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1.
A highly sensitive thrombin electrochemical aptasensor with Pt nanoparticles, blocking reagent‐horseradish peroxidase (HRP) and inert graphene oxide (GO) as enhancers was successfully fabricated. Firstly, Pt nanoparticles with high surface to volume ratio could increase the amount of the immobilized redox probe hexacyanoferrate nanoparticles (NiHCFNPs) and effectively enhance the electron transfer. Secondly, HRP and Pt nanoparticles with high catalytic activity extremely amplify the electrochemical signal of NiHCFNPs toward H2O2. Lastly, inert graphene oxide (GO) labeled TBA could be used for enlarging the steric hindrance of thrombin. As a result, the aptasensor showed a high sensitivity with a detection limit of 500 fM. 相似文献
2.
An ultrasensitive method for the determination of dihydroxybenzens by flow injection (FI) chemiluminescence (CL) analysis was proposed for the first time. It was found that the CL intensity of luminol–lysozyme system could be significantly inhibited by dihydroxybenzens. The CL intensity decrements were linear with the logarithm of dihydroxybenzens concentrations over the ranges of 1.0 ~ 700 pg mL‐1 for hydroquinone (HQ), 5.0 ~ 700 pg mL‐1 for catechol (CT) and 10 ~ 7000 pg mL‐1 for resorcinol (RS), with the corresponding limits of detection of 0.7, 3.0 and 7.0 pg mL‐1, respectively. The proposed method was successfully applied to the determination of CT in tap water, rain water, river water and HQ in waste photographic developer samples, with recoveries from 93.5 to 105.8% and relative standard deviations (RSDs) less than 4.0% (n = 5). The possible interaction mechanism of lysozyme with dihydroxybenzens was discussed, and CT to lysozyme's binding constant and the thermodynamic parameters were given by the homemade FI–CL model. The results shown that the binding of dihydroxybenzens to lysozyme was spontaneous with the hydrophobic force. 相似文献
3.
XIONG Jin'en LI Shuang LI Yi CHEN Yingli LIU Yu GAN Junlan JU Jiahui XIAN Yaoling XIONG Xiaohui 《高等学校化学研究》2020,36(5):787-794
A biosensor based on self-assembled ssDNA(aptamer) and polyethylene glycol functionalized graphene oxide(GO-PEG) has been designed for sensing profenofos in food. The sensor has employed the fluorescence "on/off" switching strategy in a single step in homogeneous solution. Compared to traditional detection methods, the strategy proposed here is simple, convenient, fast and sensitive. Furthermore, compared with the general aptamer-GO structure, this aptamer-GO-PEG structure is in possession of a better detection performance, which is largely attributed to the improvement of the biocompatibility and the adjustment of the adsorption capacity of GO by grafting the blocking agent PEG onto the surface of GO. Additionally, the improved biocompatibility of GO shows better stability in salt solutions and physiological solutions, which is more conducive to its practical application in foods. In this project, profenofos had been detected with the proposed strategy, and the limit of detection has been controlled to be 0.21 ng/mL. This aptasensing assay has been applied to determining profenofos in (spiked)tap water, cabbage and milk with the recovery values ranging from 93.1% to 108.5%, from 90.8% to 113.2% and from 105.9% to 114.2%, respectively. 相似文献
4.
《Electroanalysis》2017,29(3):923-928
This work presents a simple green approach for the chemical synthesis of cobalt oxide nano hexagons (Co3O4 NHs) with an average size of 160±40 nm incorporated graphene nanosheets (GR). The techniques used to confirm the formation of GR−Co3O4 NHs are transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction spectroscopy (XRD). The dopamine (DA) sensor was fabricated by drop casting GR−Co3O4 NHs on the pre‐cleaned glassy carbon electrode (GCE). GR−Co3O4 modified GCE displayed a sensitive and selective electrochemical determination of DA compared to only GR and Co3O4 NHs modified GCE. Our fabricated sensor showed a wide linear range from 0.2 to 3443 μM with low limit of detection (84 nM) towards the determination of DA. The sensitivity of our fabricated sensor was calculated to be 108 μA mM−1 cm−2. As well, a significant storage stability, repeatability and reproducibility were attained by GR−Co3O4 NHs modified GCE. Human urine samples were targeted for the demonstration of practicality of our sensor. 相似文献
5.
A nanocomposite gel with a uniform porous structure and well‐controlled compositions prepared by mixing three‐dimensional graphene material with an ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate, is used for nitric oxide detection. It shows a fast response of less than 4 seconds, an excellent sensitivity of 11.2 µA cm−2 (µmol/L)−1 and an extremely low detection limit of 16 nM with a signal‐to‐noise ratio of 3 (S/N=3), a performance superior to that of reported works based on carbon nanotubes and nanoparticles. The high sensitivity is attributed to the large electroactive surface area of the graphene gel nanocomposite towards nitric oxide oxidation. The electrochemical behavior of the gel nanocomposite is investigated and explained. 相似文献
6.
采用荧光基团(FAM)标记的核酸适体作为识别元件,氧化石墨烯为淬灭剂,建立了一种高选择性、高灵敏度的核酸适体传感器.核酸适体与氧化石墨烯结合后,荧光淬灭,此时溶液无荧光;加入胰岛素后,溶液中荧光得到恢复.利用荧光分析法检测加入胰岛素前后,溶液中荧光强度的变化,获取了荧光适体传感器的线性度和灵敏度,实现对胰岛素浓度的测定.结果表明,在5×10-8 ~ 1×10-5 mol/L范围内,胰岛素的浓度与溶液中荧光强度有良好的线性关系,检出限为10 nmol/L.采用此方法检测胰岛素,操作简便,检测速度快,准确性高,选择性好,检出限低. 相似文献
7.
《Electroanalysis》2017,29(4):1038-1048
Novel insights into the strategy of highly precise, carbon‐based electrochemical sensors are presented by exploring the excellent properties of graphene oxide (GO) and multiwalled carbon nanotube composites (GO‐MWCNTs/CPE) for the sensitive determination of tramadol hydrochloride (TRH). Cyclic voltammetry, differential pulse voltammetry, chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) scanning electron microscopy, and X‐ray diffraction (XRD) techniques were used to characterize the properties of the sensor. The linear response obtained for TRH using the GO‐MWCNTs/CPE was found to be over the range of 2.0x10−9 to 1.1x10−3 M with a good linearity and high correlation (0.9996). The limits of detection and quantification were found to be 1.50x10−10 M and 4.99 x 10−10 M, respectively. The proposed sensor was applied for determination of TRH in the presence of presence of co‐formulated drugs ketorolac tromethamine (KTM) and paracetamol (PAR). The sensor was shown to successfully apply to the determination of TRH in plasma as real samples. Satisfactory recoveries of TRH from samples clearly revealed that the proposed sensor can be applied into clinical analysis, quality control and a routine determination of drugs in pharmaceutical formulations. 相似文献
8.
Manorama Singh Smita R. Bhardiya Ambika Asati Harendra Sheshma Ankita Rai Vijai K. Rai 《Electroanalysis》2021,33(2):464-472
Herein, we report construction of a ferrocene-reduced graphene oxide-Mn spinel modified glassy carbon electrode (Fc−G/Mn3O4/GCE) as a sensitive electrochemical probe for hydrazine detection via its oxidation. The synergistic effect of ferrocene, graphene oxide and Mn3O4 provides it a great electrocatalytic effect. The electrochemical investigations of Fc−G/Mn3O4/GCE were studied using cyclic voltammetry, while differential pulse voltammetry was utilized for recording the electrocatalytic sensing of hydrazine. The prepared Fc−G/Mn3O4 offers a platform for sensitive and selective detection of low-level hydrazine in two linear ranges from 0.045 to 108 μM and 108 to 653 μM with limit of detection 8.5 nM. Real sample analysis was also performed in local industrial water samples with satisfactory recovery results. 相似文献
9.
《Electroanalysis》2018,30(9):2185-2194
The synthesis of novel nanocomposites with great sensing enhancement has played an important role in analytical chemistry, especially in the electrochemical detection of drug molecules. In this work, we report a wet chemical method for the preparation of a gold nanoparticle coated β‐cyclodextrin functionalized reduced graphene oxide nanocomposite. A number of different analytical techniques including ultraviolet‐visible spectroscopy, fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive X‐ray spectroscopy were employed to characterize the as‐synthesized nanocomposite. With excellent electrocatalytic properties and high supramolecular recognition ability, the as‐synthesized nanocomposite was used to modify a glassy carbon electrode surface for the sensitive determination of ciprofloxacin using voltammetric technique. The current response of ciprofloxacin on the nanocomposite modified electrode was greatly enhanced compared to that on the bare and other modified electrodes. Using differential pulse voltammetry, the oxidation peak currents increased linearly with the ciprofloxacin concentrations in the range between 0.01 to 120 μM with a detection limit of 2.7 nM. The electrochemical testing results showed good stability and reproducibility. Therefore, the nanocomposite could be a potential candidate for the development of electrochemical sensors for sensitive and selective determination of ciprofloxacin or similar drugs in the future. 相似文献
10.
《Electroanalysis》2017,29(5):1350-1358
In our study, graphene oxide (GO) modified graphite electrodes were used for sensitive and selective impedimetric detection of miRNA. After chemical activation of pencil graphite electrode (PGE) surface using covalent agents (CA), GO modification was performed at the surface of chemically activated PGE. Then, CA‐GO‐PGEs were applied for impedimetric miRNA detection. The microscopic and electrochemical characterization of CA‐GO‐PGEs was performed by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The optimization of experimental conditions; such as GO concentration, DNA probe concentration and miRNA target concentration was performed by using EIS technique. After the hybridization occurred between miRNA‐34a RNA target and its complementary DNA probe, the hybrid was immobilized onto the surface of CA‐GO‐PGEs. Then, the impedimetric detection of miRNA‐DNA hybridization was performed by EIS. The selectivity of our assay was also tested under the optimum experimental conditions. 相似文献
11.
采用光化学还原方法制备了图案化的石墨烯薄膜.研究了光还原氧化石墨烯薄膜(PRGO)的热稳定性和发光性质.热重分析(TGA)结果表明,光化学还原主要引起氧化石墨烯(GO)氧化基团的减少,而对GO内水含量影响较小;发光(PL)测试结果表明,不同激发条件下,PRGO的发光与GO相比表现出了不同的变化规律:在波长514 nm的光激发下,PRGO的发光强度比GO明显降低,同时伴随着发光峰峰位红移;而在波长830 nm的光激发下,PRGO的发光强度比GO略有增强,并且发光峰峰位无明显变化,此结果表明不同尺寸的碳团簇局域态(sp2C团簇)的光还原反应活性不同,这与GO特殊的能带结构密切相关. 相似文献
12.
Arockiajawahar Anancia Grace Sukumar Thillaiarasi Venkataraman Dharuman 《Electroanalysis》2021,33(4):993-1006
Tungsten oxide (W) decorated titanium oxide (T) adsorbed onto a graphene (Gr) and modified the glassy carbon electrode for the electrochemical quantification of riboflavin (RF) in edible food and pharmaceuticals. For comparison, nanocomposites are formed using graphene oxide (GO), reduced graphene oxide (rGO) and pure graphite (G) sheets to study the electrochemical activities towards riboflavin. The ternary WTGr modified GCE shows the highest electrocatalytic activity due to synergetic interactions between the metal oxide and graphene. The electrochemical observations are supported by the SEM, HRTEM, XRD, UV-Vis, Zeta potential (ζ) and size data. The sensor shows a wide linear range 20 nM–2.5 μM with a detection limit 25.24 nM and sensitivity (4.249×10−8 A/nM). The fabricated sensor is validated in real samples. 相似文献
13.
Comparison of Adsorption of Proteins at Di erent Sizes on Pristine Graphene and Graphene Oxide
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Zuo-si Yu Yi-yi Gao Xiao-gang Wang Guo-quan Zhou Song-wei Zeng Jun-lang Chen 《化学物理学报(中文版)》2018,31(1):85-91
Using all-atom molecular dynamics (MD) simulations, we have investigated the adsorption stability and conformation change of different proteins on the surface of pristine graphene (PG) and graphene oxide (GO). We find that: (ⅰ) with the cooperation of the electrostatic interactions between proteins and oxygen-containing groups, GO shows better adsorption stability than PG; (ⅱ) the peptide loses its secondary structure on both PG and GO surface, and the α-helix structure of the protein fragment is partially broken on PG surface, but is well preserved on GO surface, while the secondary structure of globular protein has no distinct change on both PG and GO surface. In general, GO presents better biocompatibility than PG. Our results are of significant importance to understand the interactions between proteins and PG/GO and the applications of PG/GO in biotechnology and biomedicine. 相似文献
14.
《Electroanalysis》2005,17(11):1008-1014
Using a graphite electrode modified with vaseline and NiO, ranitidine showed a strongly ECL enhancing effect for the weak ECL signal of electrooxidation of luminol. Based on this finding, a more sensitive ECL method for ranitidine was firstly proposed. Under the optimum experimental conditions, the ranitidine hydrochloride concentration in the range of 3.0×10?8–9.0×10?6 mol/L was proportional to the enhancing ECL signal and offered a 9×10?9 mol/L detection limit for ranitidine hydrochloride. At the same time, based on the investigation on this ECL reaction mechanism, a new concept, to improve the suitable ECL reaction micro‐environment with chemically modified electrode technique for the better analytical performances of ECL analysis was also firstly proposed. 相似文献
15.
This study compares the electrocatalytic activities of chemically reduced graphene oxide (crGO) and electrochemically reduced graphene oxide (erGO), which are both noncovalently functionalized with a polyaromatic dye, poly(methylene blue) (polyMB), toward the oxidation of β‐nicotinamide adenine dinucleotide (NADH). PolyMB‐crGO and polyMB‐erGO composites were obtained via electropolymerization of methylene blue on crGO and GO modified glassy carbon (GC) electrodes, respectively. Cyclic voltammetry (CV) results indicate that these two types of integrated electrodes reveal different electrocatalytic activities. PolyMB‐crGO integrated electrode possesses lower catalytic oxidation potential, suggesting higher catalytic activity. The present study is helpful for the understanding and screening of graphene‐based advanced carbon nanomaterials for potential electrochemical applications. 相似文献
16.
反相流动注射化学发光法测定单宁 总被引:8,自引:0,他引:8
在碱性介质中 ,单宁对高碘酸钾氧化鲁米诺的化学发光反应有较强的增敏作用 ,据此建立了反相流动注射化学发光测定单宁的新方法 ,并研究了最佳反应条件。该方法快速、准确、线性范围宽 ,测定单宁的检出限为 1 .1 2× 1 0 - 9g/ m L,方法的线性范围为 2 .0× 1 0 - 8~ 6 .0× 1 0 - 6 g/ m L,对于 4.0× 1 0 - 6 g/ m L单宁 1 0次测定的相对标准偏差为 0 .79%。应用于中药五倍子、诃子中单宁的测定 ,结果满意 相似文献
17.
18.
《Analytical letters》2012,45(1-3):4-11
A modified Trautz–Schorigin reaction, by using tannic acid-H2O2 system for the oxidation and determination of two kinds of carbonyl compounds was developed in this paper. It was found that formaldehyde and acetaldehyde could effectively enhance the chemiluminescence signals of tannic acid–H2O2 system in alkaline medium. Under optimized conditions, the proposed method has a linear range of 7 × 10?9–1 × 10?4 mol L?1 for formaldehyde and 1 × 10?8–1 × 10?4 mol L?1 for acetaldehyde with detection limits of 9 × 10?11 and 3 × 10?10 mol L?1, respectively. The relative standard deviations for 15 repeated measurements of 1 × 10?6 mol L?1 HCHO and CH3CHO are 1.13% and 1.65%, respectively. Analysis time per sample is 35 seconds. A comparison of results found by the proposed method with those obtained by a standard reference method provided good agreement. The proposed method is simple, rapid, convenient, and sensitive. 相似文献
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20.
Graphene Oxide/ZnO Nano Composite for Sensitive and Selective Electrochemical Sensing of Levodopa and Tyrosine Using Modified Graphite Screen Printed Electrode
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Determination of levodopa and tyrosine as two important species for treatment of Parkinson's disease is described. A novel electrochemical sensor involving graphene oxide/ZnO nanorods (GR/ZnO) nano composite and the graphite screen‐printed electrodes (GSPE) was developed for the simultaneous detection of levodopa and tyrosine. The screen‐printed electrodes with several advantages, including low cost, versatility and miniaturization were employed. On the other hand, the graphene oxide/ZnO nanorods nano composite was casted on the surface of GSPE to obtain GR/ZnO/SPE. The proposed nano sensor has excellent performance such as high sensitivity, good selectivity and analytical application in real samples. The combination of graphene oxide/ZnO nanorods nano composite with the screen‐printed electrode is favorable for amplifying electrochemical signals. Under optimized conditions square wave voltammetry (SWV) exhibited linear dynamic ranges from 1.0×10?6 to 1.0×10?3 M and 1.0×10?6 to 8.0×10?4 M with detection limits of 4.5×10?7 M and 3.4×10?7 M for levodopa and tyrosine respectively. 相似文献