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Analytical Methods: Advancing Methods and Applications

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https://www.readbyqxmd.com/read/29062391/metabolic-comparison-of-dorsal-versus-ventral-cells-directly-in-the-live-8-cell-frog-embryo-by-microprobe-single-cell-ce-esi-ms
#1
Rosemary M Onjiko, David O Plotnick, Sally A Moody, Peter Nemes
Single-cell mass spectrometry (MS) empowers the characterization of metabolomic changes as cells differentiate to different tissues during early embryogenesis. Using whole-cell dissection and capillary electrophoresis electrospray ionization (CE-ESI) MS, we recently uncovered metabolic cell-to-cell differences in the 8- and 16-cell embryo of the South African clawed frog (Xenopus laevis), raising the question whether metabolic cell heterogeneity is also detectable across the dorsal-ventral axis of the 8-cell embryo...
September 14, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29187865/a-novel-method-of-nicotine-quantification-in-electronic-cigarette-liquids-and-aerosols
#2
Mumiye A Ogunwale, Yizheng Chen, Whitney S Theis, Michael H Nantz, Daniel J Conklin, Xiao-An Fu
The electronic cigarette (e-cigarette) has emerged as popular electronic nicotine delivery devices (ENDs). However, the general safety and validity of e-cigarettes for nicotine delivery efficacy are still not well understood. This study developed a new method for efficient measurement of nicotine levels in both the liquids (e-liquids) used in e-cigarettes and the aerosols generated from the e-cigarettes. Protonation of the pyrrolidine nitrogen of nicotine molecules by addition of excess hydrochloric acid affords an aminium salt that is readily quantified by Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS)...
August 7, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28966665/si-traceable-determination-of-arsenic-species-in-kelp-thallus-laminariae
#3
Lee L Yu, Rachel C Stanoyevitch, Rolf Zeisler
A dietary supplement, kelp contains a significant amount of arsenic that is mostly arsenosugars. The determination of arsenosugars is difficult due to a lack of arsenosugar calibration standard, because arsenosugar compounds are not commercially available. This work reports the determination of arsenicals in a kelp extract with traceability to the International System of Units (SI). The hydrophilic fraction of arsenicals was reproducibly extracted from a candidate Standard Reference Material (SRM) 3232 Kelp Powder (Thallus Laminariae) in development at the National Institute of Standards and Technology (NIST)...
August 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28824713/recent-liquid-chromatographic-approaches-and-developments-for-the-separation-and-purification-of-carbohydrates
#4
Gabe Nagy, Tianyuan Peng, Nicola L B Pohl
Carbohydate purification remains a bottleneck in securing analytical standards from natural sources or by chemical or enzymatic synthesis. This review highlights the scope and remaining limitations of recent approaches and methods development in liquid chromatography for robust and higher-throughput carbohydrate separation and isolation.
June 28, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28690683/microchip-based-3d-cell-culture-using-polymer-nanofibers-generated-by-solution-blow-spinning
#5
Chengpeng Chen, Alexandra D Townsend, Scott A Sell, R Scott Martin
Polymer nano/micro fibers have found many applications including 3D cell culture and the creation of wound dressings. The fibers can be produced by a variety of techniques that include electrospinning, the primary disadvantage of which include the requirement for a high voltage supply (which may cause issues such as polymer denaturation) and lack of portability. More recently, solution blow spinning, where a high velocity sheath gas is used instead of high voltage, has been used to generate polymer fibers. In this work, we used blow spinning to create nano/microfibers for microchip-based 3D cell culture...
June 14, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28674558/analysis-of-stable-isotope-assisted-metabolomics-data-acquired-by-high-resolution-mass-spectrometry
#6
X Wei, P K Lorkiewicz, B Shi, J K Salabei, B G Hill, S Kim, C J McClain, X Zhang
Stable isotope assisted metabolomics (SIAM) uses stable isotope tracers to support studies of biochemical mechanisms. We report a suite of data analysis algorithms for automatic analysis of SIAM data acquired on a high resolution mass spectrometer. To increase the accuracy of isotopologue assignment, metabolites detected in the unlabeled samples were used as reference metabolites to generate possible isotopologue candidates for analysis of peaks detected in the labeled samples. An iterative linear regression model was developed to deconvolute the overlapping isotopic peaks of isotopologues present in a full MS spectrum, where the threshold for the weight factor was determined by a simulation study assuming different levels of Gaussian white noise contamination...
April 21, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29034007/microfluidic-iterative-mechanical-characteristics-imech-analyzer-for-single-cell-metastatic-identification
#7
Hesam Babahosseini, Jeannine S Strobl, Masoud Agah
This study describes the development of a microfluidic biosensor called the iterative mechanical characteristics (iMECH) analyzer which enables label-free biomechanical profiling of individual cells for distinction between metastatic and non-metastatic human mammary cell lines. Previous results have demonstrated that pulsed mechanical nanoindentation can modulate the biomechanics of cells resulting in distinctly different biomechanical responses in metastatic and non-metastatic cell lines. The iMECH analyzer aims to move this concept into a microfluidic, clinically more relevant platform...
February 7, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28286575/chiral-determination-of-3-4-methylenedioxypyrovalerone-enantiomers-in-rat-serum
#8
Michael D Hambuchen, Howard P Hendrickson, S Michael Owens
The emerging stimulant drug of abuse (3,4)-methylenedioxypyrovalerone [(R,S)-MDPV] is self-administered as a racemic mixture by intranasal, iv, oral, and smoking routes. The individual enantiomers are known to have widely different pharmacological effects, with (S)-MDPV showing much greater potency than (R)-MDPV in pharmacological testing. The goal of these studies was to develop and validate an analytical method for quantitation of (R)-MDPV, (S)-MDPV and (R,S)-MDPV in small volumes of rat serum using a chiral separation column and liquid chromatography-mass spectrometry...
January 28, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28217148/profiling-metals-in-cordyceps-sinensis-by-using-inductively-coupled-plasma-mass-spectrometry
#9
Xin Wei, Hankun Hu, Baogeng Zheng, Zikri Arslan, Hung-Chung Huang, Weidong Mao, Yi-Ming Liu
Cordyceps sinensis (C. sinensis) is a natural product that has diverse nutritional and medicinal values. Since the availability of natural C. sinensis becomes limited its authentication and quality control is of high significance. Herein we report on profiling of metals in C. sinensis by using inductively coupled plasma mass spectrometry (ICP-MS). The analysis reveals that C. sinensis contains a wide array of essential elements, including P, Mg, Zn, Cu, Fe, etc. Toxic metals detected are Cd, Pb, and As. In all five samples analyzed Pb contents are below 2...
January 28, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29104617/monitoring-carnosine-uptake-by-raw-264-7-macrophage-cells-using-microchip-electrophoresis-with-fluorescence-detection
#10
Claudia G Fresta, Michael L Hogard, Giuseppe Caruso, Elton E Melo Costa, Giuseppe Lazzarino, Susan M Lunte
Carnosine, a dipeptide found in a variety of tissues, is believed to possess antioxidant properties. It serves as a scavenger of reactive nitrogen and oxygen species (RNOS), which are important stress mediators of pro-inflammatory conditions and can lead to macrophage activation. In this study, intracellular concentrations of carnosine in murine RAW 264.7 macrophage cells were determined using microchip electrophoresis with laser-induced fluorescence detection following derivatization with naphthalene-2,3-dicarboxaldehyde and cyanide...
January 21, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28713441/analysis-of-raw-biofluids-by-mass-spectrometry-using-microfluidic-diffusion-based-separation
#11
Joshua Heinemann, Brigit Noon, Daniel Willems, Katherine Budeski, Brian Bothner
Elucidation and monitoring of biomarkers continues to expand because of their medical value and potential to reduce healthcare costs. For example, biomarkers are used extensively to track physiology associated with drug addiction, disease progression, aging, and industrial processes. While longitudinal analyses are of great value from a biological or healthcare perspective, the cost associated with replicate analyses is preventing the expansion of frequent routine testing. Frequent testing could deepen our understanding of disease emergence and aid adoption of personalized healthcare...
January 21, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28458724/online-fluorescence-anisotropy-immunoassay-for-monitoring-insulin-secretion-from-islets-of-langerhans
#12
Adrian M Schrell, Nikita Mukhitov, Lian Yi, Joel E Adablah, Joshua Menezes, Michael G Roper
Insulin secretion from islets of Langerhans is a dynamic process that is essential for maintaining glucose homeostasis. The ability to measure dynamic changes in insulin levels upon glucose stimulation from single islets will allow testing of therapeutics and investigating mechanisms of defective secretion observed in metabolic diseases. Most approaches to date for measurement of rapid changes in insulin levels rely on separations, making the assays difficult to translate to non-specialist laboratories. To enable rapid measurements of secretion dynamics from a single islet in a manner that will be more suitable for transfer to non-specialized laboratories, a microfluidic online fluorescence anisotropy immunoassay was developed...
January 7, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29201158/biomonitoring-method-for-the-analysis-of-chromium-and-cobalt-in-human-whole-blood-using-inductively-coupled-plasma-kinetic-energy-discrimination-mass-spectrometry-icp-ked-ms
#13
Joaudimir Castro Georgi, Yuliya L Sommer, Cynthia D Ward, Po-Yung Cheng, Robert L Jones, Kathleen L Caldwell
The Centers for Disease Control and Prevention developed a biomonitoring method to rapidly and accurately quantify chromium and cobalt in human whole blood by ICP-MS. Many metal-on-metal hip implants which contain significant amounts of chromium and cobalt are susceptible to metal degradation. This method is used to gather population data about chromium and cobalt exposure of the U.S. population that does not include people that have metal-on-metal hip implants so that reference value can be established for a baseline level in blood...
2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29181095/quantitation-of-fentanyl-analogs-in-dried-blood-spots-by-flow-through-desorption-coupled-to-online-solid-phase-extraction-tandem-mass-spectrometry
#14
Rebecca L Shaner, Nicholas D Schulze, Craig Seymour, Elizabeth I Hamelin, Jerry D Thomas, Rudolph C Johnson
An automated dried blood spot (DBS) elution coupled with solid phase extraction and tandem mass spectrometric analysis for multiple fentanyl analogs was developed and assessed. This method confirms human exposures to fentanyl, sufentanil, carfentanil, alfentanil, lofentanil, α-methyl fentanyl, and 3-methyl fentanyl in blood with minimal sample volume and reduced shipping and storage costs. Seven fentanyl analogs were detected and quantitated from DBS made from venous blood. The calibration curve in matrix was linear in the concentration range of 1...
2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29151901/surface-acoustic-wave-devices-for-chemical-sensing-and-microfluidics-a-review-and-perspective
#15
David B Go, Masood Z Atashbar, Zeinab Ramshani, Hsueh-Chia Chang
Surface acoustic waves (SAWs), are electro-mechanical waves that form on the surface of piezoelectric crystals. Because they are easy to construct and operate, SAW devices have proven to be versatile and powerful platforms for either direct chemical sensing or for upstream microfluidic processing and sample preparation. This review summarizes recent advances in the development of SAW devices for chemical sensing and analysis. The use of SAW techniques for chemical detection in both gaseous and liquid media is discussed, as well as recent fabrication advances that are pointing the way for the next generation of SAW sensors...
2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/29109756/imaging-acetaldehyde-formation-during-ethanol-metabolism-in-living-cells-using-a-hydrazinyl-naphthalimide-fluorescent-probe
#16
A G Reeves, M Subbarao, A R Lippert
The metabolism of ethanol to acetaldehyde has been visualized in living lung epithelial cells using a hydrazinyl naphthalimide fluorescent probe. Utilizing a condensation reaction between carbonyls and a hydrazine moeity, we demonstrate that the fluorescent probe (Aldehydefluor-1) AF1 reacts with a range of reactive carbonyl species including formaldehyde, acetaldehyde, glyoxylic acid, and methyl glyoxal. With AF1, it is possible to directly visualize endogenous carbonyl metabolites. Here, we have applied it towards the visualization of acetaldehyde generated from alcohol dehydrogenase mediated ethanol metabolism, validating it as a useful tool to study the roles of alcohol in respiratory disease and other pathological mechanisms...
2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28194233/checkpoints-for-preliminary-identification-of-small-molecules-found-enriched-in-autophagosomes-and-activated-mast-cell-secretions-analyzed-by-comparative-uplc-ms-e
#17
Chad P Satori, Marzieh Ramezani, Joseph S Koopmeiners, Audrey F Meyer, Jose A Rodriguez-Navarro, Michelle M Kuhns, Thane H Taylor, Christy L Haynes, Joseph J Dalluge, Edgar A Arriaga
We report the use of ultra high performance liquid chromatography (UPLC) coupled with acquisition of low- and high-collision energy mass spectra (MS(e)) to explore small molecule compositions that are unique to either enriched-autophagosomes or secretions of chemically activated murine mast cells. Starting with thousands of features, each defined by a chromatographic retention time, m/z values and ion intensities, manual examination of the extracted ion chromatograms (XIC) of chemometrically selected features was essential to eliminate false positives, occurring at rates of 33, 14 and 37% in samples of three biological systems...
2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28446924/differential-leukocyte-counting-via-fluorescent-detection-and-image-processing-on-a-centrifugal-microfluidic-platform
#18
Max L Balter, Alvin I Chen, C Amara Colinco, Alexander Gorshkov, Brian Bixon, Vincent Martin, Alexander Fromholtz, Timothy J Maguire, Martin L Yarmush
Centrifugal microfluidics has received much attention in the last decade for the automation of blood testing at the point-of-care, specifically for the detection of chemistries, proteins, and nucleic acids. However, the detection of common blood cells on-disc, particularly leukocytes, remains a challenge. In this paper, we present two analytical methods for enumerating leukocytes on a centrifugal platform using a custom-built fluorescent microscope, acridine orange nuclear staining, and image processing techniques...
December 21, 2016: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28496521/on-chip-fluorescent-labeling-using-reversed-phase-monoliths-and-microchip-electrophoretic-separations-of-selected-preterm-birth-biomarkers
#19
Mukul Sonker, Rui Yang, Vishal Sahore, Suresh Kumar, Adam T Woolley
On-chip preconcentration, purification, and fluorescent labeling are desirable sample preparation steps to achieve complete automation in integrated microfluidic systems. In this work, we developed electrokinetically operated microfluidic devices for solid-phase extraction and fluorescent labeling of preterm birth (PTB) biomarkers. Reversed-phase monoliths based on different acrylate monomers were photopolymerized in cyclic olefin copolymer microdevices and studied for the selective retention and elution of a fluorescent dye and PTB biomarkers...
November 21, 2016: Analytical Methods: Advancing Methods and Applications
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
#20
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
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