Fig. 1From: High-throughput analysis of amino acids in plant materials by single quadrupole mass spectrometryChromatogram of the standard amino acid solution showing an overlay of all mass channels. Differently coloured lines indicate different mass channels. All peaks had a corresponding stable isotope internal standard peak at the same retention time (not shown). The only exception was hydroxyproline for which no internal standard is available. Retention times of various amino acids are listed in Table 2Back to article page