A spectrophotofluorometric study of compounds of biological interest.

Since the observation of Desha (1) that the fluorescence exhibited by solutions of quinine and aniline erythrosine when irradiated by ultraviolet light could be utilized for their quantitative determination, useful fluorimetric methods have been devised for a number of biological constituents (2). The extreme sensitivity of fluorimetric assay offers a distinct advantage over other chemical and physical methods, but instrumental limitations have restricted its application to a relatively small number of compounds. Among the most serious of these limitations have been the unavailability of activating light of high intensity over a wide range of wavelengths, and the restriction of fluorescence detection to the visible region of the spectrum. The adequate fluorimetric methods that are available, notably those for riboflavine (4), thiamine (3), and adrenaline (5,6) are possible because each fluorophor absorbs light corresponding to the wavelength of one of the few available lines of the mercury emission spectrum,2 and emits visible fluorescence. In addition, the fluorescence of thiamine and adrenaline must be induced by chemical change, a requisite common to many fluorimetric procedures. Recent papers from this laboratory (7-10) describe the design and