|SOFT - TIAFT 1998||Poster Session 4||Friday October 9, 1998|
SELECTIVE DETERMINATION OF TRACE AMOUNTS OF PSYCHOTROPIC PREPARATIONS BY SURFACE IONIZATION MASS-SPECTROMETRY: DERIVATIVES OF PHENOTHIAZINE|
Utkur Kh.Rasulev, Usman Khasanov, Erkin G. Nazarov, Dilshod T.Usmanov
Arifov Institute of Electronics of Uzbek Academy of Sciences, Tashkent, Uzbekistan
|At present the phenomenon of Surface Ionization (SI) of organic compounds belonging to classes of amines, hydrazines and their derivatives is well studied and the general rules of ion formation are formulated which permit forecasting the ion composition in the mass-spectra and the intensities of their fragment ions [Rasulev U.Kh., Zandberg E.Ya. "Progress in Surface Science", Vol. 28, No. 3/4, P.181-412, 1988].
This work demonstrates the possibilities of the SI mass-spectrometry in highly sensitive and selective analysis of psychotropic preparations from phenothiazine derivatives. Chlorpro-mazine manufactured in Russia was tested as a representative of the aliphatic group of phenothiazines, tioproperazine of pyperazine group, and periciazine (manufactured in France) was chosen as a representative of the pyperidine group.
The experiments have shown that the regularities of formation of the SI mass-spectra obey the general rules. However, the presence of two or more heteroatoms in a molecule leads to additional channels of molecule dissociation. In spite of this the mass-spectra are of few lines. Their composition and the temperature dependencies of ion currents demonstrate a high efficiency of formation of quasimolecular ions [M-H]+ and of fragments ions [M-Ri]+ (where M is a molecule, H is a hydrogen atom, Ri is a radical) which do not contain uncoupled electrons.
Under optimum experimental conditions the [M-H]+ ion intensities may reach up to 60% for chlorpromazine, 50% for tioproperazine and 10-15% for periciazine. The peculiarities of mass-spectra formation connected with the possible pathways of decay of molecules on the surface are discussed. The estimations show the amount of substance necessary for reliable identification was only 1 ng.