Publications by authors named "Bryan E Tomlin"

3 Publications

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Solvent-Free Synthesis of Nano Zirconium Phenylphosphonates with Molten Phenylphosphonic Acid.

Chemistry 2020 May 28;26(28):6185-6194. Epub 2020 Apr 28.

Department of Chemistry, Texas A&M University, College Station, Texas, 77843-3255, USA.

Nanosized α-zirconium phenylphosphonate particles were successfully prepared by the reaction between different zirconium sources and molten phenylphosphonic acid in the absence of solvent. The resultant nanoplates exhibit particle sizes in the range of 15 to 30 nm. The use of a topotactic anion exchange method starting from α-zirconium phosphate instead resulted in the generation of 15 to 180 nm plates, while also resulting in nanoparticles with a higher degree of crystallinity. The topotactic anion exchange of the phosphate groups by phenylphosphonate groups could be performed to completion when performed in molten phenylphosphonic acid. Characterization of both the final products as well as the individual steps in the anion exchange were performed by powder XRD, fast neutron activation analysis, TGA, FTIR spectroscopy, TEM, solid-state NMR and XPS.
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http://dx.doi.org/10.1002/chem.201905110DOI Listing
May 2020

Molecular Colocalization Using Massive Gold Cluster Secondary Ion Mass Spectrometry.

Anal Chem 2018 11 18;90(21):12692-12697. Epub 2018 Oct 18.

Department of Chemistry , Texas A and M University , College Station , Texas 77843 , United States.

We report on the ion emission from impacts of hypervelocity massive gold clusters for use in secondary ion mass spectrometry. Two massive gold clusters are considered, 520 keV Au and 1040 keV Au. The emission of fragment ions and molecular ions is evaluated for a series of neat samples, glycine, phenylalanine, arginine, and gramicidin S. A 2 to 4-fold increase of molecular ion emission is observed from impacts of 1040 keV Au versus 520 keV Au. Compared to impacts of 20 keV Ar and 20 keV (HO) in static conditions, impacts of 1040 keV Au display a 6 to 9-fold increase in the number of detected molecular ions per projectile impact. To explain the increased emission of molecular species, we examine the size of the impact craters and calculate the ratio of molecular ions to fragment ions. The characterization of Au and the operating conditions of the gold liquid metal ion source are presented.
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http://dx.doi.org/10.1021/acs.analchem.8b02950DOI Listing
November 2018

Improvements in determinations using the Cu-64 annihilation gamma rays.

Appl Radiat Isot 2009 Dec 20;67(12):2075-8. Epub 2009 May 20.

National Institute of Standards and Technology, Analytical Chemistry Division, 100 Bureau Drive MS 8395, Gaithersburg, MD 20899-8395, USA.

The method of gammagamma coincidence counting has been applied to the determination of Cu via the (64)Cu annihilation gamma rays. Preliminary experiments show that at least an order of magnitude reduction in (24)Na interference may be obtained by employing the 511-511 keV coincidence peak rather than the singles 511-keV peak. The effect of the sample matrix on the yield of (24)Na pair-production events was investigated by a combination of experimental measurements and Monte Carlo calculations.
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http://dx.doi.org/10.1016/j.apradiso.2009.05.002DOI Listing
December 2009