Matrix-assisted laser desorption/ionization mass spectrometric study of bisquaternary ammonium antimicrobial agent decamethoxinum in 2,5-dihydroxybenzoic acid
T2N3
Matrix-assisted laser desorption/ionization mass
spectrometric study of bisquaternary ammonium
antimicrobial agent decamethoxinum in
2,5-dihydroxybenzoic acid
V.A. Pokrovskya, M.V. Kosevichb,V.L. Osaulenkoa, V.V. Chagovetsb,
V.A. Pashynskab,V.S. Shelkovskyb, V.A. Karachevtsevb,
A.Yu. Naumovc
aB.Verkin Institute for Low Temperature Physics and Engineering of the National Academy
of Sciences of Ukraine, 47 Prospekt Lenina, 61103 Kharkov, Ukraine.
E-mail: mvkosevich@ilt.kharkov.ua
bInstitute of Surface Chemistry of the National Academy of Sciences of Ukraine,
17 General Naumov Street, 03680 Kiev, Ukraine. E-mail: ucs@ln.ua
cBruker Ltd., 47 Leninsky Prospect, 119991 Moscow, Russia
Received 28 December 2004; revised: 23 June 2005
The results of investigation of decamethoxinum on matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer using 2,5-dihydroxybenzoic acid (DHB) matrix were presented. The MALDI mass spectra were obtained in the linear, reflectron and post source decay (PSD) modes. The spectra reveal diagnostic quasimolecular ions of the decamethoxinum [Cat·Cl]+ and [Cat – H]+. The PSD data confirm that the pathways of unimolecular decay of the [Cat·Cl]+ ions in the gas phase coincide with those of the salt thermal degradation via dequaternization; this agrees with the data obtained earlier with the use of secondary ion mass spectrometry. Abundant clusters containing Cat 2+ and anions those originate from the DHB matrix were observed, and it was suggested that they were stabilized either by the electrostatic interactions with the carboxylic group (carboxylate anion) of DHB or due to the cation-π interactions with the DHB aromatic ring.
