Spectrofluorometric analysis of amino acid mixtures: Implications for future space missions

► The optimum excitation wavelength for individual amino acid standard solutions is 390 nm. ► Except for isovaline the fluorescence maxima were found to be located consistently at 480 nm. ► Quenching ratio ranges from 1.4 in a 2-amino acid mixture to 2.2 in a 17-amino acid mixture. ► Isovaline cannot be detected below 10−5 M, while α-AIB is only detected above 10−6 M. ► Fluorescence spectroscopy provides fundamental specificity for the targeted molecules.