Spectra of individual molecular isotopes in an unseparated natural mixture

A method is presented for extracting the spectra of individual isotopically labelled molecules from measurements on the unseparated natural mixture. Whenever such separate spectra were desired it was customary to obtain these from a different separation procedure or synthesis for each of the isotopic compounds of interest. Such individual spectra are useful in any systematic scheme of isotope separation with lasers. Our method is based on a rapid flow photoreactor synchronously illuminated with a tunable dye laser with gated detection of fragments in a mass spectrometer. As an application the technique produces the individual absorption spectra for ¹⁵N and ¹³C labelled sym-tetrazine by illuminating the natural isotopic mixture of unenriched sym-tetrazine.