Development of lithium attachment mass spectrometry - knudsen effusion and chemical ionisation mass spectrometry (KEMS, CIMS).

Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting, sensitive and robust method for the detection of volatile species in the gas phase. The design, manufacture and results of lithium based ion attachment ionisation sources for two different mass spectrometry systems are presented. In this study trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure measurements are made using a modified Knudsen Effusion Mass Spectrometer (KEMS).

[Tinea capitis in the University Hospital of Constantine (Algeria)].

Although benign, tinea capitis are a public health problem and a frequent complaint in children. In Algeria, these disorders have long been known; their high frequency was related to unfavorable social conditions of people both in cities than in rural areas. Our aim is the study of tinea capitis diagnosed in the laboratory of Parasitology and Mycology of the University Hospital of Constantine through a retrospective review of 15 consecutive years from 1997 to 2011.

Dissociation energetics of the phenol(+)⋯Ar(2) cluster ion: The role of π→H isomerization.

The dissociation energetics in the phenol(+)⋯Ar(2)(2π) cluster ion have been investigated using photoionization efficiency and mass analyzed threshold ionization spectroscopy. The appearance energies for the loss of one and two Ar atoms are determined as ∼210 and ∼1115 cm(-1), respectively. The difference between the appearance energy for the first Ar ligand in phenol(+)⋯Ar(2)(2π) and the dissociation energy of the phenol(+)⋯Ar(π) dimer (535cm(-1)) is explained by the isomerization of one π-bound Ar ligand to the OH binding site (H-bond) upon ionization.

A novel experimental system of high stability and lifetime for the laser-desorption of biomolecules.

A novel laser desorption system, with improved signal stability and extraordinary long lifetime, is presented for the study of jet-cooled biomolecules in the gas phase using vibrationally resolved photoionization spectroscopy. As a test substance tryptophane is used to characterize this desorption source. A usable lifetime of above 1 month (for a laser desorption repetition rate of 20 Hz) has been observed by optimizing the pellets (graphite/tryptophane, 3 mm diameter and 6 mm length) from which the substance is laser-desorbed.

A tandem ion trap/ion mobility spectrometer.

A tandem quadrupole ion trap/ion mobility spectrometer (QIT/IMS) has been constructed for structural analysis based on the gas-phase mobilities of mass-selected ions. The instrument combines the ion accumulation, manipulation, and mass-selection capabilities of a modified ion trap mass spectrometer with gas-phase electrophoretic separation in a custom-built ion mobility drift cell. The quadrupole ion trap may be operated as a conventional mass spectrometer, with ion detection using an off-axis dynode/multiplier arrangement, or as an ion source for the IMS drift cell.