共查询到20条相似文献,搜索用时 0 毫秒
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Margarita Stoytcheva Roumen Zlatev Zdravka Velkova Velizar Gochev Alan Ayala Gisela Montero Benjamín Valdez 《Electroanalysis》2021,33(3):695-704
A laponite modified carbon paste electrode was prepared, characterized and applied for the 2,4-dichlorophenol (2,4-DCP) voltammetric determination. It takes advantage of the ability of laponite to adsorb phenols, as well as of its availability and very low cost. Kinetic and equilibrium data for 2,4-DCP adsorption by laponite in aqueous dispersions demonstrated that the adsorption process obeyed a pseudo first order kinetic model and was consistent with the formation of adsorbed multilayers on a surface with heterogeneous pore distribution. The composite paste electrode exhibited a heterogeneous surface with 65 % increased surface area and 27 % enhanced catalytic activity compared to the unmodified one. The adsorptive stripping voltammetric determination of 2,4-DCP at an electrode with an optimized graphite:laponite ratio of 55 : 15 w% using a 3 min accumulation time at pH 5.5 was found to be suitable for its quantification in the linear concentration range extended up to 50 μmol L−1 with a sensitivity of 0.56 μA L μmol−1 and a LOD of 0.2 μmol L−1 (S/N=3).The 2,4-DCP electrochemical response was not affected by the presence of some structurally similar phenols, like catechol and p-nitrophenol, while resorcinol, 2-chlorophenol, and 4-chlorophenol presented interferences. The results were validated by 2,4-DCP determination in spiked tap water. 相似文献
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槲皮素化学修饰碳糊电极吸附溶出伏安法测定痕量铅 总被引:14,自引:0,他引:14
建立了用槲皮素修饰碳糊电极测定痕量铅的新方法 ,在 0 .1 0mol L甲酸盐缓冲液 (pH 4.3 )中 ,于 -0 .1 0V(vs.SCE)搅拌富集 ,再在 -0 .70V静止还原 40s后 ,阳极化扫描 ,于 -0 .42V左右获得一灵敏的铅阳极溶出峰。在最佳条件下 ,富集不同时间 ,其二次导数峰电流与Pb2 + 在 1 .0× 1 0 - 8~ 8.0× 1 0 - 7mol L和 2 .0× 1 0 - 9~ 6.0× 1 0 - 8mol L两个范围内呈线性关系 ,检出限为 8.0× 1 0 - 1 0 mol L(S N =3 )。同时初步探讨了电极反应机理。 相似文献
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碳糊电极吸附溶出伏安法测定游离钙 总被引:8,自引:0,他引:8
基于Ca(Ⅱ)-茜素红S(ARS)络合物在碳糊电极上的还原波,建立了吸附溶出伏安测定游离钙的新方法。在1.5×10-2mol/LKOH-2.0×10-5mol/LARS介质中,Ca(Ⅱ)-ARS络合物在碳糊电极上于-0.89V处产生一吸附还原波。当富集电位为.0.1V,富集时间90s,扫描速度为100mV/s时,该络合物单扫描阴极溶出峰的二阶导数峰电流与游离钙离子浓度在3.0×10-8~2.0×10-6mol/L范围内呈线性关系;检出限为9.4×10-9mol/L。在0.2mol/LHCl中清洗2min,该电极重现性良好。该方法可用于血清、牛奶和自来水中游离钙的测定。 相似文献
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Electrochemical reduction and determination of montelukast (MKS) was studied in methanol – 0.1 M HCl solution (1 : 1, v/v) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at chitosan modified carbon paste electrode. The linear range was 1.70×10?7–1.83×10?5 M for DPV analysis. Limit of detection (LOD) and limit of quantification (LOQ) were 5.32×10?8 M and 1.61×10?7 M, respectively. The developed method was successfully applied to the determination of MKS in tablets and spiked human plasma. The results obtained were in good agreement with those obtained using a reported spectrofluorimetric technique. 相似文献
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邻苯三酚红修饰碳糊电极吸附伏安法测定痕量铋 总被引:3,自引:0,他引:3
报道了采用邻苯三酚红修饰碳糊电极测定痕量铋的方法。在0.30mol/L的HCl溶液中,于-0.10V搅拌富集3min,然后在-0.35V静止还原60s,再进行阳极化扫描,在-0.10V左右获得灵敏的铋溶出峰,二次导数民流与铋浓度在1.0*10^-9-6.0*10^-7mol/L范围内呈线性关系,同限为5*10^-10mol/L。对电极反应机理进行了讨论。 相似文献
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碳糊电极阳极吸附伏安法测定环丙沙星 总被引:6,自引:0,他引:6
报道了用碳糊电极阳极吸附伏安法测定环丙沙星的新方法.在 0. 40mol/L的NH4Ac HAc(pH4. 30)缓冲液中,使用JP 303极谱分析仪,环丙沙星在碳糊电极 (CPE)上有一灵敏的吸附伏安氧化峰,峰电位为1. 12V(vs.SCE).该氧化峰的二阶导数峰电流与环丙沙星的浓度在 8. 0×10-9 ~8. 0×10-7 mol/L(富集 90s)范围内成良好的线性关系,相关系数为 0. 998 8,检出限为 4. 0×10-9 mol/L(S/N=3,富集 110s).探讨了环丙沙星在碳糊电极上的伏安性质和电极反应机理,并且成功应用于人体尿样中环丙沙星含量的测定.加入回收实验,回收率在95. 5%至 103. 9%之间. 相似文献
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在0.4mol/L的NH4Cl-NH3(pH9.0)缓冲液中,使用JP-303极谱分析仪,橙皮甙在碳糊电极(CPE)上有一灵敏的吸附伏安还原峰,峰电位为-1.2V(vs.SCE).该还原峰的二阶导数峰电流与橙皮甙的浓度在2.0×10-8~1.0×10-6mol/L(富集90s)范围内成良好的线性关系,相关系数为0.9963,检出限为1.0×10-8mol/L(S/N=3,富集110s).探讨了橙皮甙在碳糊电极上的伏安性质和电极反应机理,并且成功应用于中草药桔皮中橙皮甙含量的测定. 相似文献
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靛红在碳糊电极上的阴极吸附伏安法研究 总被引:1,自引:0,他引:1
利用极谱分析仪,在0.40 mol/L的HAc-NaAc(pH 6.0)缓冲液中,发现靛红在碳糊电极(CPE)上有一灵敏的吸附伏安还原峰,峰电位为-0.44 V(vs.SCE)。该还原峰的二阶导数峰电流与靛红的浓度在4.0×10-8~1.0×10-7mol/L(富集90 s)范围内成良好的线性关系,相关系数为0.9954,检出限为8.0×10-9mol/L(S/N=3,富集110 s)。探讨了靛红在碳糊电极上的伏安性质和电极反应机理,并且成功应用于中草药青黛中靛红含量的测定。 相似文献
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茜素紫修饰碳糊电极阳极溶出伏安法测定痕量锡 总被引:9,自引:0,他引:9
研究了利用茜素紫修饰碳糊电极测定痕量锡的阳极溶出伏安法。在 0 1 5mol/L醋酸盐缓冲溶液 (pH 4 .8)中 ,通过开路富集 ,Sn 和茜素紫形成络合物富集于电极表面 ,然后经过介质交换至 3 0mol/L的盐酸溶液中 ,于 -0 .80V还原后再进行阳极化扫描 ,于 -0 .68V左右获得一灵敏的锡的溶出峰。二次导数峰电流与Sn 浓度在 8.4× 1 0 -9~ 1 .4× 1 0 -6mol/L范围内呈良好的线性关系。检出限达 4×1 0 -9mol/L ,同时对电极反应机理进行了讨论。 相似文献
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Voltammetry using solid electrodes usually suffers from the contamination due to the deposition of the redox products of analytes on the electrode surface. The contamination has resulted in poor reproducibility and overelaborate operation procedures. The use of the chemical catalysis of oxidant on the reduction product of analyte not only can eliminate the contamination of analyte to solid electrodes but also can improve the faradaic response of analyte. This work introduced both the catalysis of oxidant K2S2O8 and the enhancement of surfactant Triton X-100 on the faraday response of amiodarone into an adsorptive stripping voltammetry at a carbon paste electrode for the determination of amiodarone. The method exhibits high sensitivity, good reproducibility and simple operation procedure. In 0.2 mol·L^-1 HOAc-NaOAc buffer (pH=5.3) containing 2.2×10^-2 mol·L^-1 K2S2O8 and 0.002% Triton X-100, the 2.5th-order derivative stripping peak current of the catalytic wave at 0.3 V (vs. Ag/AgCl) is rectilinear to amiodarone concentration in the range of 2.0×10^-10-2.3×10^-8 mol·L^-1 with a detection limit of 1.5×10^-10 mol·L^-1 after accumulation at 0 V for 30 s. 相似文献
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CarbonPasteElectrodeModifiedbySurfactantforAnodicStrippingVoltammetricDeterminationofSulphadiazineZhangZheng-qi;ChenZhan-guan... 相似文献
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碳糊电极阳极吸附伏安法测定诺氟沙星 总被引:1,自引:0,他引:1
报道了用碳糊电极阳极吸附伏安法测定诺氟沙星的方法。在0.40 mol.L-1的NH4OAc-HOAc(pH 4.51)缓冲溶液中,诺氟沙星在碳糊电极(CPE)上有一灵敏的吸附氧化峰,峰电位为1.16 V(vs.SCE)。该氧化峰的二阶导数峰电流与诺氟沙星的浓度在4.0×10-9~4.0×10-7mol.L-1(富集90 s)范围内呈线性关系,相关系数为0.996,检出限为1.0×10-9mol.L-1(S/N=3,富集110 s);应用于人体尿液中诺氟沙星含量的测定,方法的回收率为99.1%~104.0%。文中探讨了诺氟沙星在碳糊电极上的伏安性质和电极反应机理。 相似文献
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A method for the voltammetric determination of vanadium using a carbon paste electrode (CPE) was described. The new procedure is based on the adsorptive accumulation of the V(V)‐alizarin red S(ARS) complex onto the surface of the CPE, followed by the electrochemical reduction of adsorbed species. The optimal experimental conditions include the use of 0.10 mol/L acetate buffer (pH 5.1), 1.0×10?5 mol/L ARS, an accumulation potential of ?0.10 V (versus SCE), an accumulation time of 2 min, a scan rate of 200 mV/s and a second‐order derivative linear scan mode. The reduction peak for the complex appears at ?0.52 V. The peak current is proportional to the concentration of V(V) over the range of 0.10–15.0 μg/L, and the detection limit is 0.04 μg/L for a 2 min adsorption time. The relative standard deviations(n=8) for 2.0 and 0.50 μg/L V(V) are 3.1 and 4.7%, respectively. The proposed method was applied to the determination of vanadium in water samples. 相似文献
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Determination of Carbendazim by Adsorptive Stripping Differential Pulse Voltammetry Employing Glassy Carbon Paste Electrode Modified with Graphene and Amberlite XAD 2 Resin
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Graphene nanosheets (GNS) and amberlite XAD‐2 (XAD2) modified glassy carbon paste electrode (GNS‐XAD2‐GCPE) were fabricated for voltammetric determination of Carbendazim (MBC). GNS was synthesized by Hummer’s method and characterized by SEM, EDAX, and XRD techniques. After optimizing the analytical conditions in 0.4 M citrate buffer (pH 4.0), the peak current was found to be linear in the range of 8.36×10?9 to 4.13×10?6 M (r=0.9986) with detection limit of 3.14×10?9 M (S/N=3) by AdSDPV. The method was validated for the determination of MBC in soil, fruit, blood serum, urine, waste and ground water samples with satisfactory recoveries. 相似文献