Density functional theory and mass spectrometry of phthalate fragmentations mechanisms: modeling hyperconjugated carbocation and radical cation complexes with neutral molecules.

This is the first ab initio study of the energetics of the fragmentation mechanisms of phthalate, by mass spectrometry, leading to protonated phthalic anhydride (m/z 149). Phthalates fragment by two major pathways; namely, the McLafferty + 1 rearrangement and the loss of alkoxy. Both pathways involve a carbonyl oxygen attack to the ortho-carbonyl carbon leading to structures with tetrahedral carbon intermediates that eventually give m/z 149.

Hydrogen rearrangement and ring cleavage reactions study of progesterone by triple quadrupole mass spectrometry and density functional theory.

The fragmentation mechanisms of progesterone have been studied by triple quadrupole tandem mass spectrometry (MSMS) and density functional theory (DFT). Mechanisms leading to major product ions are proposed. The data suggest that progesterone fragments preferentially via hydrogen and other rearrangements lead to neutral losses.

Positive chemical ionization triple-quadrupole mass spectrometry and ab initio computational studies of the multi-pathway fragmentation of phthalates.

We report the first positive chemical ionization (PCI) fragmentation mechanisms of phthalates using triple-quadrupole mass spectrometry and ab initio computational studies using density functional theories (DFT). Methane PCI spectra showed abundant [M + H](+), together with [M + C(2)H(5)](+) and [M + C(3)H(5)](+). Fragmentation of [M + H](+), [M + C(2)H(5)](+) and [M + C(3)H(5)](+) involved characteristic ions at m/z 149, 177 and 189, assigned as protonated phthalic anhydride and an adduct of phthalic anhydride with C(2)H(5)(+) and C(3)H(5)(+), respectively.

Removal and recovery of metals from a coal pile runoff.

The removal and recovery of heavy metals from a coal pile runoff water using a mixture of multiple metal-tolerant bacterial strains of ATCC 55673, and ATCC 55674 and a Pseudomonas sp. was investigated. The analysis of elemental composition of metal precipitates recovered from the bacterial biomass by transmission electron microscopy andenergy dispersive X-ray analysis revealed the presence of metals originally present in the wastewater.