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排序方式: 共有395条查询结果,搜索用时 15 毫秒
301.
Jacek Gębicki 《Electroanalysis》2011,23(8):1958-1966
The paper presents the results of investigation on a prototype sensor for measurements of benzaldehyde and formaldehyde in air. Sensitivity, limit of quantification and coefficient of selectivity of the sensor have been determined as a function of membrane thickness and electrode type using square wave voltammetry (SWV) technique. The working and counter electrodes were made of platinum and gold. Ionic liquids 1‐hexyl, 3‐methylimidazolium bis(trifluoromethanesulfonyl)imide constituted an internal electrolyte. Polydimethylsiloxane (PDMS) membrane separated gaseous medium from the electrolyte. 相似文献
302.
Virendra V. Singh M. Boopathi K. Ganesan Beer Singh R. Vijayaraghavan 《Electroanalysis》2010,22(12):1357-1363
Greener electrochemical detection method developed for chemical warfare agent (CWA) nitrogen mustard‐2 (NM‐2) using room temperature ionic liquid (RTIL). The diffusion coefficient calculated for NM‐2 in acetonitrile and RTIL was 1.57×10?4 cm2/s and 1.82×10?10 cm2/s, respectively. NM‐2 addition to RTIL enhanced RTIL conductivity. Moreover, heterogeneous rate constant (0.192 s?1), transfer coefficient (0.231) and the number of electron involved (1.0) were deduced for NM‐2 in RTIL. The calibration plot showed linearity between 2.94×10?5 and 1.17×10?3 M with detection limit 1.47 ×10?5 M (S/N=3). The large number of available RTIL can be used for greener detection of toxic CWAs. 相似文献
303.
Haijun Du Jianshan Ye Jiaqi Zhang Xiaodan Huang Chengzhong Yu 《Electroanalysis》2010,22(20):2399-2406
Graphene nanosheets modified glassy carbon electrode (GNs/GCE) was fabricated as voltammetric sensor for rutin with good sensitivity, selectivity and reproducibility. The sensor exhibits an adsorption‐controlled, reversible two‐proton and two electron transfer reaction for the oxidation of rutin with a peak‐to‐peak separation (ΔEp) of 26 mV as revealed by cyclic voltammetry. Moreover, the redox peak current increased about 14 times than that on bare glassy carbon electrode (GCE). The linear response of the sensor is from 1×10?7 to 1×10?5 M with a detection limit of 2.1 × 10?8 M (S/N = 3). The method was successfully applied to determine rutin in tablets with satisfied recovery. 相似文献
304.
Hui Huang Xingmei Liu Xueyu Zhang Weilu Liu Xingguang Su Zhiquan Zhang 《Electroanalysis》2010,22(4):433-438
Magnetic Fe3O4 nanoparticles functionalized multiwalled carbon nanotubes (nano‐Fe3O4 MWNTs) were prepared for electrochemical sensors. 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole was used as a connecter to form a network that connected nano‐Fe3O4 MWNTs to the Au electrode surface. Modified process of the electrode was studied with SEM, TEM and cyclic voltammetry. Cyclic voltammetry and amperometric i‐t curve were used to investigate characteristics of the obtained electrode. The sensor has been successfully used on the direct detection of catechol and showed excellent performances. The linear regression equation was Ipa(μA)=0.07763+0.16739 C (μmol/L); R=0.9993 and the detection limit was 5.38×10?8 mol/L. The modified electrode showed good reproducibility and stability. 相似文献
305.
Takuya Nakanishi Tsubasa Ueno Mariko Matsunaga Md. Zaved Hossain Khan Tetsuya Osaka 《Electroanalysis》2010,22(4):393-398
Potential response of indium tin oxide (ITO) electrode modified by treatment with disuccinimidyl suberate (DSS) was investigated to various target molecules. Distinctively, the DSS‐modified ITO electrode exhibited a potential shift to the molecules possessing an indole group such as tryptophan, tryptamine and indole propionic acid, while little response to benzoic acid, phenylalanine, proline, proline amide, and arginine was observed. In addition, the combination of this specificity to indoles and enantioselective affinity of human serum albumin (HSA), which was additionally immobilized on the DSS‐modified ITO electrode, brought about enantioselective potential response to tryptophan. 相似文献
306.
《Electroanalysis》2006,18(4):319-326
The unique chemical and physical properties of nanoparticles make them extremely suitable for designing new and improved sensing devices, especially electrochemical sensors and biosensors. Many kinds of nanoparticles, such as metal, oxide and semiconductor nanoparticles have been used for constructing electrochemical sensors and biosensors, and these nanoparticles play different roles in different sensing systems. The important functions provided by nanoparticles include the immobilization of biomolecules, the catalysis of electrochemical reactions, the enhancement of electron transfer between electrode surfaces and proteins, labeling of biomolecules and even acting as reactant. This minireview addresses recent advances in nanoparticle‐based electrochemical sensors and biosensors, and summarizes the main functions of nanoparticles in these sensor systems. 相似文献
307.
The colouristic and fluorescent characteristics of a new composite material based on a PAMAM dendrimer of second generation whose periphery is modified with 4-N,N-dimethylaminoethylamino-1,8-naphthalimide and polyamide-6 have been investigated. This dendrimer has been investigated with regard to its application as a heterogenic sensor capable of detecting metal cations and protons in aqueous solutions. In the presence of metal cations (Ni2+, Fe2+, Fe3+ and Co2+) and protons the fluorescence intensity of the composite increases due to their coordination with dendrimer molecule. The results obtained reveal the capacity of this system to act as a sensitive sensor of environmental pollution by metal cations and protons. It has been shown that in N,N-dimethylformamide solution the metal cations inhibit the processes of photodegradation of the dendrimer. 相似文献
308.
Cobalt(II) phthalocyanine [Co(II)Pc] is used as both an ionophore and chromogen for batch and flow injection potentiometric and spectrophotometric determination of anionic surfactants (SDS), respectively. The potentiometric technique involves preparation of a polymeric membrane sensor by dispersing [Co(II)Pc] in a plasticized PVC membrane. Under batch mode of operation, the sensor displays a near-Nernstian slope of −56.5 mV decade−1, wide response linear range of 7.8 × 10−4 to 8.0 × 10−7 mol L−1, lower detection limit of 2.5 × 10−7 mol L−1 and exhibits high selectivity for anionic surfactants in the presence of many common ions. Under hydrodynamic mode of operation (FIA), the slope of the calibration plot, limit of detection, and working linear range are −51.1 mV decade−1, 5.6 × 10−7 and 1.0 × 10−3 to 1.0 × 10−6 mol L−1, respectively. The spectrophotometric method is based on the use of [Co(II)Pc] solution in dimethylsulfoxide (DMSO) as a chromogenic reagent. The maximum absorption of the reagent at 658 nm linearly decreases with the increase of anionic surfactant over the concentration range 2-30 μg mL−1. The lower limit of detection is 1 μg mL−1 and high concentrations of many interfering ions are tolerated. Flow injection spectrophotometric measurements are carried out by injection of the surfactant test solution in a stream of the reagent in DMSO. The sample throughput, working range and lower detection limit are 25-30 samples h−1, 4-60 and 2 μg mL−1, respectively. The potentiometric and spectrophotometric techniques are applied to the batch and flow injection measurements of anionic surfactants in some commercial detergent products. The results agree fairly well with data obtained using the standard methylene blue spectrophotometric method. 相似文献
309.
A Simple and Renewable Nanoporous Gold‐based Electrochemical Sensor for Bisphenol A Detection 下载免费PDF全文
A sensitive and simple electrochemical sensor based on nanoporous gold (NPG) was developed for the detection of bisphenol A (BPA). NPG was prepared by the dealloying method. The NPG modified glassy carbon electrode (GCE) displayed excellent catalytic activity towards the electrooxidation of BPA. The mechanism of the electrooxidation of BPA on NPG/GCE sensor was inferred. The sensor showed a linear range from 0.1 μM to 50 μM with a detection limit of 12.1 nM BPA. Specially, a simple but effective approach was attempted to renew the used sensor. The application of the sensor for real sample analysis was demonstrated. 相似文献
310.
Shu Rui Ng Hongchang Pang Peng Chen Chang Ming Li Danny O'Hare 《Electroanalysis》2015,27(12):2745-2752
Methylene blue (MB+) and pyrrole were copolymerised to electrodeposit a novel electroactive polymer on a Au electrode which was assessed for O2 sensing. The electroactive polymer exhibits diffusion‐limited behaviour and an electrochemical, followed by catalytic (EC′) mechanism in the presence of dissolved O2. Notably, it is pH‐insensitive in both N2‐purged and air‐equilibrated phosphate buffered saline (PBS) from pH 4 to 8. It is stable over 18 days, possesses a good sensitivity of 256.335 µA mM?1 cm?2, wide linear range of 15 µM to 285 µM and detection limit of 1.47 µM (S/N=3) for dissolved O2. It is highly promising for use in biological investigations where pH fluctuations are expected. 相似文献