Liquid chromatography-mass spectrometry method for the determination of aldehydes derivatized by the Hantzsch reaction

A liquid chromatography-mass spectrometry method for the determination of a liphatic aldehydes after derivatization with acetylacetone or dimedone by m eans of the Hantzsch reaction is presented. Two molecules of a beta-diketon e, one molecule of ammonia and an aliphatic aldehyde cyclisate under format ion of colored and fluorescent reaction products. Atmospheric pressure chem ical ionization (APCI) and electrospray ionization (ESI) in the positive mo de are suitable to ionize the formed dihydropyridine and decahydroacridine derivatives under protonation of their basic secondary amine functionality. The method has been used to identify the oxidation product of the formalde hyde derivatives as side product. The acetaldehyde derivative, presumably f ormed in the reaction of residual acetaldehyde in the acetic acid or acetat e reagents, is mainly responsible for the increasing fluorescence backgroun d of the reagent solutions. (C) 1999 Elsevier Science BN. All rights reserv ed.