Figure 3.

HPLC chromatograms of (a) Linagliptin (10 µg mL⁻¹) and the proposed degradation product (2 µg mL⁻¹). (b) Multiple reaction monitoring (MRM) chromatogram (a) of linagliptin (m/z = 473.11–420.07) and the degradation product (m/z = 285.05–156.93) and HPLC chromatogram (b) of a lab prepared mixture of linagliptin (80 µg mL⁻¹) and the degradation product (50 µg mL⁻¹).