Journal of The American Society for Mass Spectrometry, 2004
The carbon-bonded gas-phase Meisenheimer complex of 2,4,6-trinitrotoluene (TNT) and the nitrometh... more The carbon-bonded gas-phase Meisenheimer complex of 2,4,6-trinitrotoluene (TNT) and the nitromethyl carbanion CH2NO 2 − (m/z 60) is generated for the first time by chemical ionization using nitromethane as the reagent gas. Collision-induced dissociation (CID) of the Meisenheimer complex furnishes deprotonated TNT, a result of the higher gas-phase acidity of TNT than nitromethane. The formation of Meisenheimer complexes with CH2NO 2 − in the gas phase is selective to highly electron-deficient compounds such as dinitrobenzene and trinitrobenzene and does not occur with organic molecules with lower electron-affinity such as methanol, methylamine, propionaldehyde, acetone, ethyl acetate, chloroform, toluene, m-methoxytoluene, and even nitrobenzene and p-fluoronitrobenzene. As such, the reaction allows selective detection of TNT in mixtures. Meisenheimer complexes between CH2NO 2 − and the three dinitrobenzene isomers display distinctive fragmentations. The oxygen-bonded σ-complex of TNT with the deprotonated hemiacetal anion CH3OCH 2 − (m/z 61), represents a different type of Meisenheimer complex. It displays characteristic fragmentation involving loss of HNO2 upon CID. The combination of a selective ion/molecule reaction (Meisenheimer complex formation) followed by a characteristic CID process provides a second novel and highly selective approach to the detection of TNT and closely related compounds in mixtures. The assay is readily implemented using neutral loss scans in a triple quadrupole mass spectrometer. Gas-phase reactions of denitrosylated TNT with benzaldehyde produce the corresponding dihydrofuran in an aldol condensation, a result that parallels the corresponding condensed-phase reaction.
This paper examines jobs in the information society and the new economy, taking as its focus the ... more This paper examines jobs in the information society and the new economy, taking as its focus the call center industry. More specifically, the study analyzes the degree of variability of the quality of call center jobs. In order to achieve this objective, an index of job quality is generated, and an empirical analysis of the characteristics of jobs in call centers is carried out. This allows us to determine the level and variability of quality of jobs in this sector and to establish whether the reality of these jobs is as good as the forecasts for work in the new economy.
Journal of The American Society for Mass Spectrometry, 2004
The carbon-bonded gas-phase Meisenheimer complex of 2,4,6-trinitrotoluene (TNT) and the nitrometh... more The carbon-bonded gas-phase Meisenheimer complex of 2,4,6-trinitrotoluene (TNT) and the nitromethyl carbanion CH2NO 2 − (m/z 60) is generated for the first time by chemical ionization using nitromethane as the reagent gas. Collision-induced dissociation (CID) of the Meisenheimer complex furnishes deprotonated TNT, a result of the higher gas-phase acidity of TNT than nitromethane. The formation of Meisenheimer complexes with CH2NO 2 − in the gas phase is selective to highly electron-deficient compounds such as dinitrobenzene and trinitrobenzene and does not occur with organic molecules with lower electron-affinity such as methanol, methylamine, propionaldehyde, acetone, ethyl acetate, chloroform, toluene, m-methoxytoluene, and even nitrobenzene and p-fluoronitrobenzene. As such, the reaction allows selective detection of TNT in mixtures. Meisenheimer complexes between CH2NO 2 − and the three dinitrobenzene isomers display distinctive fragmentations. The oxygen-bonded σ-complex of TNT with the deprotonated hemiacetal anion CH3OCH 2 − (m/z 61), represents a different type of Meisenheimer complex. It displays characteristic fragmentation involving loss of HNO2 upon CID. The combination of a selective ion/molecule reaction (Meisenheimer complex formation) followed by a characteristic CID process provides a second novel and highly selective approach to the detection of TNT and closely related compounds in mixtures. The assay is readily implemented using neutral loss scans in a triple quadrupole mass spectrometer. Gas-phase reactions of denitrosylated TNT with benzaldehyde produce the corresponding dihydrofuran in an aldol condensation, a result that parallels the corresponding condensed-phase reaction.
This paper examines jobs in the information society and the new economy, taking as its focus the ... more This paper examines jobs in the information society and the new economy, taking as its focus the call center industry. More specifically, the study analyzes the degree of variability of the quality of call center jobs. In order to achieve this objective, an index of job quality is generated, and an empirical analysis of the characteristics of jobs in call centers is carried out. This allows us to determine the level and variability of quality of jobs in this sector and to establish whether the reality of these jobs is as good as the forecasts for work in the new economy.
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Papers by AL Eisenheim