نتایج جستجو برای: electrospray ionization esi

تعداد نتایج: 47193  

Journal: :Journal of clinical microbiology 2014
Kerryl E Greenwood-Quaintance James R Uhl Arlen D Hanssen Rangarajan Sampath Jayawant N Mandrekar Robin Patel

We compared PCR-electrospray ionization mass spectrometry (PCR-ESI/MS) to culture using sonicate fluid from 431 subjects with explanted knee (n = 270) or hip (n = 161) prostheses. Of these, 152 and 279 subjects had prosthetic joint infection (PJI) and aseptic failure, respectively. The sensitivities for detecting PJI were 77.6% for PCR-ESI/MS and 69.7% for culture (P = 0.0105). The specificitie...

Journal: :Molecules 2017
Runsheng Xu Rongrong Cai Sixian Zhou Zhuoda Zhou Beibei Li Dihui Xu

The reaction mechanism of Cu-catalyzed C-H hydroxylation/C-S coupling was studied using electrospray ionization high resolution mass spectrometry (ESI-HR MS) and density functional theory calculations (DFT). Notably, a series of CuI and CuIII complexes were observed as key intermediates and identified using ESI-HR MS. Furthermore, a catalyst cycle involving proton abstraction/oxidative addition...

Journal: :Analytical chemistry 2008
Anders Nordström Elizabeth Want Trent Northen Janne Lehtiö Gary Siuzdak

A multiple ionization mass spectrometry strategy is presented based on the analysis of human serum extracts. Chromatographic separation was interfaced inline with the atmospheric pressure ionization techniques electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in both positive (+) and negative (-) ionization modes. Furthermore, surface-based matrix-assisted laser ...

Journal: :Analytical chemistry 2013
Yury Kostyukevich Alexey Kononikhin Igor Popov Oleg Kharybin Irina Perminova Andrey Konstantinov Eugene Nikolaev

A method to enumerate labile hydrogens in all constituents of molecular ensemble of natural organic matter (NOM) based on our previously developed simple hydrogen/deuterium (H/D) exchange (electrospray ionization (ESI) ion source (Kostyukevich et al. Anal. Chem. 2013, 85, 5330) and ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry is presented. The method was app...

Journal: :The journal of physical chemistry letters 2012
Mitra Almasian Josipa Grzetic Johanne van Maurik Jeffrey D Steill Giel Berden Steen Ingemann Wybren Jan Buma Jos Oomens

The conjugate base of para-coumaric acid, which can be conveniently generated in the gas phase by electrospray ionization (ESI), is a commonly used model system for the chromophore of the photoactive yellow protein. Here we report its gas-phase IR spectrum, which shows that the anion easily adopts a carboxylate structure lying 60 kJ/mol higher in energy than the global minimum phenoxide structu...

2012
Zsuzsanna Kovács Zoltán Dinya Sándor Antus

spectrometry using electrospray (ESI) and sonic spray (SSI) ionization for the characterization of nonvolatile phenolic compounds is tested using the special Hungarian wine Tokaj aszu of 1983 vintage. Besides caffeic-, ferrulic-, chlorogenic-, and 3,4-dimethoxycinnamic acids; 3,4-dimethoxycinnamoyl-, ferruloyl-, and galloyl-glucose; gentisic acid-b-∆-glucoside; theogallin; and resveratrol-3-O-b...

Journal: :Analytical chemistry 2002
Tomoyoshi Soga Yuki Ueno Hisako Naraoka Keiko Matsuda Masaru Tomita Takaaki Nishioka

We describe a method, based on pressure-assisted capillary electrophoresis coupled to electrospray ionization mass spectrometry (PACE/ESI-MS), that allows the simultaneous and quantitative analysis of multivalent anions, such as citrate isomers, nucleotides, nicotinamide-adenine dinucleotides, and flavin adenine dinucleotide, and coenzyme A (CoA) compounds. Key to the analysis was using a nonch...

2016
Rulin Wang Lin Zhang Zunjian Zhang Yuan Tian

Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) techniques for liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of levonorgestrel were evaluated. In consideration of difference in ionization mechanism, the two ionization sources were compared in terms of LC conditions, MS parameters and performance of method. The sensitivity for detection...

The lack of authentic standards has limited the quantitative analysis of herbal drugs in biological samples. The present work demonstrated a practicable strategy for the assay of herbs and their metabolites independent of authentic standards. A liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI–MS) method for the qualitative and quantitative determination of the metabolites...

2001
Robert J. Hondal Bradley L. Nilsson Ronald T. Raines

Instruments. NMR spectra were obtained with Bruker AC-300 and Varian UNITY-500 spectrometers. Mass spectra were obtained with Perkin Elmer Sciex API 365 electrospray ionization (ESI) and Bruker Biflex III matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) instruments at the University of Wisconsin Biotechnology Center. Ultraviolet and visible absorbance was recorded with a C...

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