碳糊电极吸附溶出伏安法测定游离钙

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。     

碳糊电极阴极吸附伏安法测定橙皮甙

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.     

Nafion修饰电极阴极溶出伏安法测定痕量钛

本文采用Ｎａｆｉｏｎ修饰玻碳电极阴极溶出伏安法测定痕量钛。研究了Ｎａｆｉｏｎ膜的有关特性和测定的佳化条件。当富集时间为１ｍｉｎ时，Ｔｉ（Ⅳ）浓度与峰电流在１．０～５０ｎｇ／ｍｌ范围内呈线性关系。本法应用于铝合金和白泥标样中钛的测定，结果满意。     

阴极溶出伏安法测定异烟肼的研究

报道了吸附阴极溶出伏安法测定异烟肼。探讨了电极反应机理。在０．０１ｍｇｏｌ／Ｌ硼砂底液中，峰电位为－１．４０Ｖ。峰电流与异烟肼浓度在４．０＊１０＾－７－１．５＊１０＾－５ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系为０．９９１３。该方法用于异烟肼片剂的测定，获得满意结果。     

槲皮素化学修饰碳糊电极吸附溶出伏安法测定痕量铅

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。     

辛可宁修饰碳糊电极的应用研究——铋的阳极溶出伏安法测定

报道了利用辛可宁修饰碳糊电极测定铋的方法,在1mol/LH2SO4溶液中,通过在－1.00V电位下富集Bi3＋后,在－0.20～＋0.15V电位范围内作阳极溶出伏安法测定。在－0.022V处有一灵敏的氧化峰,峰电流与Bi     

碳糊电极阳极溶出法测定单宁酸的研究

用碳糊电极阳极溶出法研究了单宁酸的测定方法。实验表明,在1.0 mol/LHCl介质中,富集120 s,单宁酸在0.65 V(vs.SCE)处出现阳极溶出峰,在5.0×10-7~6.0×10-5mol/L范围内,其峰电流的大小与单宁酸的浓度呈线性关系,相关系数为0.9991,检出限为1.0×10-7mol/L。该法灵敏度较高,操作简便,可用于啤酒中单宁酸的测定,平均回收率为99.8%。     

用混合粘合剂修饰的碳糊电极测定诺氟沙星

在pH10.50的磷酸盐缓冲溶液中 ,当含有0.8mmol/L的NH4Cl,8mg/L的SLS(十二烷基磺酸钠)时 ,诺氟沙星在由69.1% (w)的石墨粉、24.5 % (w)的液体石蜡和6.4 % (w)的甘油组成的混合粘合剂碳糊电极上产生一灵敏的阴极溶出还原峰 ,峰电位为 -1.61V ;峰电流与诺氟沙星浓度在8.0×10 -9～4.0×10 -7mol/L范围内呈良好的线性关系 ,相关系数为r=0.9949 ,检出限为3.0×10-9 mol/L ;该法用于测定诺氟沙星胶囊含量 ,结果令人满意     

靛红在碳糊电极上的阴极吸附伏安法研究

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。     

Voltammetric Determination of Selected Aminoquinolines Using Carbon Paste Electrode

Optimum conditions have been found for voltammetric determination of mutagenic 5‐aminoquinoline, 6‐aminoquinoline and 3‐aminoquinoline by differential pulse voltammetry and adsorptive stripping differential pulse voltammetry on carbon paste electrode. The lowest limits of determination were found for adsorptive stripping differential pulse voltammetry in 0.1 mol dm^?3 H₃PO₄ (5×10^?7 mol dm^?3 , 1×10^?7 mol dm^?3, and 1×10^?7 mol dm^?3 for 5‐aminoquinoline, 6‐aminoquinoline and 3‐aminoquinoline, respectively). The possibility to determine mixtures of 8‐aminoquinoline with 3‐aminoquinoline or 5‐aminoquinoline or 6‐aminoquinoline, and mixtures of 5‐aminoquinoline with 3‐aminoquinoline or 6‐aminoquinoline by differential pulse voltammetry was verified. Binary mixtures of 8‐aminoquinoline with 3‐aminoquinoline or 6‐aminoquinoline, and of 3‐aminoquinoline with 5‐aminoquinoline could be successfully analyzed.     

Square Wave Adsorptive Stripping Voltammetric Determination of Cyromazine Insecticide with Multi-Walled Carbon Nanotube Paste Electrode

The electrochemical behavior of cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6 triamine) insecticide has been studied at newly prepared multi-wall carbon nanotubes paste electrodes using square wave stripping voltammetry. The cyromazine was accumulated at 0.0 mV [vs. Ag/AgCl (3 M NaCl)] and a well-defined anodic peak obtained at +1110 mV in 0.1 M H₂SO₄. The cyclic voltammetric measurements showed an irreversible nature of oxidation wave in the range of scan rates comprised between 500 and 4000 mV s^?1. The calibration curve obtained from square wave stripping voltammetry was linear in the range 0.41 to 83.30 µg/mL with a detection limit of 0.12 µg/mL. The method was applied to the direct determination of cyromazine in natural water samples. Recoveries calculated for river and tap water samples spiked with 10.0 µg/mL level were 101.5 ± 1.9% and 100.6 ± 2.3% at 95% confidence level, respectively. The method was extended to the determination of cyromazine in agrochemical formulation Trigard® with a recovery of 100.49% and accuracy was in agreement with that obtained by HPLC comparison method. Influences of some interfering ions and pesticides were also investigated.     

Carbon Paste Electrode Modified by Surfactant for Anodic Stripping Voltammetric Determination of Sulphadiazine

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Carbon Paste Electrode Plated with Lead Film. Voltammetric Characteristics and Application in Adsorptive Stripping Voltammetry

A lead film plated in situ at a carbon paste support was tested as a novel, potential electrode for adsorptive stripping voltammetric determination of cobalt traces in an ammonia buffer solution. To show the practical applicability of the new electrode, a catalytic adsorptive Co system in a supporting electrolyte containing 0.1 M ammonia buffer, 5×10^?4 M nioxime and 0.25 M nitrite was selected and investigated as a model solution. Pb and Co ions were simultaneously accumulated in situ on the electrode surface: Pb ions electrochemically at ?1.3 V) and then at ?0.75 V, at which potential the Co(II)‐nioximate complex was also pre‐concentrated via adsorption. Instrumental parameters, such as the time of nucleation and formation of Pb film deposits, the time of accumulation of the Co‐nioxime complex at the PbF/CPE, and the procedures of electrode regeneration, were optimized to obtain good reproducibility and sensitivity of the Co response. The optimized procedure yields favorable and highly stable stripping responses with good precision (RSD=3% for a 5×10^?8 M Co) and good linearity (up to 5×10^?7 M, coefficient of determination, R=0.996). The detection limit was 4×10^?10 M Co (0.023 μg L^?1) for an accumulation time of 120 s. The method enables the determination of Co in the presence of high excesses of Ni or Zn. The voltammetric data were correlated with the structural characterization by scanning electron microscopy (SEM) and X‐ray fluorescence spectroscopy (XRF).