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Analytica Chimica Acta

Weiheng Kong, Di Wu, Lian Xia, Xuefeng Chen, Guoliang Li, Nannan Qiu, Guang Chen, Zhiwei Sun, Jinmao You, Yongning Wu
Recently, α-glucosidase inhibitor has been widely used in clinic for diabetic therapy. In the present study, a facile and sensitive fluorescent assay based on enzyme activated inner filter effect (IFE) on nitrogen-doped carbon dots (CDs) was first developed for the detection of α-glucosidase. The N-doped CDs with green emission were prepared by a one-step hydrothermal synthesis and gave the fluorescence quantum yield of 30%, which were used as the signal output. Through α-glucosidase catalysis, 4-nitrophenol was released from 4-nitrophenyl-α-d-glucopyranoside (NGP)...
June 22, 2017: Analytica Chimica Acta
Anran Liu, Kaifei Yin, Li Mi, Mengyao Ma, Yuanjian Liu, Ying Li, Wei Wei, Yuanjian Zhang, Songqin Liu
Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn(2+) displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction...
June 22, 2017: Analytica Chimica Acta
Chaitanya Tondepu, Roxana Toth, Chelliah V Navin, Latevi S Lawson, Jason D Rodriguez
We present a four-step screening approach for unapproved drugs. The screening approach is both qualitative and quantitative in design in order to determine if the sample under study contains the correct and acceptable amount of the declared active pharmaceutical ingredient. Four commercially-available unapproved antibiotic and antiviral drugs were used in this study. Out of the 40 individual samples tested, 100% of the samples matched for the declared active pharmaceutical ingredient with no false positives...
June 22, 2017: Analytica Chimica Acta
Bi-Cheng Yang, Shu-Fen Fang, Xiao-Ju Wan, Yong Luo, Jiang-Yan Zhou, You Li, Yun-Jun Li, Feng Wang, Ou-Ping Huang
Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants with carcinogenic effect raising worldwide concerns. Hydroxylated PAHs (OH-PAHs) could be formed in the body as metabolites of PAHs in human urine samples and thus considered as biomarkers of PAH exposure. In this study, five OH-PAHs including 3-phenanthrol, 1-naphthol, 2-hydroxy fluorene, 1-hydroxprene and 6-hydroxy chrysene in human urine samples were selectively enriched by C18 solid-phase microextraction (SPME), then SPME fiber was connected high voltage and then was inserted into a glass-capillary to elute and ionize the analytes for mass spectrometric (MS) detection...
June 22, 2017: Analytica Chimica Acta
Dilshadbek T Usmanov, Kenzo Hiraoka, Hiroshi Wada, Masaya Matsumura, Sachiyo Sanada-Morimura, Hiroshi Nonami, Shinichi Yamabe
Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device...
June 22, 2017: Analytica Chimica Acta
Mohammad Saraji, Ali Shahvar
An iron-based metal-organic aerogel was synthesized using metal-organic framework nanoparticles and applied as a fiber coating for solid-phase microextraction (SPME). Chemical, thermal and morphological characteristics of the material were investigated. Headspace SPME followed by gas chromatography-electron capture detection was used for the determination of chlorobenzenes in the environmental samples. The key experimental factors affecting the extraction efficiency of the analytes, such as ionic strength, extraction and desorption temperature, and extraction time were investigated and optimized...
June 22, 2017: Analytica Chimica Acta
Yanting Shen, Fei Tian, Jing Tu, Rui Li, Zhenzhu Chen, Yunfei Bai, Qinyu Ge, Zuhong Lu
The reaction temperature is one of the main factors that affect the stability of emulsion PCR (emPCR). Focusing on this point, we applied the "DNA breathing" mechanism in BEAMing (Bead, Emulsion, Amplification, and Magnetic) and proposed a more stable emulsion amplification method. Compared to the conventional emPCR, this method provided excellent results. Firstly, more stable emulsion system resulted in higher percentage of single-molecular amplifications (73.17%). Secondly, an ordinary temperature-controlling device was enough...
June 22, 2017: Analytica Chimica Acta
Huan Wang, Qin Ma, Yanfeng Wang, Caihe Wang, Dongdong Qin, Duoliang Shan, Jing Chen, Xiaoquan Lu
Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant K2S2O8. The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology...
June 22, 2017: Analytica Chimica Acta
Nikolay Solovyev, Marco Vinceti, Peter Grill, Jessica Mandrioli, Bernhard Michalke
A new method of simultaneous redox speciation of iron (II/III), manganese (II/III), and copper (I/II) in cerebrospinal fluid (CSF) has been designed. For the separation of redox species strong cation exchange chromatography (SCX) with isocratic elution was employed. Species were detected using inductively coupled plasma sector field mass spectrometry (ICP-sf-MS), operating at medium resolution. The following parameters were optimized: analytical column, eluent composition and pH, CSF injection volume and dilution factor...
June 22, 2017: Analytica Chimica Acta
Man He, Lijin Huang, Bingshan Zhao, Beibei Chen, Bin Hu
For the determination of trace elements and their species in various real samples by inductively coupled plasma mass spectrometry (ICP-MS), solid phase extraction (SPE) is a commonly used sample pretreatment technique to remove complex matrix, pre-concentrate target analytes and make the samples suitable for subsequent sample introduction and measurements. The sensitivity, selectivity/anti-interference ability, sample throughput and application potential of the methodology of SPE-ICP-MS are greatly dependent on SPE adsorbents...
June 22, 2017: Analytica Chimica Acta
Sicheng Xiong, Yaofeng Zhou, Xiaolin Huang, Ruijin Yu, Weihua Lai, Yonghua Xiong
Herein, for the first time we report a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of ochratoxin A (OTA) by introducing a large size polymer beads loaded with quantum dots (QBs) as carrier of competing antigen for decreasing binding affinity to antibody and enhancing the fluorescent signal intensity. When using 255 nm QBs as carrier of competing antigen, the equilibrium dissociation constant of QB based competing antigen to antibodies can be tuned to 100 times higher than that of the horseradish peroxidase (HRP) based competing antigen by controlling labeled amounts of antigen on the surface of QBs...
June 15, 2017: Analytica Chimica Acta
Venkatadri Tekuri, Darshak R Trivedi
A new heterocyclic thiophene-2-caboxylic acid hydrazide based chemosensor R1 to R4 were designed, synthesized and characterized by various spectroscopic techniques like FT-IR, UV-Vis, (1)H NMR, (13)C NMR, Mass and SC-XRD. The chemosensor R3 showed a significant color change from colorless to yellow in the presence of Cu(2+) ions and chemosensor R4 showed a significant color change from colorless to yellow in the presence of Cd(2+) ions over the other tested cations such as Cr(3+), Mn(2+), Fe(2+), Fe(3+), Co(2+), Ni(2+), Zn(2+), Ag(2+), Al(3+), Pb(2+), Hg(2+), K(+), Ca(2+) and Mg(2+)...
June 15, 2017: Analytica Chimica Acta
Koh Yiin Hong, Alexandre G Brolo
The convergence between nanometric sensing (e.g. surface-enhanced Raman scattering - SERS) and lab-on-chip technologies has emerged as a potential revolutionary approach for a variety of "real-world" applications. Surface plasmons (SPs) can be excited on metal interfaces through light coupling to metallic surface gratings. The generation of SPs is a fundamental requirement for SERS. The work reported in this paper demonstrates a versatile procedure to prepare both large area (i.e. one inch(2)) and microarrays (μarrays) metallic gratings structures capable of supporting SP excitation (and SERS)...
June 15, 2017: Analytica Chimica Acta
Juntuo Zhou, Chunlei Liu, Dandan Si, Bing Jia, Lijun Zhong, Yuxin Yin
Advances in high-resolution mass spectrometers with faster scanning capabilities and higher sensitivities have expanded these instruments' functionality beyond traditional data-dependent acquisition in targeted metabolomics. Apart from the traditional multiple reaction monitoring strategy, the parallel reaction monitoring (PRM) strategy is also used for targeted metabolomics quantification. The high resolution and mass accuracy of full-scan (MS1) and tandem mass spectrometry (MS/MS) scan result in sufficient selectivity by monitoring all MS/MS fragment ions for each target precursor and simultaneously providing flexibility in assay method construction and post-acquisition data analysis...
June 15, 2017: Analytica Chimica Acta
Malak M Tfaily, Rosalie K Chu, Jason Toyoda, Nikola Tolić, Errol W Robinson, Ljiljana Paša-Tolić, Nancy J Hess
A vast number of organic compounds are present in soil organic matter (SOM) and play an important role in the terrestrial carbon cycle, facilitate interactions between organisms, and represent a sink for atmospheric CO2. The diversity of different SOM compounds and their molecular characteristics is a function of the organic source material and biogeochemical history. By understanding how SOM composition changes with sources and the processes by which it is biogeochemically altered in different terrestrial ecosystems, it may be possible to predict nutrient and carbon cycling, response to system perturbations, and impact of climate change will have on SOM composition...
June 15, 2017: Analytica Chimica Acta
Jianjun Li, Yun Liu, Qianping Liu, Junfeng Hui, Yangzi Liu
A novel method for determination of sodium cyclamate in foods was developed. In this method, a syringe was loaded with the homogeneous mixture of the sample, KMnO4 powder and silica dispersant and used as a matrix solid phase dispersion (MSPD) reactor. As the reactor was infiltrated with small amounts of concentrated HCl, cyclamate was converted to 2-chlorocyclohexanone quickly and effectively within 5 min and determined by HPLC on a reversed-phase column using UV detection at a wavelength of 310 nm. Comparing with the traditional derivatisation in solution, the better clean-up was provided using on-cartridge derivatisation of MSPD, and much time, labor, and expense were saved...
June 15, 2017: Analytica Chimica Acta
Zahra Mofidi, Parviz Norouzi, Shahram Seidi, Mohammad Reza Ganjali
For the first time, on-line and ultra-sensitive determination of trace amount of diclofenac in whole blood sample was performed by coupling of electromembrane extraction (EME) and stripping fast Fourier transform continuous cyclic voltammetry (SFFTCCV). In SFFTCCV, the potential waveform was continuously applied on a carbon paste electrode and the electrode response was obtained by subtracting the background current and integrating the current in potential range of the analyte oxidation. A central composite design was used for the optimization of the parameters influencing the extraction efficiency...
June 15, 2017: Analytica Chimica Acta
Sara Hooshmand, Zarrin Es'haghi
In this research, a novel sensitive electrochemical nanosensor based on the cadmium selenide quantum dots (QDs)/ionic liquid mediated hollow fiber-pencil graphite electrode (HF-PGE) was prepared and applied for simultaneous determination of uric acid (UA) and creatinine (Crn) in urine and serum samples. The electrocatalytic oxidation of the analytes was investigated via differential pulse (DPV) and cyclic voltammetry (CV). The experiments were designed, in two different steps, according to Taguchi's method; OA9 L9 (3(3)) and OA9 L9 (3(4)) orthogonal array to optimize experimental runs...
June 15, 2017: Analytica Chimica Acta
Felicia Seichter, Josef Vogt, Peter Radermacher, Boris Mizaikoff
During routine Fourier-Transform Infrared Spectroscopy (FTIR) based quantification of carbon dioxide in breath, it is necessary to account for a non-linear signal response to the analyte concentration and disturbance factors arising from the gas background matrix. These factors as well as day-to-day fluctuation should be corrected via calibration. We present a novel strategy to combine the information of previous calibrations with a minimal number of actual calibration measurements to obtain a precise calibration...
June 15, 2017: Analytica Chimica Acta
Dominic J Hare
No abstract text is available yet for this article.
June 15, 2017: Analytica Chimica Acta
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