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Spray Ionization (spray + ionization)

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Chemistry100%

Selected Abstracts

Desorption sonic spray ionization for (high) voltage-free ambient mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006
Renato Haddad
Sonic spray ionization is shown to create a supersonic cloud of charged droplets able to promote efficient desorption and ionization of drugs directly from the surfaces of commercial drug tablets at ambient conditions. Compared with desorption electrospray ionization (DESI), desorption sonic spray ionization (DeSSI) is advantageous since it uses neither heating nor high voltages at the spray capillary. DeSSI therefore provides a more friendly environment in which to perform ambient mass spectrometry (MS). DeSSI-MS is herein evaluated for the analysis of drug tablets, and found to be, in general, as sensitive as DESI-MS. The (high) voltage-free DeSSI method provides, however, cleaner mass spectra with less abundant solvent cluster ions and with enough abundant analyte signal for tandem mass spectrometry (MS/MS). These features may therefore facilitate the DeSSI-MS detection of low molar mass components or impurities, or both. The higher-velocity supersonic DeSSI spray also facilitates matrix penetration thus providing more homogenous sampling and longer lasting ion signals. Copyright © 2006 John Wiley & Sons, Ltd. [source]

A novel nanoflow interface for atmospheric pressure ionization mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2003
Atsumu HirabayashiArticle first published online: 23 JAN 200
A novel spray-ionization technique for nanoflow liquid chromatography/mass spectrometry (nLC/MS) has been developed by modifying the sonic spray ionization (SSI) technique. A solution from a tapered fused-silica capillary is sprayed by a gas flow coaxial to the capillary, and ions produced are analyzed with an ion-trap mass spectrometer. The ion intensity is shown to have a steep threshold at a low gas velocity and to be much less dependent on the gas velocity than that of conventional SSI, in which the ion intensity is strongly dependent on the gas velocity and reaches its maximum at sonic velocity. Thus, we conclude that the concentration of charge in the solution at the tapered capillary tip with an inner diameter of 15,,m is almost at saturation so that charged droplets are produced from the solution by electrical force, rather than by sheer stress due to the gas flow. The ions are readily produced from these charged droplets. Preliminary results are compared with results obtained with a miniaturized electrospray unit. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Does thermal degradation occur in laser spray ionization?

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2002
K. Hiraoka
A laser spray interface for use in liquid chromatography/mass spectrometry (LC/MS) has been investigated with respect to the degradation of the thermally labile compounds, ribostamycin, acetylcholine chloride, and cholesterol 3-sulfate sodium salt. It was confirmed that few fragment ions were formed when the laser beam was focused at the center of the stainless steel capillary, i.e., no wall heating. When the laser beam was slightly off-center, the sample ions suffered from thermal degradation by the heated wall of the stainless steel capillary to give fragment ions, which would be useful for the structural elucidation of the sample molecules. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Quantification of montelukast, a selective cysteinyl leukotriene receptor (CysLT1) antagonist in human plasma by liquid chromatography,mass spectrometry: validation and its application to a human pharmacokinetic study

BIOMEDICAL CHROMATOGRAPHY, Issue 8 2009
D. Vijaya Bharathi
Abstract A highly sensitive, rapid assay method has been developed and validated for the estimation of montelukast (MTK) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. Liquid,liquid extraction was used to extract MTK and amlodipine (internal standard, IS) from human plasma. Chromatographic separation was achieved with 10 mm ammonium acetate (pH 6.4): acetonitrile (15:85, v/v) at a flow rate of 0.50 mL/min on a Discovery HS C18 column with a total run time of 3.5 min. The MS/MS ion transitions monitored were 586.10 , 422.10 for MTK and 409.20 , 238.30 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.25 ng/mL and linearity was observed from 0.25 to 800 ng/mL. The intra-day and inter-day precisions were 5.97,8.33 and 7.09,10.13%, respectively. This novel method has been applied to a pharmacokinetic study of MTK in humans. Copyright © 2009 John Wiley & Sons, Ltd. [source]