Bennett R.V.,Georgia Institute of Technology |
Gamage C.M.,Georgia Institute of Technology |
Gamage C.M.,Advion Inc. |
Galhena A.S.,Georgia Institute of Technology |
And 2 more authors.
Analytical Chemistry | Year: 2014
Mass spectrometry imaging (MSI) performed under ambient conditions is a convenient and information-rich method that allows for the comprehensive mapping of chemical species throughout biological tissues with typical spatial resolution in the 40-200 μm range. Ambient MSI methods such as desorption electrospray ionization (DESI) eliminate necessary sample preparation but suffer from lower spatial resolution than laser-based and vacuum techniques. In order to take advantage of the benefits of ambient imaging and to compensate for the somewhat limited spatial resolution, a secondary orthogonal separation nested in the imaging scheme was implemented for more selective discernment of tissue features in the spectral domain. Differential mobility spectrometry (DMS), an ion mobility-based separation that selectively transmits ions based on their high-to-low electric field mobility differences, can significantly reduce background chemical interferences, allowing for increased peak capacity. In this work, DESI DM-MSI experiments on biological tissue samples such as sea algae and mouse brain tissue sections were conducted using fixed DMS compensation voltages that selectively transferred one or a class of targeted compounds. By reducing chemical noise, the signal-to-noise ratio was improved 10-fold and the image contrast was doubled, effectively increasing image quality. © 2014 American Chemical Society. Source
Eikel D.,Advion Inc.
Rapid communications in mass spectrometry : RCM | Year: 2011
An automated surface-sampling technique called liquid extraction surface analysis (LESA), coupled with infusion nano-electrospray high-resolution mass spectrometry and tandem mass spectrometry (MS/MS), is described and applied to the qualitative determination of surface chemical residues resulting from the artificial spraying of selected fresh fruits and vegetables with representative pesticides. Each of the targeted pesticides was readily detected with both high-resolution and full-scan collision-induced dissociation (CID) mass spectra. In the case of simazine and sevin, a mass resolution of 100,000 was insufficient to distinguish the isobaric protonated molecules for these compounds. When the surface of a spinach leaf was analyzed by LESA, trace levels of diazinon were readily detected on the spinach purchased directly from a supermarket before they were sprayed with the five-pesticide mixture. A 30 s rinse under hot running tap water appeared to quantitatively remove all remaining residues of this pesticide. Diazinon was readily detected by LESA analysis on the skin of the artificially sprayed spinach. Finally, incurred pyrimethanil at a level of 169 ppb in a batch slurry of homogenized apples was analyzed by LESA and this pesticide was readily detected by both high-resolution mass spectrometry and full-scan CID mass spectrometry, thus showing that pesticides may also be detected in whole fruit homogenized samples. This report shows that representative pesticides on fruit and vegetable surfaces present at levels 20-fold below generally allowed EPA tolerance levels are readily detected and confirmed by the title technologies making LESA-MS as interesting screening method for food safety purposes. Copyright © 2011 John Wiley & Sons, Ltd. Source
Gao Z.,University of Oxford |
Lim Y.H.,University of Oxford |
Tredwell M.,University of Oxford |
Li L.,University of Oxford |
And 7 more authors.
Angewandte Chemie - International Edition | Year: 2012
The radiochemical synthesis of [18F]4-fluorophenols is based on phenol umpolung under oxidative conditions and direct nucleophilic fluorination with [18F]fluoride (see scheme, TBAF=tetra-n-butylammonium fluoride, TFA=trifluoroacetic acid). Readily available O-unprotected 4-tert-butyl phenols are used as precursors in this one-pot protocol. The reaction is completed in less than 30 minutes at room temperature and can be performed using standard or microfluidic technology. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Collier T.L.,Advion Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014
Microfluidics have revolutionized the field of radiopharmaceuticals in allowing for the rapid optimization of chemical processes and increased productivity in the preparation of radiotracers used in the development of imaging agents for clinical research and the study of biological processes. This presentation will cover the rapid preparation of radiotracers including simultaneous and sequential syntheses as well as the preparation of clinically useful amounts of radiotracers, as well as the rapid purification of such materials. © 2014 SPIE. Source
Scientific Analysis Instruments Ltd. and Advion Inc. | Date: 2012-08-01
Methods and systems for mass spectrometry and more particularly to an interface providing charged particles to a mass spectrometer are described herein.