Representative MRM chromatograms of a blank DBS sample (A), DBS spiked with MTXPGs (final total concentration of 100 nM) subjected to enzymatic conversion to MTXPG1 (B), and DBS sample spiked with MTXPG1–5 measured individually at a final concentration of 100 nM each (C).

<p>Representative MRM chromatograms of a blank DBS sample (A), DBS spiked with MTXPGs (final total concentration of 100 nM) subjected to enzymatic conversion to MTXPG1 (B), and DBS sample spiked with MTXPG1–5 measured individually at a final concentration of 100 nM each (C).