Schematic procedure for compound confirmation, illustrated with examples of both confirmed (right half) and excluded (left half) compounds. (a) TIC of the Titan aerosol analog (blue line) and standard samples (black line). (b)–(c) Mass components at corresponding retention times for hydroxyproline and hypoxanthine. (d)–(e) Comparison of the relative intensities of four ion pairs between the sample and the standards.