Selection of electrophoric derivatives of 1-aminopyrene and 2-aminofluorene for determination by gas chromatography with electron-capture negative-ion mass spectrometry.

Several electrophoric derivatives of 1-aminopyrene and 2-aminofluorene were prepared. Reagents such as heptafluorobutyryl chloride, pentafluorobenzoyl chloride, pentafluorobenzyl bromide and pentafluorobenzaldehyde, alone and in certain combinations, were employed. The ease of formation, yield, stability and fragmentation by gas chromatography with electron-capture negative-ion (ECNI) mass spectrometry of the derivatives were compared. This allowed the most promising ones to be selected for future work on the sensitive detection of aminopolyaromatics by this detection technique. Pentafluorobenzylidene (first choice) and N-pentafluorobenzyl-N-heptafluorobutyryl (second choice) derivatives emerged as the best ones. The origins of losses of HF and 2HF from some of the derivatives were elucidated in the ECNI mass spectra by studies of deuterium-labeled analogues.