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Analytical Methods: Advancing Methods and Applications

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https://www.readbyqxmd.com/read/27812369/the-performance-of-single-and-multi-collector-icp-ms-instruments-for-fast-and-reliable-34-s-32-s-isotope-ratio-measurements
#1
Ondrej Hanousek, Marion Brunner, Daniel Pröfrock, Johanna Irrgeher, Thomas Prohaska
The performance and validation characteristics of different single collector inductively coupled plasma mass spectrometers based on different technical principles (ICP-SFMS, ICP-QMS in reaction and collision modes, and ICP-MS/MS) were evaluated in comparison to the performance of MC ICP-MS for fast and reliable S isotope ratio measurements. The validation included the determination of LOD, BEC, measurement repeatability, within-lab reproducibility and deviation from certified values as well as a study on instrumental isotopic fractionation (IIF) and the calculation of the combined standard measurement uncertainty...
November 14, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27617038/3d-printed-microfluidic-devices-fabrication-advantages-and-limitations-a-mini-review
#2
Chengpeng Chen, Benjamin T Mehl, Akash S Munshi, Alexandra D Townsend, Dana M Spence, R Scott Martin
A mini-review with 79 references. In this review, the most recent trends in 3D-printed microfluidic devices are discussed. In addition, a focus is given to the fabrication aspects of these devices, with the supplemental information containing detailed instructions for designing a variety of structures including: a microfluidic channel, threads to accommodate commercial fluidic fittings, a flow splitter; a well plate, a mold for PDMS channel casting; and how to combine multiple designs into a single device. The advantages and limitations of 3D-printed microfluidic devices are thoroughly discussed, as are some future directions for the field...
August 21, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27574530/detection-and-identification-of-sugar-alcohol-sweeteners-by-ion-mobility-spectrometry
#3
Christopher A Browne, Thomas P Forbes, Edward Sisco
The rapid and sensitive detection of sugar alcohol sweeteners was demonstrated using ion mobility spectrometry (IMS). IMS provides a valuable alternative in sensitivity, cost, and analysis speed between the lengthy gold-standard liquid chromatography-mass spectrometry (LC-MS) technique and rapid point-of-measurement disposable colorimetric sensors, for the Food and Nutrition industry's quality control and other "foodomics" area needs. The IMS response, characteristic signatures, and limits of detection for erythritol, pentaerythritol, xylitol, inositol, sorbitol, mannitol, and maltitol were evaluated using precise inkjet printed samples...
July 28, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27818712/integrated-electrodes-and-electrospray-emitter-for-polymer-microfluidic-nanospray-ms-interface
#4
Anna V Forzano, Vedada Becirovic, R Scott Martin, James L Edwards
Interfacing of microfluidic devices to mass spectrometry has challenges including dilution from sheath liquid junctions, fragile electrodes, and excessive dead volumes which prevent optimum performance and common use. The goal of this work is to develop a stable nanospray chip-MS interface that contains easily integrated electrodes and an embedded capillary emitter to mitigate current chip-MS problems. This system uses a hybrid polystyrene-poly(dimethylsiloxane) (PS-PDMS) microfluidic platform with an embedded electrode and integrated capillary emitter used as the nanospray interface...
July 7, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27695531/quantitative-determination-of-betamethasone-sodium-phosphate-and-betamethasone-dipropionate-in-human-plasma-by-uplc-ms-ms-and-a-bioequivalence-study
#5
Man-Yun Chen, Yong-Jun Tang, Yi-Cheng Wang, Chong-Zhi Wang, Chun-Su Yuan, Yao Chen, Zhi-Rong Tan, Wei-Hua Huang, Hong-Hao Zhou
The compound medicine of betamethasone sodium phosphate (BSP) and betamethasone dipropionate (BDP) is widely used for diverse glucocorticoid-sensitive acute and chronic diseases such as asthma, rheumatoid arthritis and systemic lupus erythematosus. It will be useful and beneficial to validate sensitive method for the determination of BSP, BDP and their metabolites for their pharmacokinetic study. Hereby, an ultra-high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been validated for the determination of BSP, BDP and their metabolites betamethasone (BOH), betamethasone 17-monodipropionate (B17P) and betamethasone 21-monodipropionate (B21P) in human plasma...
May 7, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27482292/a-label-free-sirtuin-1-assay-based-on-droplet-electrospray-ionization-mass-spectrometry
#6
Shuwen Sun, Benjamin C Buer, E Neil G Marsh, Robert T Kennedy
Sirtuin 1(SIRT1) is a NAD(+)-dependent deacetylase which has been implicated in age-related diseases such as cancer, Alzheimer's disease, type 2 diabetes, and vascular diseases. SIRT1 modulators are of interest for their potential therapeutic use and potential as chemical probes to study the role of SIRT1. Fluorescence-based assays used to identify SIRT1 activators have been shown to have artifacts related to the fluorophore substrates used in the assays. Such problems highlight the potential utility of a label-free high throughput screening (HTS) strategy...
May 7, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27688816/a-capillary-electrophoresis-electrospray-ionization-mass-spectrometry-method-using-a-borate-background-electrolyte-for-the-fingerprinting-analysis-of-flavonoids-in-ginkgo-biloba-herbal-supplements
#7
Ryan T Johnson, Craig E Lunte
A laboratory-built sheath liquid capillary electrophoresis-mass spectrometry interface was used to develop a qualitative method for fingerprinting analysis of 14 structurally similar flavones, flavonols, flavonones, and several representative glycosides in plant samples. The migration order of the flavonoids was dependent on a the number of hydroxyl groups present on the flavonoid B-ring, extent of conjugation, number of glycosidic functionalities, and ability of the flavonoid to form stable borate complexes with the background electrolyte...
April 28, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27909462/difluoroboron-%C3%AE-diketonate-materials-with-long-lived-phosphorescence-enable-lifetime-based-oxygen-imaging-with-a-portable-cost-effective-camera
#8
Alexander S Mathew, Christopher A DeRosa, James N Demas, Cassandra L Fraser
Lifetime-based oxygen imaging is useful in many biological applications but instrumentation can be stationary, expensive, and complex. Herein, we present a portable, cost effective, simple alternative with high spatiotemporal resolution that uses a complementary metal oxide silicon (CMOS) camera to measure oxygen sensitive lifetimes on the millisecond scale. We demonstrate its compatibility with difluoroboron β-diketonate poly(lactic acid) (BF2bdkPLA) polymers which are nontoxic and exhibit long-lived oxygen sensitive phosphorescence...
April 21, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27335585/detection-of-low-molecular-weight-adulterants-in-beverages-by-direct-analysis-in-real-time-mass-spectrometry
#9
Edward Sisco, Jeffrey Dake
Direct Analysis in Real Time Mass Spectrometry (DART-MS) has been used to detect the presence of non-narcotic adulterants in beverages. The non-narcotic adulterants that were examined in this work incorporated a number low molecular weight alcohols, acetone, ammonium hydroxide, and sodium hypochlorite. Analysis of the adulterants was completed by pipetting 1 µL deposits onto glass microcapillaries along with an appropriate dopant species followed by introduction into the DART gas stream. It was found that detection of these compounds in the complex matrices of common beverages (soda, energy drinks, etc...
April 14, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26997980/characterization-of-polyamidoamino-pamam-dendrimers-using-in-line-reversed-phase-lc-electrospray-ionization-mass-spectrometry
#10
John R Lloyd, P Suresh Jayasekara, Kenneth A Jacobson
Generation 3 (G3) PAMAM dendrimers are symmetrical, highly branched polymers widely reported in the scientific literature as therapeutic agents themselves or as carrier scaffolds for various therapeutic agents. A large number of analytical techniques have been applied to study PAMAM dendrimers, but one that has been missing is in-line reversed phase LC electrospray ionization mass spectrometry (RP/LC/ESI/MS). To translate PAMAM dendrimers into therapeutic agents, a better understanding of their purity, stability and structure is required, and in-line RP/LC/ESI/MS is widely applied to all three of these analytical questions...
January 14, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/27482293/analysis-of-trace-amounts-of-adulterants-found-in-powders-supplements-utilizing-raman-spectroscopy-coupled-to-direct-analyte-probed-nanoextraction-nanospray-ionization-mass-spectrometry
#11
Chinyere N Nnaji, Phillip M Mach, Jason S Acheampong, Travis M Falconer, Guido F Verbeck
In the United States, all food products have to be regulated to inform the consumers of the ingredients contained within. Some ingredients are not included on the label and yet are still found in the products. Presented is a Raman imaging technique for rapid, nondestructive, and spatially relevant localization of adulterants in powders. Raman spectroscopy followed by direct analyte-probed nanoextraction coupled to nanospray ionization-mass spectrometry allows rapid determination of the presence of each adulterant, leading to positive identifications such as melamine...
2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26744605/in-vitro-biophysical-microspectroscopic-and-cytotoxic-evaluation-of-metastatic-and-non-metastatic-cancer-cells-in-responses-to-anti-cancer-drug
#12
Qifei Li, Lifu Xiao, Sitaram Harihar, Danny R Welch, Elizabeth Vargis, Anhong Zhou
The Breast Cancer Metastasis Suppressor 1 (BRMS1) is a nucleo-cytoplasmic protein that suppresses cancer metastasis without affecting the growth of the primary tumor. Previous work has shown that it decreases the expression of protein mediators involved in chemoresistance. This study measured the biomechanical and biochemical changes in BRMS1 expression and the responses of BRMS1 to drug treatments on cancer cells in vitro. The results show that BRMS1 expression affects biomechanical properties by decreasing the Young's modulus and adhesion force of breast cancer cells after doxorubicin (DOX) exposure...
December 21, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26528375/single-cell-migration-as-studied-by-scanning-electrochemical-microscopy
#13
J Ganesh Ummadi, Vrushali S Joshi, Priya R Gupta, Arup K Indra, Dipankar Koley
Scanning electrochemical microscopy (SECM) was used to study the migration of single live head and neck cancer cells (SCC25). The newly developed graphite paste ultramicroelectrode (UME) showed significantly less fouling in comparison to a 10 μm Pt-UME and thus could be used to monitor and track the migration pattern of a single cell. We also used SECM probe scan curves to measure the morphology (height and diameter) of a single live cancer cell during cellular migration and determined these dimensions to be 11 ± 4 μm and 40 ± 10 μm, respectively...
October 21, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26528374/magnetically-actuated-bead-enhanced-silicon-photonic-immunosensor
#14
Enrique Valera, Melinda S McClellan, Ryan C Bailey
Magnetic actuation has been introduced to an optical immunosensor technology resulting in improvements in both rapidity and limit of detection for an assay quantitating low concentrations of a representative protein biomarker. For purposes of demonstration, an assay was designed for monocyte chemotactic protein 1 (MCP-1), a small cytokine which regulates migration and infiltration of monocytes and macrophages, and is an emerging biomarker for several diseases. The immunosensor is based on arrays of highly multiplexed silicon photonic microring resonators...
October 21, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26527562/sensitive-detection-of-cardiac-biomarkers-using-a-magnetic-microbead-immunoassay
#15
Christine F Woolley, Mark A Hayes
To achieve improved sensitivity in cardiac biomarker detection, a batch incubation magnetic microbead immunoassay was developed and tested on three separate human protein targets: myoglobin, heart-type fatty acid binding protein, and cardiac troponin I. A sandwich immunoassay was performed in a simple micro-centrifuge tube allowing full dispersal of the solid capture surface during incubations. Following magnetic bead capture and wash steps, samples were analyzed in the presence of a manipulated magnetic field utilizing a modified microscope slide and fluorescent inverted microscope to collect video data files...
October 21, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26523155/development-of-an-automated-on-chip-bead-based-elisa-platform
#16
Jennifer Campbell, Nira Pollock, Andre Sharon, Alexis F Sauer-Budge
We present a lab-on-a-chip and associated instrument for heterogeneous enzyme-linked immunosorbent assay (ELISA)-based detection of proteins from liquid samples. The system performs all necessary ELISA steps (starting from antigen incubation) in a quarter of the time required for corresponding plate-based protocols. We have previously described the instrument, which automates fluidic control via remote valve switching and detects fluorescence from reacted substrate, for use in a molecular diagnostics application...
October 7, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26604989/chemometric-analysis-of-maldi-mass-spectrometric-images-of-three-dimensional-cell-culture-systems
#17
Eric M Weaver, Amanda B Hummon, Richard B Keithley
As imaging mass spectrometry (IMS) has grown in popularity in recent years, the applications of this technique have become increasingly diverse. Currently there is a need for sophisticated data processing strategies that maximize the information gained from large IMS data sets. Traditional two-dimensional heat maps of single ions generated in IMS experiments lack analytical detail, yet manual analysis of multiple peaks across hundreds of pixels within an entire image is time-consuming, tedious and subjective...
September 7, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26604988/a-strategy-for-minimizing-background-signal-in-autoinductive-signal-amplification-reactions-for-point-of-need-assays
#18
Adam D Brooks, Kimy Yeung, Gregory G Lewis, Scott T Phillips
Rapid point-of-need assays are used to detect abundant biomarkers. The development of in situ signal amplification reactions could extend these assays to screening and triaging of patients for trace levels of biomarkers, even in resource-limited settings. We, and others, have developed small molecule-based in situ signal amplification reactions that eventually may be useful in this context. Herein we describe a design strategy for minimizing background signal that may occur in the absence of the target analyte, thus moving this in situ signal amplification approach one step closer to practical applications...
September 7, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26366207/quantifying-aptamer-protein-binding-via-thermofluorimetric-analysis
#19
Juan Hu, Joonyul Kim, Christopher J Easley
Effective aptamer-based protein assays require coupling to a quantitative reporter of aptamer-protein binding. Typically, this involves a direct optical or electrochemical readout of DNA hybridization or an amplification step coupled to the readout. However, method development is often hampered by the multiplicity of aptamer-target binding mechanisms, which can interfere with the hybridization step. As a simpler and more generalizable readout of aptamer-protein binding, we report that thermofluorimetric analysis (TFA) can be used to quantitatively assay protein levels...
September 7, 2015: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/26327927/electrochemical-nanoprobes-for-the-chemical-detection-of-neurotransmitters
#20
Mei Shen, Michelle L Colombo
Neurotransmitters, acting as chemical messengers, play an important role in neurotransmission, which governs many functional aspects of nervous system activity. Electrochemical probes have proven a very useful technique to study neurotransmission, especially to quantify and qualify neurotransmitters. With the emerging interests in probing neurotransmission at the level of single cells, single vesicles, as well as single synapses, probes that enable detection of neurotransmitters at the nanometer scale become vitally important...
September 7, 2015: Analytical Methods: Advancing Methods and Applications
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