نتایج جستجو برای: ionization techniques

تعداد نتایج: 664290  

2014
Bo Yan Gulen Yesilbag Tonga Singyuk Hou Patrick W. Fedick Yi-Cheun Yeh Felix S. Alfonso Tsukasa Mizuhara Richard W. Vachet Vincent M. Rotello

Synthetic host-guest chemistry is a versatile tool for biomedical applications. Characterization and detection of host-guest complexes in biological systems, however, is challenging due to the complexity of the biological milieu. Here, we describe and apply a mass spectrometric method to monitor the association and dissociation of nanoparticle (NP)-based host-guest interactions that integrates ...

Journal: :Drug discoveries & therapeutics 2007
T Santa O Y Al-Dirbashi T Fukushima

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESIMS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is frequently used to enhance the MS/MS detectability. The derivatization improves the separation and ionization efficiency. Moreover, the generated derivatives give par...

 In this paper, the laser ablation process based on the irradiation of nanosecond pulsed lasers on a copper target surface in the presence of Helium gas is studied. The dynamical behaviors of the generated plasma in the helium gas and evaporated copper at the atmospheric pressure are examined using a laser pulse, laser wavelength of and intensity of 7×1010W/cm2. A one-dimensional thermal model ...

Journal: :Medical physics 1988
W F Hanson D J Arnold R J Shalek L J Humphries

This is a word of caution to anyone using ionization chambers protected by thin rubber sheaths in water. Four Farmer-type ionization chambers contaminated with talcum powder were received for calibration by the Accredited Dosimetry Calibration Laboratory at the University of Texas M. D. Anderson Cancer Center. The chambers show a marked energy dependence (5% to 20%) to soft orthovoltage x rays....

Journal: :Journal of mass spectrometry : JMS 2000
Borth Hansel Rosner Junge

Numerous abused drugs of the 3,4-methylenedioxymetamphetamine (MDMA; Ecstasy; N-methyl-1-(3,4-methylenedioxyphenyl)-2-propaneamine) type and various alkyl chain- and aromatic ring-substituted isomers give very similar electron ionization (EI) mass spectra. This seriously affects the analysis of especially ring regioisomeric drug variants. Using collision-induced dissociation (CID) (argon) under...

پایان نامه :0 1375

this study examines the effetivenss of task-based activities in helping students learn english language structures for a better communication. initially, a michigan test was administered to the two groups of 52 students majoring in english at the allameh ghotb -e- ravandi university to ensure their homogeneity. the students scores on the grammar part of this test were also regarded as their pre...

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...

2016
Huanwen Chen Lijun Xie Huian Zhao Peng Zhou Tenggao Zhu Yongzi Liu

Ambient mass spectrometry has emerged as a significant tool to facilitate forensic investigation considering its well-known advantages of rapid, direct, nondestructive, high-throughput detection of a broad range of raw samples, as well as its potential capability of miniaturization and automation. New mass spectrometry technologies include more versatile ionization sources, allowing the next ge...

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