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流动注射双安培法测定多巴胺 总被引:5,自引:0,他引:5
通过偶合多巴胺在铂电极上的氧化和高锰酸钾在铂电极上的还原,建立了一个不施加电压的条件下的流动注射双安培法直接测定多巴胺的新方法。以0.05 mol/L硫酸为载液,多巴胺的氧化峰电流与其浓度在0.8~160 mg/L范围内呈线性关系,线性回归方程为i(nA)=652.9C-239.2(r=0.9998,n=10),检出限为0.2 mg/L;RSD为2.86%(N=80 mg/L,n=14);进样频率为80次/h。本方法具有很高的选择性和灵敏度,样品处理方法简单快速,适于连续自动测定。用于实际样品的测定,结果满意。 相似文献
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Alexander Chebotarev Konstantin Pliuta Anastasiya Koicheva Kateryna Bevziuk Denys Snigur 《Analytical letters》2018,51(10):1520-1528
A simple disposable electrochemically activated carbon-paste electrode was developed for the determination of levodopa in pharmaceuticals and the optimal conditions for carbon-paste electrode electrochemical activation were studied. The study of the oxidation process of levodopa on the proposed electrode was performed using cyclic voltammetry and the irreversibility of levodopa with a kinetic-controlled current was established. The determination of levodopa is possible in the concentration range of 5–100?µM. The detection and quantification limits were 0.65 and 0.79?µM, respectively. The proposed procedure was satisfactorily applied in the levodopa determination in pharmaceuticals with relative standard deviation 3.4%. 相似文献
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Nanostructured Conducting Polymer/Copper Oxide as a Modifier for Fabrication of L‐DOPA and Uric Acid Electrochemical Sensor 下载免费PDF全文
A modified electrode was prepared by modification of the carbon paste electrode (CPE) with a nanostructured material. This nanostructure with electrocatalytic activity was synthesized by combination of poly pyrrole and copper oxide nanoparticles (PPy/CuO). The structure and morphology of PPy/CuO was studied. The fabricated modified electrode (CPE‐PPy/CuO) exhibited an excellent electrocatalytic activity toward levodopa (L‐DOPA) and uric acid (UA) oxidation because of high conductivity, low electron transfer resistance and catalytic effect. The CPE‐PPy/CuO had a lower overvoltage and enhanced electrical current with respect to the bare CPE for both L‐DOPA and UA. Also, the modified electrode showed a good resolution for the overlapped anodic peaks of L‐DOPA and UA. This electrode was used for the successful simultaneous determination of L‐DOPA and UA. The electrochemical sensor responded to L‐DOPA and UA in the concentration range of 0.050–1200 μM and 0.040–2000 μM, respectively. The detection limits were obtained by differential pulse voltammetry as 15 nM for L‐DOPA and 20 nM for UA. Finally, the proposed electrode was used for determination of L‐DOPA and UA in real samples using standard addition method. 相似文献
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本文对羟乙芦丁在玻碳电极上的阳极微分脉冲安行为进行了研究,发现在Na2HPO4溶液中(pH=8.95)于+0.64V(vs.Ag/AgCl)左右产生一个良好的阳极氧化伏安峰,浓度在5~60mg/L之间与峰电流呈线性关系,不需分离直接测定了片剂中的羟乙芦丁含量。电极反应为扩散速率控制的不可逆可程。 相似文献
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建立了毛细管电泳-紫外检测同时测定血清中左旋多巴和甲基多巴的方法。以40 mmol/L硼砂(pH 9.5)为分离缓 冲溶液,在3.45 kPa(0.5 psi)压力下进样7 s、分离电压22 kV、检测波长200 nm、温度25 ℃的条件下进行测定,两 种物质获得了较好的分离。甲基多巴和左旋多巴分别为1.0~64.0 mg/L和1.0~71.0 mg/L时与峰面积呈良好的线性关系, 线性相关系数分别为0.9998和0.9994,检出限分别为0.6和0.8 mg/L(以信噪比为3计)。将该法用于血清中甲基多巴和左 旋多巴的测定,回收率为82.8%~88.8%,相对标准偏差为2.10%~2.63%。 相似文献
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First Report for Electrochemical Determination of Levodopa and Cabergoline: Application for Determination of Levodopa and Cabergoline in Human Serum,Urine and Pharmaceutical Formulations 下载免费PDF全文
The electrochemical oxidation of levodopa on the surface of a carbon paste electrode modified with graphene nanosheets, 1‐(4‐bromobenzyl)‐4‐ferrocenyl‐1H‐[1,2,3]‐triazole (1,4‐BBFT) and hydrophilic ionic liquid (n‐hexyl‐3‐methylimidazolium hexafluoro phosphate) as a binder is studied. It has been found that the oxidation of levodopa at the surface of a modified electrode occurs at a potential of about 210 mV less positive than that of an unmodified carbon paste electrode (CPE). The prepared modified electrode exhibits a very good resolution of the voltammetric peaks of levodopa and cabergoline. The electrode has been applied successfully for the determination of levodopa and cabergoline in some real samples. 相似文献
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利用电化学方法制备了磷钼酸修饰电极,该修饰电极对溶液中的PO43-有很好的电流响应,继而提出了一种用纳米TiO2-K2S2O7共存体系光催化氧化有机磷生成正磷,然后以磷钼酸修饰电极进行测定的新方法。实验中以有机膦酸为标准物质,研究了测定机理,优化了测定条件。实验表明,本方法操作简单、快速、准确。PO43-在0.04~16 mg/L浓度范围内,与修饰电极上的电流响应呈线性关系,检出限为0.02 mg/L。用本方法测定实际水样与标准分析方法所得结果相近。 相似文献
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研究盐酸青藤碱在β-环糊精(β-CD)修饰碳糊电极上的电化学行为,在此基础上建立了测定盐酸青藤碱的电化学新方法。盐酸青藤碱在β-CD修饰碳糊电极上是受吸附控制的电化学反应过程,在p H 6.6的柠檬酸–柠檬酸钠底液中,盐酸青藤碱在β-CD修饰碳糊电极上产生一对良好的氧化还原峰,峰电位分别为0.458 V和0.086 V。氧化峰电流与盐酸青藤碱的质量浓度在3.658 5~91.462 5 mg/L范围内呈良好线性关系,线性相关系数为0.995 4,检出限为1.229 3 mg/L。该方法应用于正清风痛宁片中盐酸青藤碱含量的测定,测定结果的相对标准偏差为5.82%(n=7),回收率在95.7%~107.4%之间。该方法简便、快速,结果准确,可用于盐酸青藤碱的测定。 相似文献
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纳米PbO2修饰电极安培检测器流动注射法快速测定化学需氧量 总被引:4,自引:0,他引:4
采用以纳米PbO2修饰电极为工作电极的安培检测器,用流动注射法快速检测水体中的化学需氧量(COD).根据纳米PbO2修饰电极催化氧化电流的大小测定样品的COD值,在50-1 200 mg/L COD的范围内,电流响应与标准水样中的CODCr值呈线性关系,检出限为20 mg/L.该法不需对水样进行预处理,不使用有毒试剂,无二次污染,具有快速、简便、进样量少及工作电极使用寿命长等优点,与CODCr国家标准分析法对比具有较好的相关性. 相似文献
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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. 相似文献
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《Electroanalysis》2005,17(14):1309-1316
The detection limit (about 0.017 μg mL?1) for voltammetric determination of iodide (peak at +0.87 V vs. Ag/AgCl at pH 2) at a glutaraldehyde‐cross‐linked poly‐L ‐lysine modified glassy carbon electrode involving oxidation to iodine was found to be several orders of magnitude lower than that for the voltammetric determination on a bare glassy carbon electrode. This method was applied successfully to the determination of iodide in two medicinal formulations. Idoxuridine was determined indirectly at the same electrode by accumulating it first at ?0.8 V vs. Ag/AgCl. At this potential the C? I bond in the adsorbed idoxuridine is reduced giving iodide, which is then determined at the modified electrode. The method was successfully applied to the determination of idoxuridine in a urine sample. 相似文献
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Muhammad Saqib Elena V. Dorozhko Jiri Barek Vlastimil Vyskocil Elena I. Korotkova Anastasiia V. Shabalina 《Molecules (Basel, Switzerland)》2021,26(16)
Laser-reduced graphene oxide (LRGO) on a polyethylene terephthalate (PET) substrate was prepared in one step to obtain the LRGO grid electrode for sensitive carbaryl determination. The grid form results in a grid distribution of different electrochemically active zones affecting the electroactive substance diffusion towards the electrode surface and increasing the electrochemical sensitivity for carbaryl determination. Carbaryl is electrochemically irreversibly oxidized at the secondary amine moiety of the molecule with the loss of one proton and one electron in the pH range from 5 to 7 by linear scan voltammetry (LSV) on the LRGO grid electrode with a scan rate of 300 mV/s. Some interference of the juice matrix molecules does not significantly affect the LSV oxidation current of carbaryl on the LRGO grid electrode after adsorptive accumulation without applied potential. The LRGO grid electrode can be used for LSV determination of carbaryl in fruit juices in the concentration range from 0.25 to 128 mg/L with LOD of 0.1 mg/L. The fabrication of the LRGO grid electrode opens up possibilities for further inexpensive monitoring of carbaryl in other fruit juices and fruits 相似文献
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Ana Đurović Zorica Stojanović Dušan Rakić Nada Grahovac 《International journal of environmental analytical chemistry》2018,98(4):369-385
In this paper, a chronopotentiometric method for the determination of herbicide metamitron (MTM) using a glassy carbon electrode (GCE) and a thin film mercury electrode (TFME) as working electrodes is presented. MTM provided a well-defined reductive peak in the Britton–Robinson buffer on both working electrodes. Instrumental and chemical factors such as pH of the buffer, initial potential and reduction current influencing MTM chronopotentiometric response were optimised with the Box–Behnken experimental design. Under the optimal combination of factors, the analytical signal was linear in the MTM concentration range of 0.8–30 mg/L, with a detection limit of 68.53 µg/L using a TFME, and in the concentration range of 1–30 mg/L, with a detection limit of 92.91 µg/L using a GCE. The precision of the method was estimated as a function of repeatability and reproducibility, with the value of relative standard deviation lower than 2.6%. The applicability of the method was verified by direct analysis of MTM in spiked water samples and commercial pesticide formulations. The obtained results were in good agreement with those obtained using liquid chromatography/tandem mass spectrometry (LC-MS/MS) method, or with those labelled by the manufacturer. By using chronopotentiometry, neither extraction nor preconcentration procedures are necessary, thus making this method simple, cost-effective and more feasible for analytical routine analysis. 相似文献