Laser photofragment spectroscopy: a new technique for the detection of N-nitrosamines and other nitroso compounds.

The potential of laser photofragment spectroscopy (LPS) for the detection and discrimination of nitrosamines, alkyl nitrites, thionitrites and C-nitroso compounds has been evaluated. The technique combines high sensitivity with the dramatic specificity of high-resolution spectroscopy and utilizes pulsed laser photodissociation with synchronized detection of the NO photofragment by laser-induced fluorescence (LIF). Using supersonic molecular beam sampling and wavelength tunable photodissociation, LPS can generate well-resolved finger-print spectra characteristic of the parent nitroso compound.

A method for the investigation of free and protein-bound N-nitrosoproline in beer.

Hydrolysis of beer peptides and proteins by both mild enzymatic and vigorous alkaline conditions has established that peptide-bound N-nitrosoproline residues are not present in beer in significant quantities. Free N-nitrosoproline remains the single most abundant identified N-nitroso compound, and this accounts for up to 10% of the apparent total N-nitroso compounds (ATNC). Both hydrolysis and extractability studies strongly indicate that the majority of the ATNC are not associated with beer peptides, but rather are likely to be low molecular weight possessing in some cases an acidic functional group.