-R缓冲溶液中,于-1.0～2.5 V的电位范围内进行电聚合,制备了聚L-半胱氨酸/多壁碳纳米管复合修饰电极(Pol-L-Cys/MWCNTs/GCE).研究发现,邻苯二酚和对苯二酚在聚L-半胱氨酸/多壁碳纳米管复合修饰电极上分别出现了一对氧化还原峰,且两者的氧化峰电位差达101 mV,提出了用微分脉冲伏安法同时测定邻苯二酚和对苯二酚的方法.氧化峰电流与邻苯二酚和对苯二酚的浓度在1.0×10-5～1.0×10-3mol·L-1呈线性关系,检出限(3S/N)均达1.0×10-5mol·L-1.修饰电极用于模拟样品中邻苯二酚和对苯二酚的测定,回收率在82.0%～107.0%之间.     

Simultaneous Determination of Hydroquinone and Catechol at a Glassy Carbon Electrode Modified with Multiwall Carbon Nanotubes

A simply and high selectively electrochemical method for simultaneous determination of hydroquinone and catechol has been developed at a glassy carbon electrode modified with multiwall carbon nanotubes (MWNT). It was found that the oxidation peak separation of hydroquinone and catechol and the oxidation currents of hydroquinone and catechol greatly increase at MWNT modified electrode in 0.20 M acetate buffer solution (pH 4.5). The oxidation peaks of hydroquinone and catechol merge into a large peak of 302 mV (vs. Ag/AgCl, 3 M NaCl) at bare glassy carbon electrode. The two corresponding well‐defined oxidation peaks of hydroquinone in the presence of catechol at MWNT modified electrode occur at 264 mV and 162 mV, respectively. Under the optimized condition, the oxidation peak current of hydroquinone is linear over a range from 1.0×10^?6 M to 1.0×10^?4 M hydroquinone in the presence of 1.0×10^?4 M catechol with the detection limit of 7.5×10^?7 M and the oxidation peak current of catechol is linear over a range from 6.0×10^?7 M to 1.0×10^?4 M catechol in the presence of 1.0×10^?4 M hydroquinone with the detection limit of 2.0×10^?7 M. The proposed method has been applied to simultaneous determination of hydroquinone and catechol in a water sample with simplicity and high selectivity.     

Electrocatalytic activity and simultaneous determination of catechol and hydroquinone at mesoporous platinum electrode

The electrochemical oxidation of catechol and hydroquinone was investigated using cyclic and differential pulse voltammetries at nanostructured mesoporous platinum film electrochemically deposited from the hexagonal liquid crystalline template of C₁₆EO₈ surfactant. The mesoporous platinum electrode has shown an excellent electrocatalytic activity and reversibility towards the oxidation of catechol and hydroquinone redox isomers in 1.0 M HClO₄. The oxidation and reduction peak separation (ΔE) has been decreased from 485 to 55 mV for hydroquinone and from 430 to 75 mV vs. SCE for catechol at polished polycrystalline and mesoporous platinum electrodes, respectively. The differential pulse voltammograms in a mixture solution of catechol and hydroquinone have shown that the oxidation peaks became well resolved and are separated by about 100 mV, although the bare electrode gave a single broad oxidation peak. Moreover, the oxidation current of hydroquinone and catechol has been enhanced by a factor of two and four times, respectively, at mesoporous platinum electrode. Using differential pulse voltammetry, a highly selective and simultaneous determination of hydroquinone and catechol has been explored at mesoporous platinum electrode.     

聚血红素修饰电极对儿茶酚类化合物和抗坏血酸氧化的电催化作用研究

电催化是化学修饰电极研究的中心课题之一,血红素是一种重要的铁卟啉化合物,其中的铁原子能够以两种价态存在．我们采用循环伏安法将血红素修饰于电极表面,得到了氧化还原体（ｒｅｄｏｘ）型化学修饰电极,并用于儿茶酚类化合物和抗坏血酸的电催化氧化研究．采用伏安法...     

pMB/MWNTs/GC电极对水体中苯二酚异构体的同时测定

通过在多壁碳纳米管修饰玻碳电极上电聚合亚甲基蓝,制备了聚亚甲基蓝/碳纳米管/玻碳电极(pMB/MWNTs/GC)。用循环伏安法研究了3种苯二酚异构体在该电极上的电化学行为,结果表明,在pH7.0的磷酸盐缓冲溶液中,该修饰电极对苯二酚异构体的氧化表现出优异的电催化性能和选择性,对苯二酚、邻苯二酚和间苯二酚的氧化峰分别为0.104、0.203、0.609 V(vs.SCE),峰电位差值分别为99、406 mV。基于苯二酚异构体在pMB/MWNTs/GC修饰电极上的伏安行为,建立了苯二酚3种异构体同时分析的新方法。考察了各影响因素对测定的影响,最优实验条件下,在5.0×10-6~1.5×10-4mol.L-1范围内,3种苯二酚异构体的阳极峰电流与其浓度存在线性关系,检出限均为1.0×10-6mol.L-1。将该法用于水体及冲洗废液中苯二酚异构体含量的测定,结果满意。     

Electrochemical oxidation of catechol at poly(indole-5-carboxylic acid) electrode

In this work we examined the electrochemical properties of poly(indole-5-carboxylic acid), PIn₅COOH. The polymer was produced by electrochemical polymerisation using cyclic voltammetry (CV). It was shown that PIn₅COOH is electroactive in aqueous solutions showing two redox processes in acidic solution and one redox process in solutions with pH > 4. The oxidation of catechol (CT) on Pt/In₅COOH modified electrodes was investigated by cyclic voltammetry (CV) and rotating disc electrode (RDE) voltammetry. It was established that CT was oxidised only after the oxidation of polymer film was initiated and that polymer significantly enhanced the oxidation and reduction peak currents in comparison with bare Pt electrode. The variation of peak currents (i _pa, i _pc) as a function of CT concentration was found to be linear up to 6 mM. Experiments with a rotating disk electrode show that the oxidation reaction of catechol occures not only at the polymer/electrolyte interface but also in the polymer film.     

钯/碳纳米纤维复合材料修饰电极同时检测邻苯二酚和对苯二酚

利用电纺丝技术制得钯/碳纳米纤维复合材料(Pd/CNFs),并将其用于修饰玻碳电极Pd/CNF-GCE/CME.Pd/CNF-GCE/CME对邻苯二酚和对苯二酚的氧化还原反应具有较高的电催化活性,显著提高了二者电化学反应的可逆性.考察了支持电解质的酸度对邻苯二酚和对苯二酚电化学响应的影响,选用0.1 mol/L PBS(pH 8.0)作为支持电解质.用微分脉冲伏安(DPV)法对邻苯二酚和对苯二酚进行选择性检测:当混合溶液中存在50 μmol/L对苯二酚时,邻苯二酚的氧化峰电流与其浓度在1～90 μmol/L范围内呈线性关系,检出限为0.3 μmol/L(S/N=3);当存在50 μmol/L邻苯二酚时,对苯二酚的氧化峰电流与其浓度在2～100 μmol/L范围内呈线性关系,检出限为1.0 μmol/L.另外,此修饰电极具有较好的重现性和较强的抗干扰能力.将此修饰电极用于模拟水样中邻苯二酚和对苯二酚的测定,结果令人满意.     

Simultaneous Determination of Dihydroxybenzene Isomers Using Preanodized Inlaying Ultrathin Carbon Paste Electrode

In this paper, we described a rapid, sensitive and selective method for simultaneous voltammetric determination of dihydroxybenzene isomers with a preanodized inlaying ultrathin carbon paste electrode (PAIUCPE). Scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry were employed to characterize the configuration and electrochemical properties of the electrode. The resulting PAIUCPE exhibited excellent recognition ability towards dihydroxybenzene isomers. Three well‐defined oxidation peaks of catechol (CC), resorcinol (RC) and hydroquinone (HQ) can be identified entirely at the electrode. The oxidation peak potential difference between HQ and CC was 120 mV, CC and RC 430 mV, respectively. The peak currents increased linearly with increasing the concentration of dihydroxybenzene isomers. The proposed electrode can be applied to simultaneous determination of dihydroxybenzene isomers without previous chemical or physical separations.     

邻苯二酚和对苯二酚在钴氢氧化物膜修饰玻碳电极上的选择性测定

通过镀膜/循环伏安法制备了钴氢氧化物膜修饰的玻碳电极。该修饰电极对邻苯二酚(CA)和对苯二酚(HQ)具有较强的电催化活性。考察了支持电解质酸度对邻苯二酚和对苯二酚电化学响应的影响,选用0.1 mol/LPBS(pH 10.0)作为支持电解质。利用差示脉冲伏安法(DPV)对邻苯二酚和对苯二酚进行选择性检测,当两者浓度同时改变时,邻苯二酚和对苯二酚在6～100μmol/L范围内氧化峰电流与其浓度呈良好的线性关系,检出限分别为2×10–7,5×10–7mol/L(S/N=3)。钴氢氧化物膜电极具有较好的稳定性、重现性及较强的抗干扰能力,将此修饰电极应用于模拟水样中邻苯二酚和对苯二酚的测定,回收率为95.4%～100.4%。     

Sensitive simultaneous determination of catechol and hydroquinone using a gold electrode modified with carbon nanofibers and gold nanoparticles

A highly sensitive electrochemical sensor for the simultaneous determination of catechol (CC) and hydroquinone (HQ) was fabricated by electrodeposition of gold nanoparticles onto carbon nanofiber film pre-cast on an Au electrode. Both CC and HQ cause a pair of quasi-reversible and well-defined redox peaks at the modified electrode in pH?7.0 solution. Simultaneously, the oxidation peak potentials of CC and HQ become separated by 112?mV. When simultaneously changing the concentrations of both CC and HQ, the response is linear between 9.0???M and 1.50?mM. In the presence of 0.15?mM of the respective isomer, the electrode gives a linear response in the range from 5.0 to 350???M, and from 9.0 to 500???M for CC and HQ, respectively, and detection limits are 0.36 and 0.86???M. The method was successfully examined for real sample analysis with high selectivity and sensitivity.