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《应用化工》2022,(11):2782-2786
制备了富勒烯C_(60)/离子液体复合物修饰的纳米碳糊电极,建立了一种灵敏、快速检测苋菜红的新分析方法;利用循环伏安法(CV)对修饰电极进行了表征;利用方波伏安法(SWV)研究了苋菜红的电化学行为;根据不同扫速下的峰电流与扫速的关系讨论了苋菜红在电极表面的反应过程;优化了实验条件,讨论了干扰物质的影响。结果表明,富勒烯C_(60)/离子液体复合物修饰纳米碳糊电极对苋菜红表现出较好的选择性和较高的灵敏度,在最优的实验条件下,利用方波伏安法定量检测苋菜红,苋菜红的峰电流与浓度在0.5~20μmol/L之间呈线性关系(R2=0.990 6),检测限为0.1μmol/L(S/N=3);干扰研究表明,大部分干扰物质对苋菜红的检测无明显影响(相对标准偏差<±5%)。本实验制备的电化学传感器可用于实际样品的检测,样品回收率为95.0%~103.2%。 相似文献
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采用乙炔黑(AB)和离子液体(1-丁基-3-甲基咪唑六氟磷酸盐,[BMIM]PF6)作为复合修饰材料,制备了AB-离子液体复合修饰电极(AB-[BMIM]PF6/GCE)。用循环伏安法(CV)研究姜黄素在该修饰电极上的电化学行为。实验结果表明,在pH为6.5的磷酸盐缓冲液(PBS)中,姜黄素在该修饰电极上出现氧化峰。AB-离子液体分散液的最佳滴涂量为8μL,此时姜黄素检测的峰电流值最大且灵敏。在扫速为75 mV·s-1时,峰电流变化最大,表明此为最佳扫描速率。此时,峰电流值与姜黄素浓度呈线性关系,其线性方程为I(μA)=3.121 5C(mmol·L-1)+0.789 7,检测限为0.02 mmol·L-1。 相似文献
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核黄素(VB2)在液体石蜡碳糊电极上的伏安特性及脉冲伏安法测定 总被引:4,自引:0,他引:4
以液体石腊碳糊电极为工作电极,在0.1
mol/L NaCl(pH=2.5)底液中研究VB2的伏安特性.VB2有一对氧化还原峰,峰电位为氧化峰(I)-110
mV/还原峰(Ⅱ)-160 mV,结果表明溶液中VB2的电极过程主要受VB2表面吸附控制.VB2溶液受光照后,增加一对光色素的氧化还原峰,其峰电位为氧化峰(Ⅳ)-220mV/还原峰(Ⅲ)-280
mV.采用微分脉冲伏安法进行VB2的定量分析,线性范围为1×10-5~6.0×10-8moL/L,检测下限为2.00×10-8moL/L.测定复合VB药片中的VB2,RSD为2.1%,回收率为96.8~104%,其结果与药典中标准方法测定结果一致. 相似文献
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以加入一定量的季铵盐和离子液体的4-甲基-2-戊酮(MIBK)作为有机相,研究了一种测定碱性废水pH值的液/液界面电化学分析新方法。利用循环伏安法测试了OH-在液/液界面处的反应,实验证明该过程受扩散作用控制,并阐述了可能的机理。当季铵盐浓度达到0.05 g/mL时,液/液界面处OH-的交换能够达到饱和,峰电流大小由OH-浓度控制。同时还研究了温度对该体系的影响。OH-的峰电位在0.6 VvsSCE处,并且pH值在7~12范围内与峰电流成正比。对实际酞菁蓝染料废水的pH值进行检测,能够达到较好的准确度。 相似文献
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A new electrochemical method was proposed for the determination of thymine, which relied on the oxidation of thymine at a carbon ionic liquid electrode (CILE) in a pH 5.0 Britton-Robinson buffer solution. CILE was fabricated by using ionic liquid 1-(3-chloro-2-hydroxy-propyl)-3-methylimidazole acetate as the binder, which showed strong electrocatalytic ability to promote the oxidation of thymine. A single well-defined irreversible oxidation peak appeared with adsorption-controlled process and enhanced electrochemical response on the CILE, which was due to the presence of high conductive ionic liquid on the electrode. The reaction parameters of thymine were calculated with the electron transfer coefficient (α) as 0.27, the electron transfer number (n) as 1.23, the apparent heterogeneous electron transfer rate constant (ks) as 6.87 × 10−6 s−1 and the surface coverage (ГT) as 5.71 × 10−8 mol cm−2. Under the selected conditions the oxidation peak current was proportional to thymine concentration in the range from 3.0 to 3000.0 μM with the detection limit as 0.54 μM (3σ) by differential pulse voltammetry. The proposed method showed good selectivity to the thymine detection without the interferences of coexisting substances. 相似文献
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Ionic liquid, 1-heptyl-3-methylimidazolium hexafluorophosphate (HMIMPF6), has been used to fabricate two new electrodes, carbon ionic liquid electrode (CILE) and ionic liquid modified carbon paste electrode (IL/CPE), using graphite powder mixed with HMIMPF6 or the mixture of HMIMPF6/paraffin liquid as the binder, respectively. The electrochemical behaviors of hydroquinone at the CILE, the IL/CPE and the CPE were investigated in phosphate buffer solution. At all these electrodes, hydroquinone showed a pair of redox peaks. The order of the current response and the standard rate constant of hydroquinone at these electrodes were as follows: CILE > IL/CPE > CPE, while the peak-to-peak potential separation was in an opposite sequence: CILE < IL/CPE < CPE. The results show the superiority of CILE to IL/CPE and CPE, and IL/CPE to CPE in terms of promoting electron transfer, improving reversibility and enhancing sensitivity. The CILE was chosen as working electrode to determine hydroquinone by differential pulse voltammetry, which can be used for sensitive, simple and rapid determination of hydroquinone in medicated skin cosmetic cream. 相似文献
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Direct electrochemistry of double strand DNA on ionic liquid modified screen-printed graphite electrode 总被引:1,自引:0,他引:1
An ionic liquid modified screen-printed graphite electrode (SPE) was used for direct electrochemistry of herring sperm double strand DNA (dsDNA) by voltammetry. Due to the high conductivity of ionic liquid n-octylpyridinum hexafluorophosphate (OPPF), this electrode exhibited excellent electrochemical activity for the oxidation of dsDNA. Two irreversible oxidation peaks were obtained at the developed electrode, which corresponded to the oxidation of guanine and adenine residues present in the dsDNA. The basic electrochemical behavior of dsDNA at the OPPF modified SPE was carefully investigated. Combined with the differential pulse voltammetry, this electrode exhibited a good linear range from 20 μg mL−1 to 120 μg mL−1 with a detection limit of 5 μg mL−1 for the direct determination of dsDNA. Furthermore, the OPPF modified electrode displayed high reproducibility and stability for the dsDNA determination. 相似文献
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A multi-walled carbon nanotubes (MWCNTs) modified carbon ionic liquid electrode (CILE) was fabricated and used to investigate the electrochemical behavior of guanosine. CILE was prepared by mixing hydrophilic ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), graphite powder and liquid paraffin together. The fabricated MWCNTs/CILE showed great electrocatalytic ability to the oxidation of guanosine and an irreversible oxidation peak appeared at 1.067 V (vs. SCE) with improved peak current. The electrochemical behavior of guanosine on the MWCNTs/CILE was carefully studied by cyclic voltammetry and the electrochemical parameters such as the charge transfer coefficient (α) and the electrode reaction standard rate constant (ks) were calculated with the result as 0.66 and 2.94 × 10−4 s−1, respectively. By using differential pulse voltammetry (DPV) as the detection method, a linear relationship was obtained between the oxidation peak current and the guanosine concentration in the range from 1.0 × 10−7 to 4.0 × 10−5 mol/L with the detection limit as 7.8 × 10−8 mol/L (3σ). The common coexisting substances showed no interferences to the guanosine detection and the modified electrode showed good ability to distinguish the electrochemical response of guanosine and adenosine. 相似文献
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Ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was used to fabricate a new ionic liquid/carbon
paste electrode (IL/CPE). The general behavior of this electrode was characterized by electrochemical impedance spectroscopy,
cyclic voltammetry, and scanning electron microscopy. Results showed that the IL plays an important role in improving the
conductivity, reversibility, and electron transfer rate of the electrode. Nickel-modified ionic liquid/carbon paste electrode
(Ni/IL/CPE) was also constructed by immersion of the IL/CPE in 1.0 M nickel sulfate solution. IL showed significant effect
on the accumulation of nickel species on the surface of the electrode. The Ni/IL/CPE was applied successfully to highly efficient
(current density of 16.5 mA cm−2) electrocatalytic oxidation of formaldehyde in alkaline medium. Cyclic voltammetry and chronoamperometry techniques indicated
that this electrode displays a considerable electrocatalytic activity toward the oxidation of formaldehyde. The effects of
different scan rates and formaldehyde concentrations on the electrocatalytic activity of this modified electrode were investigated.
Finally, the rate constant for chemical reaction between formaldehyde and redox sites of the electrode was calculated. 相似文献
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Cyclic voltammogram of methiocarb in 0.1 M H2SO4 exhibited an irreversible anodic peak at about +1285 mV versus Ag/AgCl. Electro-oxidation and determination of methiocarb in spiked soil, river water and agrochemical formulation were realized on a newly prepared carbon-nanotube paste electrode by applying square wave voltammetry (SWV). The dE p /dpH value indicated that the oxidation mechanism involved the coupling of H+ with the oxidation process. The peak signals were linearly related to methiocarb concentration in the range of 1.5–59.1 mgL?1 with a detection limit of 0.45 mgL?1. The accuracy and selectivity of the proposed method were shown by calculating the recoveries of methiocarb from soil, river water and pesticide formulation Mesurol®. The calculated percent recoveries for soil and river water samples spiked with 30.0 μg g?1 and 40.0 μg mL?1 levels were 99.3 ± 1.2 and 98.5 ± 0.3 at 95 % confidence limit, respectively. 相似文献
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Cong Li Weilu Liu Yue Gu Shuming Hao Xiaoyi Yan Zhiquan Zhang Ming Yang 《Journal of Applied Electrochemistry》2014,44(9):1059-1067
A glassy carbon electrode (GCE) modified with poly(sulfosalicylic acid) (PSA) and poly(diallyldimethylammonium chloride)-graphene (PDDA-GN) was prepared by a simple self-assembly method. The formation of films was ascribed to the electrostatic force between negatively charged PSA and positively charged PDDA-GN as well as the π–π stacking interaction between PSA and PDDA-GN. The as prepared films were characterized by scanning electron microscopy (SEM), Raman spectroscopy and electrochemical methods. Under the optimized condition, the modified GCE showed two well-defined redox waves for catechol (CT) and hydroquinone (HQ) in cyclic voltammetry (CV) with a peak potential separation of 111 mV, which ensured the anti-interference ability of the electrochemical sensor and made simultaneous determination of dihydroxybenzene isomers possible in real samples. The corresponding oxidation currents increased remarkably compared with those obtained at the bare GCE, PSA/GCE and PDDA-GN/GCE, respectively. Differential pulse voltammetry (DPV) was used for the simultaneous determination of CT and HQ. The anodic peak current of CT was linear in the concentration from 1 × 10?6 to 4 × 10?4 M in the presence of 3 × 10?5 M HQ, and the detection limit was 2.2 × 10?7 M (S/N = 3). At the same time, the anodic peak current of HQ was linear in the concentration from 2 × 10?6 to 4 × 10?4 M in the presence of 2 × 10?5 M CT, and the detection limit was 3.9 × 10?7 M (S/N = 3). The proposed method was applied to simultaneous determination of CT and HQ in tap water with satisfactory results. These results indicated that PSA/PDDA-GN is a promising modified material with great potential in electrocatalysis and electrochemical sensing. 相似文献
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In this paper, two disposable screen-printed antimony film electrodes (SPSbFEs) modified with multi-walled carbon nanotubes (MWCNTs) and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), respectively for electrochemical stripping measurement are introduced. The modified screen-printed electrode substrate was prepared by homogeneously doping the attractive material into the graphite-based printing ink, and then an antimony film was in situ formed by simultaneously electrodepositing the antimony precursor with interesting analytes on the modified substrate. The electroanalytical performance of the modified SPSbFE for heavy metals based on the anodic stripping protocol was intensively evaluated. It was found that stripping voltammetric measurements of mercury (II) and lead (II) at the modified SPSbFEs resulted in good peaks with very low background contribution. In comparison with the bare SPSbFE, the modifications of both MWCNTs and [Bmim]BF4 were demonstrated providing more sensitive responses. The results indicated that the SPSbFE modified with 4 wt% [Bmim]BF4 exhibited well linear behavior in the mercury (II) concentration range from 20 to 140 μg/L (R2 = 0.998) with a detection limit of 0.36 μg/L (S/N = 3) under a 120 s accumulation, and good repeatability with a relative standard deviation (RSD) of 4.16% (40 μg/L, n = 12). The proposed electrodes, as new styles of “mercury-free” electrodes, also exhibit encouraging properties for measurements of practical samples. 相似文献
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《塑料、橡胶和复合材料》2013,42(7):279-283
AbstractNovel poly(ether ether ketone) (PEEK)/organically modified montmorillonite (OMMT) composites containing 0–10 wt-% fractions of OMMT were prepared by melting blending method and the microstructure, thermal and mechanical properties were investigated using different characterisation techniques. X-ray diffraction and transmission electron microscopy showed that the OMMT was well dispersed with microscale in the PEEK matrix. Differential scanning calorimetry indicated that the glass transition temperature T g and melt temperature T m of PEEK/OMMT composites (POMCs) were hardly affected by the addition of OMMT, while the crystal temperature T c decreased when the amount of OMMT excessed 1 wt-%. The data of thermogravimetric analysis exhibited that the thermal stability of POMCs in higher temperature region was better than that of pure PEEK. The results of mechanical properties test revealed that modulus and strength of POMCs increased with the content of OMMT, whereas the elongation at break and impact strength of POMCs decreased. 相似文献