Fig. 3. Lignin markers P18 and G18 in stems of maize of the transgenic Bt line (Novelis T, top) and the near-isogenic non-Bt line (Nobilis, bottom) obtained by thermochemolysis. Stationary phase: DB-5ms. The chromatograms (shown in mirror representation, time in min) present the sum of extracted ions acquired in full scan mode: molecular ion m/z = 192 amu for P18, molecular ion m/z = 222 amu for G18 and molecular ion m/z = 188 amu for phenanthrene-d₁₀ (internal standard, IST). Peak areas of the target analytes normalized to the peak areas of the internal standard for better comparison.