ELECTROCHIMICA ACTA
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2013
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IF 3.777
Dan-Ling Zhou,Jiu-Ju Feng,Lin-Yi Cai,Qin-Xue Fang,Jian-Rong Chen,Ai-Jun Wang
In this work, well-defined monodisperse porous Cu 2 O nanospheres were facilely synthesized, using ionic liquid crystal 1-hexadecyl-2,3-dimethylimidazolium bromide ([C 16 MMIm]Br) as a soft template. The as-prepared Cu 2 O nanospheres were successfully anchored on the reduced graphene oxide nanosheets (RGOs) by simple ultrasonication. The RGOs-Cu 2 O nanocomposites showed high electrocatalytic activity toward glucose oxidation. Thus, a non-enzymatic amperometric glucose sensor was constructed with a wide linear range from 0.01 to 6 mM, low detection limit of 0.05 μM ( S/N = 3), high selectivity (185 μA mM −1 ), and fast response (within 3 s). This strategy opens a new facile and simple chemical route to prepare porous metal oxides supported on RGOs with novel properties.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
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2013
·Vol. 18
·期 1
·105-113
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IF 2.279
Li Hongying,Wang Xueliang,Yu Zhangyu
An electrochemical sensor for simultaneous determination of dopamine (DA), uric acid (UA), guanine (G), and adenine (A) has been constructed by copolymerizing melamine monomer and Ag ions on a glassy carbon electrode (GCE) with cyclic voltammetry. The poly-melamine and nano Ag formed a hybridized film on the surface of the GCE. The morphology of the film was characterized by scanning electron microscope. The electrochemical and electrocatalytic properties of this film were characterized by cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry (SWV). In 0.1 M phosphate buffer solution (pH 4.5), the modified electrode resolved the electrochemical response of DA, UA, G, and A into four well-defined voltammetric oxidation peaks by SWV; the oxidation peak current of DA, UA, G, and A increased 13-, 6-, 7-, and 9-fold, respectively, compared with those at the bare GCE and the SWV peak currents of DA, UA, G, and A with linear concentrations in the ranges of 0.1–50, 0.1–50, 0.1–50, and 0.1–60 μM, respectively. Based on this, a method for simultaneous determination of these species in mixture was setup. The detection limits were 10 nM for DA, 100 nM for UA, 8 nM for G, and 8 nM for A.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2013
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IF 3.554
Tao Qian,Chenfei Yu,Shishan Wu,Jian Shen
Gold nanoparticles coated polystyrene/reduced graphite oxide (AuNPs@PS/RGO) microspheres have been successfully prepared via a facile process, and the decorative gold nanoparticles could prevent the aggregation of RGO by electrostatic repulsive interaction, and lead to high dispersibility of the composite. The prepared composite has a highly increased conductivity of 129 S m −1 due to the unique electrical properties of citrate reduced gold nanoparticles. Being employed as an electrochemical sensor for detection of dopamine, the modified electrode exhibits remarkable sensitivity (3.44 μA/μM) and lower detection limit (5 nM), with linear response in a range of 0.05–20 μM. Moreover, valid response to dopamine obtained in present work also indicates the prospective performances of AuNPs@PS/RGO microspheres to other biological molecules, such as nucleic acids, proteins and enzymes.
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BIOSENSORS & BIOELECTRONICS
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2015
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IF 6.409
Yuliang Li,Junlin He,Yazhen Niu,Chao Yu
In this paper, a simple, ultrasensitive and label-free electrochemical α2,6-sialylated glycans biosensor based on reduced graphene oxide-tetraethylene pentamine-1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) hybrids was developed. Due to the abundance of amino groups from reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) and the electrostatic interaction of BMIMPF 6 , bimetallic gold platinum alloy nanoparticles (AuPtNPs) were densely adsorbed onto the surface of the nanocomposite , providing a large surface area available for the immobilization of Sambucus nigra agglutinin (SNA). AuPtNPs have excellent conductivity and catalytic activity , which can promote electron transfer between the electrolyte solution and the surface of electrode and can enhance the sensitivity of biosensor. SNA, which specifically binds α2,6-sialylated glycans, was covalently immobilized on AuPtNPs for specific detection of α2,6-sialylated glycans in human serum. Under optimal experimental conditions, amperometric response changes were used to detect α2,6-sialylated glycans with a broad linear range of 10 fg mL −1 –1 μg mL − 1 and a low detection limit of 3 fg mL − 1 ( S / N =3). When applied to spiked serum samples, the recovery of the developed biosensor ranged from 100.8% to 101.4%, suggesting that the electrochemical biosensor would be suitable for the practical detection of α2,6-sialylated glycans.
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TALANTA
·
2015
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IF 3.545
Jie Tang,Xiang Zhu,Xiangheng Niu,Tingting Liu,Hongli Zhao,Minbo Lan
In the present work, a high-performance enzyme-based electrochemical sensor for the detection of superoxide anion radical (O 2 ●− ) is reported. Firstly, we employed a facile approach to synthesize PtPd nanoparticles (PtPd NPs) on chemically reduced graphene oxide (RGO) coated with polydopamine (PDA). The prepared PtPd-PDARGO composite was well characterized by transmission electron microscopy , scanning electron microscopy, Fourier transform infrared spectra , X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. Then the assembled composite was used as a desired electrochemcial interface for superoxide dismutase (SOD) immobilization. Owing to the PDA layer as well as the synergistic effect of PtPd NPs, the fabricated SOD/PtPd-PDARGO sensor exhibited an outstanding sensitivity of 909.7 μA mM −1 cm −2 upon O 2 ●− in a linear range from 0.016 mM to 0.24 mM ( R 2 =0.992), with a low detection limit of 2 μM (S/N=3) and excellent selectivity, good reproducibility as well as favorable long-term stability.
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BIOSENSORS & BIOELECTRONICS
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2015
·
IF 6.409
Sijing He,Qiyou Wang,Yanyan Yu,Qiujia Shi,Lin Zhang,Zuanguang Chen
A novel, label-free and inherent electroactive redox immunosensor for ultrasensitive detection of carcinoembryonic antigen (CEA) was proposed based on gold nanoparticles (AuNPs) and potassium ferricyanide-doped polyaniline (FC-PANI) nanoparticles . FC-PANI composite was synthesized via oxidative polymerization of aniline, using potassium ferricyanide (K 3 [Fe(CN) 6 ]) as both oxidant and dopant . FC-PANI acting as the signal indicator was first fixed on a gold electrode (GE) to be the signal layer. Subsequently, the negatively charged AuNPs could be adsorbed on the positively charged FC-PANI modified GE surface by electrostatic adsorption, and then to immobilize CEA antibody (anti-CEA) for the assay of CEA. The CEA concentration was measured through the decrease of amperometric signals in the corresponding specific binding of antigen and antibody. The wide linear range of the immunosensor was from 1.0 pg mL −1 to 500.0 ng mL −1 with a low detection limit of 0.1 pg mL −1 (S/N=3). The proposed method would have a potential application in clinical immunoassays with the properties of facile procedure, stability, high sensitivity and selectivity .
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Analytical Methods
·
2013
·Vol. 5
·期 19
·5227-5233
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IF 1.855
Sha Peng,Jing Cheng,Miao Zhang,Mi Chen,Hongbin Zhou,Min Cheng
A very simple and effective method for the extraction and determination of oleanolic acid (OA) and ursolic acid (UA) in Radix Actinidiae chinensis was developed using ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) and high performance liquid chromatography–mass spectrometry (HPLC–MS). Ethanol was used as the solvent to extract OA and UA from Radix Actinidiae chinensis, assisted by ultrasonic waves. When the extraction process was finished, the two target analytes in the extraction solvent were rapidly transferred from the ethanol extract to another extraction solvent (chloroform) with the help of a dispersive solvent (tetrahydrofuran) by using DLLME. A series of extraction parameters were investigated and optimized. Under the most favorable conditions, the limits of detection (LOD, S/N = 3) and enrichment factors were 2.0 ng g−1, 89.4 and 6.0 ng g−1, 84.5 for OA and UA, respectively. The recoveries of the spiked sample solutions at three different concentration levels of 200, 500 and 1000 ng g−1 ranged between 88.2 and 96.6%. The proposed method was the first successfully applied for the extraction and determination of OA and UA in Radix Actinidiae chinensis.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2015
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IF 2.912
Yirong Jiang,Shuqin Mao,Weisu Huang,Baiyi Lu,Zengxuan Cai,Fei Zhou,Maiquan Li,Tiantian Lou,Yajing Zhao
Variations of phenylethanoid glycoside profiles and antioxidant activities in Osmanthus fragrans flowers through the digestive tract were evaluated by a simulated digestion model and UPLC/PDA/MS. Major phenylethanoid glycosides and phenolic acids, namely, salidroside, acteoside, isoacteoside, chlorogenic acid, and caffeic acid, were identified in four cultivars of O. fragrans flowers, and the concentration of acteoside was the highest, being up to 71.79 mg/g dry weight. After simulated digestion, total phenylethanoid glycoside contents and antioxidant activities were significantly decreased. Acteoside was identified as decomposing into caffeic acid, whereas salidroside was found to be stable during simulated digestion. According to Pearson’s correlation analysis, acteoside contents showed good correlations with antioxidant activities during simulated digestion (R2 = 0.994, P < 0.01). In conclusion, acteoside was the major contributor to the antioxidant activity of O. fragrans flowers, and salidroside was considered as the major antioxidant compound of O. fragrans flowers in vivo.
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CHEMICAL ENGINEERING JOURNAL
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2015
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IF 4.321
Jing Luo,Jun Sun,Jing Huang,Xiaoya Liu
This paper reports the design and synthesis of a novel molecular imprinted conductive polyaniline (PANI) nanoparticles (NPs) using polymeric micelle as nanoreactor. In our strategy, an amphiphilic acrylic copolymer was firstly synthesized which self-assemble into micelles in aqueous solution. The aniline monomer and template molecules (paracetamol, PCM) were then immobilized into polymeric micelle owing to their interactions. The subsequent polymerization of aniline occurred within the micelle with the addition of ammonium persulfate (APS), leading to the formation of molecular imprinted PANI NPs. The resulting PANI NPs were characterized by various techniques, including Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM). A highly sensitive and selective electrochemical sensor for detecting PCM was developed using the obtained molecular imprinted PANI NPs as recognition element. The obtained imprinted PANI sensor revealed not only high selectivity toward paracetamol, but also a wider linear range over paracetamol concentration from 0.4–100 μM and 200–1000 μM with a significantly lower detection limit of 50 nM, compared to previously reported PCM electrochemical sensors. The wide linear range was attributed to numerous effective recognition sites among the PANI matrix due to the large specific surface area of PANI NPs, whereas the low detection limit should be attributed to the electrical conductivity of PANI which provides a direct path for the conduction of electrons from the imprinting sites to the electrode surface. In addition, good stability and repeatability have also been demonstrated. This work not only provides a new type of paracetamol sensor with good performance, more importantly it develops a novel imprinting strategy to prepare molecular imprinted conductive nanoparticles in aqueous solution. In addition, considering the versatility of the amphiphilic copolymers, this strategy can be extended to imprint other molecules and thus prepare advanced MIP sensors for a wide range of templates.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Zheng-peng Yang,Xuan Liu,Chun-jing Zhang,Bao-zhong Liu
Transparent photocatalytic surfaces are of ever increasing importance for the enhancement of the photocatalytic efficiency. Here, the highly ordered transparent TiO 2 nanotube arrays were prepared by the anodization and thermal annealing of titanium layer deposited onto the glass substrate , and a novel nonenzymatic piezoelectric sensor was developed for urea detection based on the modification of molecularly imprinted TiO 2 thin film onto transparent TiO 2 nanotube arrays. The performance of the fabricated sensor was evaluated and the results indicated that the sensor exhibited high sensitivity in urea detection, with a linear range from 0.04 to 120 μM and a limit of detection of 0.01 μM. Moreover, the sensor presented outstanding selectivity while used in coexisting systems containing various interferents with high concentration. The analytical application of the urea sensor confirmed the feasibility of urea detection in urine sample.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Fengying Ye,Chenqi Feng,Ning Fu,Huihui Wu,Jibo Jiang,Sheng Han
A home-made carbon paste electrode (CPE) was reformed by graphene oxide (GO)/lanthanum (La) complexes, and a modified electrode, called GO–La/CPE, was fabricated for the selective determination of dopamine (DA) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Several factors affecting the electrocatalytic performance of the modified sensor were investigated. Owning to the combination of GO and La ions, the GO–La/CPE sensor exhibited large surface area, well selectivity, good repeatability and stability in the oxidation reaction of DA. At optimal conditions, the response of the GO–La/CPE electrode for determining DA was linear in the region of 0.01–0.1 μM and 0.1–400.0 μM. The limit of detection was down to 0.32 nM (S/N = 3). In addition, this modified electrode was successfully applied to the detection of DA in real urine and serum samples by using standard adding method, showing its promising application in the electroanalysis of real samples.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Wenjuan Guo,Na Sun,Xiaoli Qin,Meishan Pei,Luyan Wang
A novel aptasensor based on a novel composite film consisting of multi-walled carbon nanotubes (MWCNTs), ionic liquid (IL) of 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF 6 ), and nanoporous PtTi (NP-PtTi) alloy was constructed for ultrasensitive detection of kanamycin . The NP-PtTi alloy was successfully fabricated by a simple dealloying of PtTiAl source alloy in HCl solution. The NP-PtTi alloy has uniform interconnected network structure with specific surface area and was used to immobilize aptamer. After modified with the composite material, current signal was amplified obviously, which attributed to the larger specific surface area and excellent electrical conductivity of NP-PtTi and MWCNTs. A number of factors affecting the activity of the aptasensor have been discussed and optimized. Under the optimized conditions, the proposed aptasensor provided a linear range of 0.05–100 ng mL −1 with a low detection limit of 3.7 pg mL −1 . This aptasensor displayed high sensitivity, stability and reproducibility. In addition, the as-prepared aptasensor was successfully used for the determination of kanamycin in a real sample.
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