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Analytical Chemistry

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https://www.readbyqxmd.com/read/28548845/a-new-analytical-framework-for-verification-of-biomarkers-of-exposure-to-chemicals-combining-human-biomonitoring-and-water-fingerprinting
#1
Luigi Lopardo, Andrew Cummins, Axel Rydevik, Barbara Kasprzyk-Hordern
Molecular epidemiology approaches in human biomonitoring are powerful tools that allow for verification of public exposure to chemical substances. Unfortunately, due to logistical difficulties and high cost, they tend to evaluate small study groups and as a result might not provide comprehensive large scale community-wide exposure data. Urban water fingerprinting provides a timely alternative to traditional approaches. It can revolutionise the human exposure studies as urban water represents collective community-wide exposure...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28548821/turning-nonspecific-interference-into-signal-amplification-covalent-biosensing-nanoassembly-enabled-by-metal-catalyzed-cross-coupling
#2
Hao Li, Fang Wang, Shenguang Ge, Haiyun Liu, Mei Yan, Jinghua Yu
In this work, a new method of protein detection in complicated samples is proposed. This method employs probe-target recognition to induce cross-linking among the probe, the target, and the nonspecific proteins in the complicated sample as a means to convert interference into effective signal amplification. This also eliminates the necessity of multistep signal amplification in a separate solution system. On the basis of this strategy, a simple and robust assay for the activity of serum cathepsin B is established...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28548491/deposition-of-a-sorbent-into-a-recession-on-a-solid-support-provides-a-new-mechanically-robust-solid-phase-micro-extraction-device
#3
Justen J Poole, Jonathan J Grandy, Miao Yu, Ezel Boyaci, German A Gomez Rios, Nathaly Reyes-Garcés, Barbara Bojko, Harmen Vander Heide, Janusz Pawliszyn
To date, solid-phase microextraction (SPME) fibers used for in-vivo bio-analysis can be too fragile and flexible, which limits suitability for direct tissue sampling. As a result, these devices often require a sheathing needle to pre-puncture robust sample matrices and protect the extraction phase from mechanical damage. To address this limitation, a new SPME device is herein presented which incorporates an extraction phase recessed into the body of a solid needle. This device requires no additional support or shielding during puncture events through protective tissue...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28548489/glycosaminoglycans-specific-cell-targeting-and-imaging-using-fluorescent-nanodiamonds-coated-with-viral-envelope-proteins
#4
Minh D Pham, Chandra Prakash Epperla, Chia-Lung Hsieh, Wen Chang, Huan-Cheng Chang
Understanding virus-host interactions is crucial for vaccine development. This study investigates such interactions using fluorescent nanodiamonds (FNDs) coated with vaccinia envelope proteins as the model system. To achieve this goal, we noncovalently conjugated 100-nm FND with A27(aa 21-84), a recombinant envelope protein of vaccinia virus, for glycosaminoglycans (GAGs)-specific targeting and imaging of living cells. Another recombinant protein A27(aa 33-84) that removes the GAGs-binding sequences was also used for comparison...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28548485/clinically-relevant-detection-of-streptococcus-pneumoniae-with-dna-antibody-nanostructures
#5
Jinping Wang, May Ching Leong, Eric Zhewei Leong, Win Sen Kuan, David T Leong
Streptococcus pneumoniae (SP) is a pathogenic bacterium and a major cause of community-acquired pneumonia that could be fatal if left untreated. Therefore, rapid and sensitive detection of SP is crucial to enable targeted treatment during SP infections. In this study, DNA tetrahedron (DNA TH) with a hollow structure is anchored on gold electrodes to construct an electrochemical immunosensor for rapid detection of pneumococcal surface protein A (PspA) peptide and SP lysate from synthetic and actual human samples...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28548482/simultaneous-separation-and-washing-of-non-magnetic-particles-in-an-inertial-ferrofluid-water-co-flow
#6
Qi Chen, Di Li, Jianhan Lin, Mao-Hua Wang, Xiangchun Xuan
Magnetic fluids (e.g., paramagnetic solutions and ferrofluids) have been increasingly used for label-free separation of non-magnetic particles in microfluidic devices. Their biocompatibility, however, becomes a concern in high-throughput or large-volume applications. One way to potentially resolve this issue is re-suspending the particles that are separated in a magnetic fluid immediately into a biocompatible buffer. We demonstrate herein the proof-of-principle of the first integration of negative magnetophoresis and inertial focusing for a simultaneous separation and washing of non-magnetic particles in co-flowing ferrofluid and water streams...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28520403/integrated-strategy-for-unknown-ei-ms-identification-using-quality-control-calibration-curve-multivariate-analysis-ei-ms-spectral-database-and-retention-index-prediction
#7
Teruko Matsuo, Hiroshi Tsugawa, Hiromi Miyagawa, Eiichiro Fukusaki
Compound identification using unknown electron ionization (EI) mass spectra in gas chromatography coupled with mass spectrometry (GC-MS) is challenging in untargeted metabolomics, natural product chemistry, or exposome research. While the total count of EI-MS records included in publicly or commercially available databases is over 900 000, efficient use of this huge database has not been achieved in metabolomics. Therefore, we proposed a "four-step" strategy for the identification of biologically significant metabolites using an integrated cheminformatics approach: (i) quality control calibration curve to reduce background noise, (ii) variable selection by hypothesis testing in principal component analysis for the efficient selection of target peaks, (iii) searching the EI-MS spectral database, and (iv) retention index (RI) filtering in combination with RI predictions...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28517930/middle-down-193-nm-ultraviolet-photodissociation-for-unambiguous-antibody-identification-and-its-implications-for-immunoproteomic-analysis
#8
Victoria C Cotham, Andrew P Horton, Jiwon Lee, George Georgiou, Jennifer S Brodbelt
Mass spectrometry (MS) has emerged as a powerful tool within the growing field of immunoproteomics, which aims to understand antibody-mediated immunity at the molecular-level based on the direct determination of serological antibody repertoire. To date, these methods have relied on the use of high-resolution bottom-up proteomic strategies that require effective sampling and characterization of low abundance peptides derived from the antigen-binding domains of polyclonal antibody mixtures. Herein, we describe a method that uses restricted Lys-C enzymatic digestion to increase the average mass of proteolytic IgG peptides (≥4...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28514136/highly-selective-volatile-organic-compounds-breath-analysis-using-a-broadly-tunable-vertical-external-cavity-surface-emitting-laser
#9
Béla Tuzson, Jana Jágerská, Herbert Looser, Manuel Graf, Ferdinand Felder, Matthias Fill, Luc Tappy, Lukas Emmenegger
A broadly tunable mid-infrared vertical-external-cavity surface-emitting laser (VECSEL) is employed in a direct absorption laser spectroscopic setup to measure breath acetone. The large wavelength coverage of more than 30 cm(-1) at 3.38 μm allows, in addition to acetone, the simultaneous measurement of isoprene, ethanol, methanol, methane, and water. Despite the severe spectral interferences from water and alcohols, an unambiguous determination of acetone is demonstrated with a precision of 13 ppbv that is achieved after 5 min averaging at typical breath mean acetone levels in synthetic gas samples mimicking human breath...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28510445/establishment-of-a-direct-injection-electron-ionization-mass-spectrometry-metabolomics-method-and-its-application-to-lichen-profiling
#10
Hisahiro Kai, Kaoru Kinoshita, Hiroshi Harada, Yoshihiro Uesawa, Akihiro Maeda, Ryuichiro Suzuki, Yoshihito Okada, Kunio Takahashi, Koji Matsuno
Direct-injection electron ionization-mass spectrometry (DI-EI-MS) is a multivariate analysis method useful for characterizing biological materials. We demonstrated the use of DI-EI-MS for metabolic profiling using several closely related lichen species: Cladonia krempelhuberi, C. gracilis, C. pseudogymnopoda, and C. ramulosa. The methodology involves conversion of total ion chromatograms to integrated chromatograms and assessment of reproducibility. The qualitative DI-EI-MS method was used to profile the major and/or minor constituents in extracts of lichen samples...
May 26, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541676/double-sweeping-highly-effective-sample-preconcentration-using-cationic-and-anionic-micelles-and-its-application-to-a-multiple-enzyme-activity-assay
#11
Ryota Sanuki, Kenji Sueyoshi, Tatsuro Endo, Hideaki Hisamoto
In conventional microfluidic bioassays, short optical pathlength and extremely small quantities of analytes sometimes can significantly reduce detectability. Various sample preconcentration techniques have been reported for improving the detectability of bioassays. In the present study, we developed a novel preconcentration technique, 'double sweeping', utilizing cationic and anionic micelles simultaneously. Microscopic observations demonstrated that double sweeping enabled a sample solution, which initially filled a capillary, to be focused into an extremely narrow band...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541670/metrics-to-evaluate-journals-scientists-and-science-we-are-not-there-yet
#12
Jonathan V Sweedler
No abstract text is available yet for this article.
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541664/prediction-of-collision-cross-section-values-for-small-molecules-application-to-pesticide-residue-analysis
#13
Lubertus Bijlsma, Richard Bade, Alberto Celma, Lauren Mullin, Gareth Cleland, Sara Stead, Felix Hernandez, Juan Vicente Sancho
The use of collision cross-section (CCS) values obtained by ion mobility high-resolution mass spectrometry has added a third dimension (alongside retention time and exact mass) to aid in the identification of compounds. However, its utility is limited by the number of experimental CCS values currently available. This work demonstrates the potential of artificial neural networks (ANNs) for the prediction of CCS values of pesticides. The predictor, based on eight software-chosen mo-lecular descriptors, was optimised using CCS values of 205 small molecules and validated using a set of 131 pesticides...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541659/multifunctional-screening-platform-for-the-highly-efficient-discovery-of-aptamers-with-high-affinity-and-specificity
#14
Shao-Li Hong, Ya-Tao Wan, Man Tang, Dai-Wen Pang, Zhi-Ling Zhang
Aptamers have attracted much attention as next generation of affinity reagents. Unfortunately, the selection efficiency remains a critical bottleneck for the widespread application of aptamers. Herein, to accelerate aptamers discovery, a multifunctional microfluidic selection platform was developed, on which the selection efficiency was greatly improved and high affinity and specificity aptamers were generated within two round selections. The multifunctional screening platform, precisely manipulating magnetic beads on micrometer scale, improved selection performance based on microfluidic continuous flow and enhanced the selection process control via in-situ monitoring and real-time evaluation...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541039/label-free-discrimination-of-rhizobial-bacteroids-and-mutants-by-single-cell-raman-microspectroscopy
#15
Jiabao Xu, Isabel Webb, Philip Poole, Wei E Huang
Symbiotic rhizobia in legume account for a large portion of nitrogen fixation in the biosphere. Nitrogen fixation is an energy-demanding process requiring tight control of metabolism and redox state. It is of great interest to understand the bacteroid differentiation process and the roles of energy storage molecules, such as glycogen and polyhydroxybutyrate (PHB), in maintaining the Rhizobium-legume symbioses. Traditional biochemical assays for checking phenotypic changes of mutants require a large volume of starting materials, which is difficult for unculturable, terminally differentiated bacteroids...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541036/non-invasive-diagnosis-of-high-grade-urothelial-carcinoma-in-urine-by-raman-spectral-imaging
#16
Hesham K Yosef, Sascha D Krauß, Tatjana Lechtonen, Hendrik Jütte, Andrea Tannapfel, Heiko Udo Käfferlein, Thomas Brüning, Florian Roghmann, Joachim Noldus, Axel Mosig, Samir F El-Mashtoly, Klaus Gerwert
The current gold standard for diagnosis of bladder cancer is cystoscopy, which is an invasive and painful for patients. Therefore, the non-invasive urine cytology is usually used in clinics as an adjunct to cystoscopy. However, it suffers from low sensitivity. Here, a novel non-invasive, label-free approach on urine is presented with high sensitivity. CARS imaging of urine sediments was used in the first step for fast preselection of urothelial cells, where, the high-grade urothelial cancer cells are characterized by a large nucleus to cytoplasm ratio...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541034/microfluidic-capillaric-circuit-for-rapid-and-facile-bacteria-detection
#17
Ayokunle Oluwafemi Olanrewaju, Andy Ng, Philippe Decorwin-Martin, Alessandra Robillard, David Juncker
Urinary tract infections (UTI) are one of the most common bacterial infections and would greatly benefit from a rapid point-of-care diagnostic test. Although significant progress has been made in developing microfluidic systems for nucleic acid and whole bacteria immunoassay tests, their practical application is limited by complex protocols, bulky peripherals, and slow operation. Here we present a microfluidic capillaric circuit (CC) optimized for rapid and automated detection of bacteria in urine. Molds for CCs were constructed using previously-established design rules, then 3D-printed and replicated into poly(dimethylsiloxane)...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541032/exosome-classification-by-pattern-analysis-of-surface-enhanced-raman-spectroscopy-data-for-lung-cancer-diagnosis
#18
Jaena Park, Miyeon Hwang, ByeongHyeon Choi, Hyesun Jeong, Jik-Han Jung, Hyun Koo Kim, Sunghoi Hong, Ji Ho Park, Yeonho Choi
Owing to the role of exosome as a cargo for intercellular communication, especially in cancer metastasis, the evidence has been consistently accumulated that exosomes can be used as a non-invasive indicator of cancer. Consequently, several studies applying exosome have been proposed for cancer diagnostic methods such as ELISA assay. However, it has been still challenging to get reliable results due to the requirement of a labeling process and high concentration of exosome. Here, we demonstrate a label-free and highly sensitive classification method of exosome by combining surface enhanced Raman scattering (SERS) and statistical pattern analysis...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28541030/pt-nanoparticle-collisions-detected-by-electrocatalytic-amplification-and-afm-imaging-np-collision-frequency-adsorption-and-random-distribution-at-an-ume-surface
#19
Cesar A Ortiz-Ledón, Cynthia G Zoski
We demonstrate good agreement between the theoretical and experimental collision frequency of individual Pt NPs undergoing collisions at a Au UME (5 µm radius) using electrocatalytic amplification provided by 15 mM hydrazine in 5 mM PB (pH7) over 100 to 300 s. DLS measurements demonstrated that Pt NP aggregation in this solution had the least impact on NP diffusion coefficient and concentration values, which are directly proportional to collision frequency. We show that the smaller, uniform current steps are indicative of NPs of metallic radii in agreement with those determined by TEM, with corresponding larger NP diffusion coefficient and concentration, in agreement with DLS results...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28540730/surface-confined-aqueous-reversible-addition-fragmentation-chain-transfer-scaraft-polymerization-method-for-preparation-of-coated-capillary-leads-to-over-10-000-peptides-identified-from-25-ng-hela-digest-by-using-capillary-zone-electrophoresis-tandem-mass-spectrometry
#20
Zhenbin Zhang, Elizabeth H Peuchen, Norman J Dovichi
A surface-confined aqueous reversible addition-fragmentation chain transfer (SCARAFT) polymerization method was developed to coat capillaries for use in capillary zone electrophoresis (CZE). SCARAFT polymerization primarily takes place on the inner surface of the capillary instead of in solution, which greatly improves the homogeneity of the coating. Capillaries treated with this coating produced an electroosmotic mobility of 2.8 ± 0.2 × 10-6 cm2·V 1·s-1 (N=3), which is roughly an order of magnitude lower than that of commercial linear polyacrylamide (LPA) coated capillaries...
May 25, 2017: Analytical Chemistry
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