Table 1. HPLC and autosampler parameters.

HPLC parameters
Autosampler loop volume	10 μL
Autosampler needle volume	2.6 μL
Autosampler tray temperature	4-8 °C
Trap column	5 × 0.3 mm, PepMap 100 C18, 5 μm particle, 100 Å (Dionex, ThermoFisher Scientific)
Analytical column	100 × 0.075 mm, ReproSil-Pur C18-AQ, 3 μm particle (Dr. Maisch GmbH)
Column temperature	45 °C
Gradient	Time	Mobile phase B (%)	Flow rate
(Loading)	0	2	10
	1.5	2	10
(Elution)	1.5	2	0.3
	3	2	0.3
	18	40	0.3
	19	90	0.3
	20	90	0.3
	21	2	0.3
	30	2	0.3