Bruce Mattson

Metal speciation by means of microbore columns with direct-injection nebulization by inductively coupled plasma atomic emission spectroscopy

Abstract Ion chromatography can be used to perform speciation of several elements. This paper examines the use of ion chromatography with inductively coupled plasma atomic emission spectroscopy detection. A new type of nebulizer, the direct-injection nebulizer, was used to introduce the sample into the plasma. Columns were developed to interface with the direct-injection nebulizer at a flow-rate of 80–100 μl/min. The speciation of arsenic, selenium and chromium is discussed.

Structural characterization of dissolved organic matter: a review of current techniques for isolation and analysis

Natural dissolved organic matter (DOM) in aquatic systems plays many environmental roles: providing building blocks and energy for aquatic biota, acting as a sunscreen in surface water, and interacting with anthropogenic compounds to affect their ultimate fate in the environment. Such interactions are a function of DOM composition, which is difficult to ascertain due to its heterogeneity and the co-occurring matrix effects in most aquatic samples. This review focuses on current approaches to the chemical structural characterization of DOM, ranging from those applicable to bulk samples and in situ analyses (UV-visible spectrophotometry and fluorescence spectroscopy) through the concentration/isolation of DOM followed by the application of one or more analytical techniques, to the detailed separation and analysis of individual compounds or compound classes. Also provided is a brief overview of the main techniques used to characterize isolated DOM: mass spectrometry (MS), nuclear magnetic resonance mass spectrometry (NMR) and Fourier transform infrared spectroscopy (FTIR).

Ion-molecular reactions of free phenylium ions, generated by tritium β-decay with group V–VII elements

Abstract Generation of free phenylium ions, obtained by tritium β-decay and their ion-molecular reactions with Group V–VII elements are described. The elaborated nuclear–chemical method has been used for the synthesis of tritium-labeled organic derivatives containing these Group V–VII elements.

Kinetics and thermodynamics of the intramolecular isomerization of [Fe(SCH3(CO)3]4

Abstract The kinetics and thermodynamics of the isomerization of syn- and anti-[Fe(SCH3)(CO3)]2 were investigated over the temperature range 40–70°C in chloroform and other solvents. In chloroform the thermodynamic parameters for the isomerization syn → anti are ΔH = 1.4 ± 1.1 kcal/mol, ΔS = 6.0 ± 2.6 cal/mol°K, ΔG298 = −0.4 ± 1.9 kcal/mol. The kinetic parameters for the same reaction are ΔH‡ = 28.4 ± 1.4 kcal/mol , ΔS‡ = 27.9 ± 4.2 cal/mol°K , and ΔG‡ 298 = 21.1 ± 2.6 kcal/mol . The isomerization is first order in both direction and probably involves FeS bond rupture and reformation. The equilibrium constant, Kχ = [anti]/[syn] varies from 1.89 ± 0.22 at 40°C to 2.26 ± 0.18 at 70°C. The rate of isomerization increases with solvent polarity hexane

Ion-molecular reactions of free phenylium ions, generated by tritium β-decay with bidentate arenes

Abstract Generation of free phenylium ions, obtained by tritium β-decay and their ion-molecular reactions with bidentate arenes are described. The elaborated nuclear-chemical method has been used for the synthesis of tritium labeled organic derivatives using halobenzenes. Two alternative pathways for interaction of the phenylium ion with the bidentate arene, addition to the lone pair of the halogen or substitution on the aromatic ring, were revealed.