Gas chromatography/ Mass spectroscopy determination of organic acids via their anilides and their halogenated derivative forms

The characteristic mass spectra of both anilide and of the aliphatic acids exhibited several common peaks, such peaks served as a criterion for their presence beside that most fragmentation pattern selected and followed nearly the same route that it is provide unequivocal structural confirmation of the identity and can also be used for highly sensitive quantification by selected ion monitoring. The electron impact and chemical ionization mass spectra were used as ionization source since these sources have the advantage of creating both positively and negatively charged sample ions, and are well -suited to analysis of polar molecules. The quadrupole ion trap as mass analyzers has the advantage of mass accuracy measurements and achievable high resolution. Derivative procedures were applied to the aliphatic acids including acetic, propionic, isobutyric, and butyric acids. Dynamic headspace sampling technique was performed successfully to created gas phase of the standards of monoacids at lower concentrations. comparison of the polyteflon flouro-ethvlene (PTFE) of pore size 0.2μm with the polycarbonate film (5μm) immediately displays a great difference in permeability, being about two orders of magnitudes greater through the polycarbonate membrane than PTFE. (author)