SELECTION OF CONDITIONS FOR CHROMATO-MASS SPECTROMETRIC DETERMINATION OF A NEW 2-AMINO PYRROLO DERIVATIVEWITH CYTOTOXIC ACTIVITY

Abstract

The aim of study is to select optimal conditions for tandem mass-spectrometric detection of a new biologically active compound with cytotoxic activity.Material and methods. The object of the study was the substance 2-ABPPK (2-amino-1-(4-bromophenyl)-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-4,5-dihydro-1 H -pyrrole-3-carboxamide). The studies were carried out on an LCMS-8050 liquid chromatography-mass spectrometer (Shimadzu) with a triple quadrupole type detector. Chromatographic separation was carried out on a column with a reversed-phase sorbent using an eluent based on acetonitrile and 0.1% formic acid solution.Results and conclusions. In the course of the studies, it was found that the use of electrospray ionization leads to the formation of molecular ions similar to the protonated or deprotonated 2-ABPPK molecule. The mass spectrum obtained in the positive ionization mode contains ions with m/z 392 and 394; with negative ionization, ions with masses of 390 and 392. The doublet of signals in the mass spectra is explained by the presence of a bromine atom in the structure of the compound.Based on the study of the fragmentation of molecular ions in the cell of collisional dissociation, ion pairs were selected for the implementation of the MRM mode (monitoring of multiple reactions) in the detection of 2-ABPPK: 394→377; 392→375;392→349;390→347. It was shown that the use of these MRM transitions provides a high sensitivity for the determination of 2-ABPPK, which is necessary for pharmacokinetic studies. Detection limit of 2-ABPPK upon injection of 1 μl of the sample was no more than 240 femto-grams in the positive ionization mode and not more than 750 femtograms in the negative ionization mode.