Progress in microfluorometric identification of monoamine fluorophores

Techniques for the microfluorometric identification of monoamine fluorophores have been put forward along two different lines: (1) extension of the excitation range into the far UV and (2) computer-assisted on-line scanning recordings in combination with an automatic microfluorometric identification of fluorophores. By an extension of the excitation range to 250 nm it is possible to distinguish fluorophores of DOPA from those of dopamine, fluorophores of noradrenaline from those of adrenaline, and fluorophores of 5-OH-tryptophan from those of 5-OH-tryptamine. In a computer-assisted on-line scanning procedure using a high-aperture inverted illuminating microscope equipped with UV transmitting optics the specific formaldehyde-induced catecholamine fluorescence is characterized microfluorometrically by corrected ratios of excitation maxima (370:320 nm and 320:275 nm). Excitation data are plotted out with corresponding coordinates in the x- and in the y-axis. Furthermore the digitized values of fluorescence intensities obtained with the scanning procedure are processed according to principles of automatic image-analysis procedures.