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Analytical Chemistry

Koushik Dhara, Somenath Lohar, Ayan Patra, Priya Roy, Swadhin Kumar Saha, Gobinda Chandra Sadhukhan, Pabitra Chattopadhyay
A lysosome targetable fluorogenic probe, LysoFP-NO2, was designed and synthesized based on naphthalimide fluorophore that can detect selectively carbon monoxide (CO) in HEPES buffer (pH 7.4, 37 °C) through the transformation of nitro to the amino functionalized system in presence of CO. LysoFP-NO2 triggered a 'turn-on' fluorescence response to CO with a simultaneous increase of fluorescence intensity by more than 75-times. The response is selective over a variety of relevant reactive nitrogen, oxygen and sulfur species...
January 22, 2018: Analytical Chemistry
Lanteng Wang, Wen Meng Jiang, Xing Shen, Xiangmei Li, Xinan Huang, Zhenlin Xu, Yuanming Sun, Shun-Wan Chan, Lingwen Zeng, Sergei Alexandrovich Eremin, Hongtao Lei
Immunoassay methods are important to monitor β-agonists illegally used for reducing animal fat deposition in livestock. However, there is no a simultaneous screening surveillance immunoassay for possibly occurred various β-agonist chemicals in food. In this study, using an R-(-)-salbutamol derivative as the immunizing hapten, an antibody recognizing 31 β-agonists and analogues was generated for the first time. Three-dimensional quantitative structure-activity relationship (3D QSAR) revealed that strong steric and hydrophobic fields around the hapten spacer near C-2, as well as a chirality at C-1´, dominantly modulated the class specificity of the raised antibody...
January 21, 2018: Analytical Chemistry
Tianlu Chen, Yijun You, Guoxiang Xie, Xiaojiao Zheng, Aihua Zhao, Jiajian Liu, Qing Zhao, Shouli Wang, Huang Fengjie, Cynthia Rajani, Chongchong Wang, Shaoqiu Chen, Yan Ni, Herbert Yu, Youping Deng, Xiaoyan Wang, Wei Jia
There is increased appreciation for the diverse roles of the microbiome-gut-brain axis on mammalian growth and health throughout the lifespan. Numerous studies demonstrated that gut microbiome and their metabolites were involved extensively in the communication of brain and gut. Association study of brain metabolome and gut microbiome is an active field offering large amount of information on the interaction of microbiome, brain and gut while data size and complicated hierarchical relationships were the major obstacles...
January 21, 2018: Analytical Chemistry
John A Mering, Shaun L L Barker
New methodology is presented for analyzing hydrogen isotope ratios (D/H) in phyllosilicate minerals by laser absorption spectroscopy. D/H measurements were carried out using an OA-ICOS instrument operated in a continuous flow configuration. Water was extracted from minerals in a high temperature quartz column and advanced to the analyzer in a dry air carrier gas stream. We report the first D/H measurements by a laser system for serpentine, muscovite, sericite, talc, and biotite. We also measure kaolinite, gypsum, and small volumes of water...
January 20, 2018: Analytical Chemistry
Makusu Tsutsui, Masayoshi Tanaka, Takahiro Marui, Kazumichi Yokota, Takeshi Yoshida, Akihide Arima, Wataru Tonomura, Masateru Taniguchi, Takashi Washio, Mina Okochi, Tomoji Kawai
Bioinspired pore sensing for selective detection of flagellated bacteria was investigated. The Au micropore wall surface was modified with a synthetic peptide designed from toll-like receptor 5 (TLR5) to mimic the pathogen-recognition capability. We found that intermolecular interactions between the TLR5-derived recognition peptides and flagella induce ligand-specific perturbations in the translocation dynamics of Escherichia coli, which facilitated the discrimination between the wild-type and flagellin-deletion mutant (ΔfliC) by the resistive pulse patterns thereby demonstrating the sensing of bacteria at a single-cell level...
January 19, 2018: Analytical Chemistry
Xingrui Li, Dongfeng Zhang, Huimin Zhang, Zhichao Guan, Yanling Song, Ruochen Liu, Zhi Zhu, Chaoyong James Yang
Compartmentalization of aqueous samples in uniform emulsion droplets has proven to be a useful tool for many chemical, biological, and biomedical applications. Herein, we introduce an array-based emulsification method for rapid and easy generation of monodisperse agarose-in-oil droplets in a PDMS microwell array. The microwells are filled with agarose solution, and subsequent addition of hot oil results in immediate formation of agarose droplets due to the surface-tension of the liquid solution. Because droplet size is determined solely by the array unit dimensions, uniform droplets with pre-selectable diameters ranging from 20 µm to 100 µm can be produced with relative standard deviations less than 3...
January 19, 2018: Analytical Chemistry
Mang Lin, Mark H Thiemens
An ultra-low-level liquid scintillation counting (LSC) technique has been used in measuring radiosulfur (cosmogenic 35S) in natural samples. The ideal half-life of 35S (~87 d) renders it a new way to examine various biogeochemical problems. A major limit of the technique is that complex chemical compositions in atmospheric samples may lead to color quenching of LSC cocktails, a serious problem prolonging the pretreatment time (>1 week) and hampering the accurate determination of 35S. For application of the technique where many of the most important atmospheric chemical processes are examined, significant interferences arise and accurate analysis in small samples is not possible...
January 19, 2018: Analytical Chemistry
Shengrui Zhang, Guojun Chen, Yuanyuan Wang, Qin Wang, Yaogang Zhong, Xiaofeng Yang, Zheng Li, Hua Li
Vicinal dithiol-containing proteins (VDPs) play fundamental roles in intracellular redox homeostasis and are responsible for many diseases. In this work, we report a far-red fluorescence turn-on probe MCAs for VDPs exploiting the pKa shift of the imine functionality of the probe. MCAs is composed of a merocyanine Schiff base as the fluorescent reporter and a cyclic 1, 3, 2-dithiarsenolane as the specific ligand for VDPs. The imine pKa of MCAs is 4.8, and it exists predominantly in the Schiff base (SB) form at physiological pH...
January 19, 2018: Analytical Chemistry
Carla S Santos, Renata Bannitz-Fernandes, Alex S Lima, Carlos A Tairum, Iran Malavazi, Luis Eduardo S Netto, Mauro Bertotti
In vivo studies on the degradation of exogenous hydrogen peroxide (H2O2) in the microenvironment of Aspergillus fumigatus fungus were performed by using an integrated Pt microelectrode. Three A. fumigatus strains were used to confirm the role of the cytosolic protein Prx1 on the defense mechanism of this microorganism: a wild-type strain, capable to express the protein Prx1; a Δprx strain, whose gene prx1 was removed; and a complemented Δprx1::prx1+ strain derivatized from the Δprx and in which the gene prx1 was re-introduced...
January 18, 2018: Analytical Chemistry
Guang-Li Wang, Fang Yuan, Tiantian Gu, Yuming Dong, Qian Wang, Wei-Wei Zhao
Herein we report a general and novel strategy for high-throughput photoelectrochemical (PEC) enzymatic bioanalysis on the basis of enzyme-initiated quinone-chitosan conjugation chemistry (QCCC). Specifically, the strategy was illustrated by using a model quinones-generating oxidase of tyrosinase (Tyr) to catalytically produce 1,2-bezoquinone or its derivative, which can easily and selectively be conjugated onto the surface of the chitosan deposited PbS/NiO/FTO photocathode via the QCCC. Upon illumination, the covalently attached quinones could act as electron acceptors of PbS quantum dots (QDs), improving the photocurrent generation and thus allowing the elegant probing of Tyr activity...
January 18, 2018: Analytical Chemistry
Erica Brunelle, Crystal Huynh, Eden Alin, Morgan Eldridge, Anh Minh Le, Lenka Halámková, Jan Halámek
No abstract text is available yet for this article.
January 18, 2018: Analytical Chemistry
Yuanshu Zhou, Masaki Saito, Takafumi Miyamoto, Pavel Novak, Andrew I Shevchuk, Yuri E Korchev, Takeshi Fukuma, Yasufumi Takahashi
Primary cilia are hair-like sensory organelles whose dimensions and location vary with cell type and culture condition. Herein, we employed scanning ion conductance microscopy (SICM) to visualize the topography of primary cilia from different cell types. By combining SICM with fluorescence imaging, we successfully distinguished between surface cilia that project outward from the cell surface and subsurface cilia that are trapped below it. The nanoscale structure of the ciliary pocket, which cannot be easily identified using a confocal fluorescence microscope, was observed in SICM images...
January 18, 2018: Analytical Chemistry
Mingling Dong, Wenshu Zheng, Yiping Chen, Bei Ran, Zhiyong Qian, Xingyu Jiang
Conventional magnetic sensors usually employ Fe-based magnetic materials as signal probes. In this work, we find that Cu(II) is also a useful longitudinal relaxation time (T1) signal-based magnetic probe. We adopt bathocuproinedisulfonic acid disodium salt hydrate (BCS) to chelate Cu(I) and form a stable Cu(I)-BCS complex in aqueous solution, and find the significant difference in T1 value of water protons between Cu(II) aqueous solution and Cu(I)-BCS complex aqueous solution. Redox reaction can convert Cu(II) to Cu(I) followed by the complexation of BCS, which results in apparent change of T1 that can serve as magnetic signal readout, which is the basis of this Cu-T1 sensor...
January 18, 2018: Analytical Chemistry
Prabhat K Upadhyay, Sreekar B Marpu, Erin N Benton, Corshai L Williams, Ameya Telang, Mohammad A Omary
We report a phosphorescent chemosensor based on a trinuclear Au(I) pyrazolate complex or [Au(3-CH3,5-COOH)Pz]3, (aka Au3Pz3) stabilized in aqueous chitosan (CS) polymer media. Au3Pz3 is synthesized in situ within aqueous CS media at pH ~ 6.5 and room temperature (RT). Au3Pz3 exhibits strong red emission (λmax ~690 nm) in such solutions. The Au3Pz3 emission is found to be sensitive to sub-ppm/nM levels of silver ions. On addition of silver salt to Au3Pz3/CS aqueous media, a bright-green emissive adduct (Au3Pz3/Ag+) with peak maximum within 475-515 nm is developed...
January 17, 2018: Analytical Chemistry
Rachel A Harris, Jody C May, Craig A Stinson, Yu Xia, John A McLean
The increasing focus on lipid metabolism has revealed a need for analytical techniques capable of structurally characterizing lipids with a high degree of specificity. Lipids can exist as any one of a large number of double bond positional isomers, which are indistinguishable by single-stage mass spectrometry alone. Ozonolysis reactions coupled to mass spectrometry have previously been demonstrated as a means for localizing double bonds in unsaturated lipids. Here we describe an online, solution-phase reactor using ozone produced via a low-pressure mercury lamp, which generates aldehyde products diagnostic of cleavage at a particular double bond position...
January 17, 2018: Analytical Chemistry
Nicolas Cassar, Weiyi Tang, Hans Gabathuler, Kuan Huang
Because of the difficulty in resolving the large variability of N2 fixation with current methods which rely on discrete sampling, the development of new methods for high resolution measurements is highly desirable. We present a new method for high-frequency measurements of aquatic N2 fixation by continuous flow-through incubations and spectral monitoring of the acetylene (C2H2, a substrate analog for N2) reduction to ethylene (C2H4). In this method, named "Flow-through incubation Acetylene Reduction Assays by Cavity ring-down laser Absorption Spectros-copy" (FARACAS), dissolved C2H2 is continuously admixed with seawater upstream of a continuous-flow stirred-tank reactor (CFSR) in which C2H2 reduction takes place...
January 17, 2018: Analytical Chemistry
Jiawang Ding, Nana Yu, Xuedong Wang, Wei Qin
A polymeric membrane ion-selective electrode (ISE) is typically designed for determination of one specific ion using conventional method. In this work, we demonstrate a simple, versatile and sensitive platform for simultaneous detection of two molecules with a single ISE. Under a series of periodic galvanostatic polarization, a solid-contact ISE without ion exchanger properties under zero-current conditions has been successfully used for simultaneous detection of two opposite charged ions with high sensitivity, good selectivity and fast reversibility...
January 17, 2018: Analytical Chemistry
Thierry Nicolas Jean Fouquet, Takaya Satoh, Hiroaki Sato
Its recent adaptation to low-resolution mass spectra of polymers using fractional base units raises the question of the minimal resolution needed for a Kendrick mass defect (KMD) analysis. Intuiting an oligomeric resolution since the mass of a repeat unit is the sole value to be known, it is challenged by the relative failure of the KMD plots computed from an isotopically resolved MALDI-TOF mass spectrum to display clear alignments in the high mass range. Another procedure based on the remainders of Kendrick mass (RKMs) overcomes this pitfall with oligomers perfectly aligned in a new RKM plot...
January 16, 2018: Analytical Chemistry
Ting Zhou, Teng Luo, Jun Song, Junle Qu
The design of highly efficient drug carriers, and the development of appropriate techniques to monitor their mechanism of action and therapeutic effect, are both critical for improving chemotherapy. Herein, a polymeric nanoparticle, PAH-Cit/DOX, was synthesized and used as a nano-drug system for the efficient delivery and pH-responsive release of doxorubicin (DOX) into cancer cells. The PAH-Cit/DOX nanoparticles were stable at physiological pH, but effectively released DOX under weakly acidic conditions. The release efficiency was 90...
January 16, 2018: Analytical Chemistry
Nicholas I Brodie, Romain Huguet, Terry Zhang, Rosa Viner, Vlad Zabrouskov, Jingxi Pan, Evgeniy V Petrotchenko, Christoph H Borchers
Top-down hydrogen-deuterium exchange (HDX) analysis using electron capture or transfer dissociation Fourier transform mass spectrometry is a powerful method for the analysis of secondary structure of proteins in solution. The resolution of the method is a function of the extensive fragmentation of backbone bonds in the proteins. While fragmentation is usually extensive near the N- and C-termini, electron capture (ECD) or electron transfer dissociation (ETD) fragmentation methods sometimes lack good coverage of certain regions of the protein - most often in the middle of the sequence...
January 16, 2018: Analytical Chemistry
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