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Analytical Chemistry

Wupeng Gan, Yin Gu, Junping Han, Caixia Li, Jing Sun, Peng Liu
Plastic microfluidic devices with embedded chitosan-modified Fusion 5 filter paper (unmodified one purchased from GE Healthcare) have been successfully developed for DNA extraction and concentration, utilizing two different mechanisms for DNA capture: the physical entanglement of long-chain DNA molecules with the fiber matrix of the filter paper and the electrostatic adsorption of DNA to the chitosan-modified filter fibers. This new method not only provided a high DNA extraction efficiency at a pH of 5 by synergistically combining these two capture mechanisms together, but also resisted the elution of DNA from filters at a pH >8 due to the entanglement of DNA with fibers...
February 23, 2017: Analytical Chemistry
Erica Megumi Kataoka, Rui Cesar Murer, Jandyson Machado Santos, Rogerio Mesquita de Carvalho, Marcos Nogueira Eberlin, Fabio Augusto, Ronei Jesus Poppi, Angelo Luiz Gobbi, Leandro Wang Hantao
In this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. Such platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration using proposed approach. This 3D-printed μSPE device was applied to challenging matrices in oil & gas industry, such as crude oil and oil-brine emulsions. Case studies investigated important limitations of non-silicon and non-glass microchips, namely, resistance to nonpolar solvents and conservation of sample integrity...
February 23, 2017: Analytical Chemistry
Qi Li, Rongxin Fu, Junqi Zhang, Ruliang Wang, Jiancheng Ye, Ning Xue, Xue Lin, Ya Su, Wupeng Gan, Ying Lu, Guoliang Huang
White light interference is used as a label-free method to detect nanoscale changes on surfaces. However, the signal-to-noise ratio of the white light interference method is very low, thus resulting in inaccurate results. In this paper, we report a corrected label-free method based on hyperspectral interferometry to overcome the shortcoming of the white light interference method. A platform based on hyperspectral interferometry was established, and a DNA hybridization microarray was constructed to quantitate thickness variation of molecules on a solid surface...
February 23, 2017: Analytical Chemistry
Jeffrey J Chalmers, Xiaoxia Jin, Andre Francis Palmer, Peter Amaya, Mark H Yazer, Lee R Moore, Kyoung-Joo Park, X Jeff Pan, Maciej Zborowski
The magnetic characteristics of hemoglobin (Hb) changes with the binding of dioxygen (O2) to the heme prosthetic groups of the globin chains: from paramagnetic ferrous Hb to diamagnetic ferrous oxyhemoglobin (oxyHb) with reversibly bound O2, or paramagnetic ferric methemoglobin (metHb). When multiplied over the number of Hb molecules in a red blood cell (RBC), the effect is detectable through motion analysis of RBCs in a high magnetic field and gradient. This motion is referred to as magnetophoretic mobility which can be conveniently expressed as a fraction of the cell sedimentation coefficient...
February 23, 2017: Analytical Chemistry
Vanousheh Rahemi, Nasrin Sarmadian, Willemien Anaf, Koen Janssens, Dirk Lamoen, Bart Partoens, Karolien De Wael
Chrome yellow refers to a group of synthetic inorganic pigments that became popular as an artist's material from the second quarter of the 19th century. The color of the pigment, in which the chromate ion acts as a chromophore, is related to its chemical composition (PbCr1-xSxO4, with 0≤x≤0.8) and crystalline structure (monoclinic/orthorhombic). Their shades range from the yellow-orange to the paler yellow tones with increasing sulfate amount. These pigments show remarkable signs of degradation after limited time periods...
February 23, 2017: Analytical Chemistry
Mingmin Li, Jin Li, Huixia Di, Huiqiao Liu, Dingbin Liu
Controlling the electromagnetic hot-spot generation is essential for surface-enhanced Raman scattering (SERS) assays. Current hot spot-based SERS assays have been extensively studied in solutions or on substrates. However, probing biospecies by controlling the hot-spot assembly in living systems has not been demonstrated thus far. Herein, we report a background-free SERS probe for imag-ing pyrophosphate (PPi), a biochemically significant anion, in living cells. Intracellular PPi is able to induce the nanoparticle dimeri-zation, thus creating an intense electromagnetic hot spot and dramatically enhancing the signal of the Raman reporters residing in the hot spot...
February 23, 2017: Analytical Chemistry
Kayleigh L Arthur, Matthew A Turner, James C Reynolds, Colin S Creaser
Full scan field asymmetric waveform ion mobility spectrometry (FAIMS) combined with liquid chromatography and mass spectrometry (LC-FAIMS-MS) is shown to enhance peak capacity for omics applications. A miniaturized FAIMS device capable of rapid compensation field scanning has been incorporated into an ultra-high performance liquid chromatography (UHPLC) and time-of-flight (TOF) mass spectrometry analysis, allowing the acquisition of full scan FAIMS and MS nested data sets within the timescale of a UHPLC peak...
February 23, 2017: Analytical Chemistry
Zachary J Barton, Joaquín Rodríguez-López
Scanning electrochemical microscopy (SECM) is a rising technique for the study of energy storage materials. Hg-based probes allow the extension of SECM investigations to ionic processes, but the risk of irreversible Hg amalgam saturation limits their operation to rapid timescales and dilute analyte solutions. Here, we report a novel fabrication protocol for Hg disc-well ultramicroelectrodes (UMEs), which retain access to stripping information but are less susceptible to amalgam saturation than traditional Hg sphere-caps or thin-films...
February 23, 2017: Analytical Chemistry
Zachary J Barton, Joaquín Rodríguez-López
We report a method of precisely positioning a Hg-based ultramicroelectrode (UME) for scanning electrochemical microscopy (SECM) investigations of any substrate. Hg-based probes are capable of performing amalgamation reactions with metal cations, which avoid unwanted side reactions and positive feedback mechanisms that can prove problematic for traditional probe positioning methods. However, prolonged collection of ions eventually leads to saturation of the amalgam accompanied by irreversible loss of Hg. In order to obtain negative feedback positioning control without risking damage to the SECM probe, we implement cyclic voltammetry probe approach surfaces (CV-PASs), consisting of CVs performed between incremental motor movements...
February 23, 2017: Analytical Chemistry
Jonathan V Sweedler
No abstract text is available yet for this article.
February 23, 2017: Analytical Chemistry
Raquel Sanchez, Burkhard Horstkotte, Katerina Fikarova, Hana Sklenářová, Salvador Maestre, Manuel Miró, José Luis Todoli
A proof of concept study involving the on-line coupling of automatic dispersive liquid-liquid microextraction (DLLME) to ICP OES with direct introduction and analysis of the organic extract is herein reported for the first time. The flow-based analyzer features a Lab-In-Syringe (LIS) setup with an integrated stirring system, a Meinhard® nebulizer in combination with a heated single-pass spray chamber, and a rotary injection valve, used as on-line interface between the microextraction system and the detection instrument...
February 23, 2017: Analytical Chemistry
Xinyuan He, Yanhui Xu, Wen Shi, Huimin Ma
An ultrasensitive ratiometric fluorescent probe (CVN) has been designed and synthesized by incorporating alanine into the cresyl violet fluorophore. The probe shows ratiometric fluorescence response toward aminopeptidase N (APN) through the increase of fluorescent intensity ratio of 626/575 nm. The sensitivity of the probe is ultrahigh with a detection limit of 33 pg/mL, which can quantify the contents of APN in 500-fold diluted human urine samples. Furthermore, by using ratiometric fluorescence imaging, the probe reveals significantly higher contents of APN in HepG2 cells than those in LO2 cells, which has been further used to distinguish these two types of cells in mixed cocultures...
February 23, 2017: Analytical Chemistry
Lei Wu, Shu-Hou Yang, Hao Xiong, Jia-Qian Yang, Jun Guo, Wen-Chao Yang, Guang-Fu Yang
We report herein a non-peptide-based small molecule probe for fluorogenic and chromogenic detection of chymotrypsin, and the primary application. This probe was rationally designed by mimicking the peptide substrate and optimized by adjusting the recognization group. The refined probe 2 exhibits good specificity toward chymotrypsin, producing about 25-fold higher enhancement in both the fluorescence intensity and absorbance upon the catalysis by chymotrypsin. Compared with the most widely used peptide substrate (AMC-FPAA-Suc) of chymotrypsin, probe 2 shows about 5-fold higher binding affinity, and comparable catalytical efficiency against chymotrypsin...
February 23, 2017: Analytical Chemistry
Chengyi Xiong, Wenbin Liang, Yingning Zheng, Ying Zhuo, Yaqin Chai, Ruo Yuan
Here, an ultrasensitive "off-on" electrochemiluminescence (ECL) biosensor was proposed for the determination of telomerase activity by using a self-enhanced ruthenium polyethylenimine (Ru-PEI) complex doped zeolitic imidazolate framework-8 (Ru-PEI@ZIF-8) with high ECL efficiency as an ECL indicator and an enzyme-assisted DNA cycle amplification strategy. The Ru-PEI@ZIF-8 nanocomposites were synthesized by self-enhanced Ru-PEI complex doping during the growth of zeolitic imidazolate framework-8 (ZIF-8), which presented high ECL efficiency and excellent stability...
February 23, 2017: Analytical Chemistry
Sei Hyun Yang, Doojin Lee, Jae Ryoun Youn, Young Seok Song
Particles in a viscoelastic fluid are typically focused at the center and four corners of a rectangular channel due to the combination of fluid elasticity and inertia forces. In this study, we observe the transition between single-line and multiple-line particle focusing in a microfluidic device induced by the synergetic effect of inertia and viscoelasticity. The elastic and inertial forces acting on suspended particles are manipulated by controlling the concentration of dilute polymer solution and the flow rate of a fluid...
February 22, 2017: Analytical Chemistry
Chunhong Zheng, Xiannian Zhang, Chunmei Li, Yuhong Pang, Yanyi Huang
Hydrodynamic flow is an essential stimulus in many cellular functions, regulating many mechanical sensitive pathways and closely associating with human health status and diseases. The flow pattern of blood in vessels is the key factor in causing atherosclerosis. Hemodynamics has great effect on endothelial cells' gene expression and biological functions. There are various tools that can be used for studying flow-induced cellular responses but most of them are either bulky or lack of precise controllability...
February 22, 2017: Analytical Chemistry
Yan Wu, Fubing Xiao, Zhaoyang Wu, Ruqin Yu
A novel aptasensor platform has been developed for quantitative detection of adenosine triphosphate (ATP) based on a ratiometric surface-enhanced Raman scattering (SERS) strategy. The thiolated 3'-Rox-labeled complementary DNA (cDNA) is first immobilized on the gold nanoparticle (AuNP) surface and then hybridizes with the 3'-Cy5-labeled ATP-binding aptamer probe (Cy5-aptamer) to form a rigid double-stranded DNA (dsDNA), in which the Cy5 and Rox Raman labels are used to produce the ratiometric Raman signals...
February 22, 2017: Analytical Chemistry
Ryo Nakabayashi, Kei Hashimoto, Kiminori Toyooka, Kazuki Saito
Streamlining the processes that reveal heteroatom-containing metabolites and their biosynthetic genes is essential in integrated metabolomics studies. These metabolites are especially targeted for their potential pharmaceutical activities. By using a Fourier-transform ion cyclotron resonance-mass spectrometry (FTICR-MS) instrument, we provide top-down targeted metabolomic analyses using ultrahigh-resolution liquid chromatography-mass spectrometry (LC-MS), high-resolution matrix-assisted laser desorption/ionization (MALDI), and high-resolution imaging mass spectrometry (IMS) with (15)N labeling of nitrogen-containing metabolites...
February 22, 2017: Analytical Chemistry
Jaclyn A Adkins, Katherine Boehle, Colin Friend, Briana Chamberlain, Bledar Bisha, Charles S Henry
The development of transparency-based electrochemical and paper-based colorimetric analytic detection platforms is presented as complimentary methods for food and waterborne bacteria detection from a single assay. Escherichia coli and Enterococcus species, both indicators of fecal contamination, were detected using substrates specific to enzymes produced by each species. β-galactosidase (β-gal) and β-glucosidase (β-gluco) are both produced by E. coli, while β-glucosidase (β-gluco) is produced by Enterococcus spp...
February 22, 2017: Analytical Chemistry
Brian C Defelice, Sajjan Singh Mehta, Stephanie Samra, Tomas Cajka, Benjamin Wancewicz, Johannes F Fahrmann, Oliver Fiehn
Untargeted metabolomics by liquid chromatography-mass spectrometry generates data rich chromatograms in form of m/z-retention time features. Managing such datasets is a bottleneck. Many popular data processing tools, including XCMS-online and MZmine2, yield numerous false positive peak detections. Flagging and removing such false peaks manually is a time consuming task and prone to human error. We present a web application, MS Feature List Optimizer (MS-FLO), to improve the quality of feature lists after initial processing to expedite the process of data curation...
February 22, 2017: Analytical Chemistry
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