2.6.1. Sample Preparation of Plasma Samples
In the first step, 10 μL of either sample plasma, QCs, water for blanks, or standards, together with 10 μL 3-NPH and 10 μL EDC-6, and 60 μL 75% MeOH were added to a tube and incubated at room temperature (RT) for 45 min with shaking (1600 rpm). Thereafter, the reaction was quenched by the addition of 10 μL quinic acid, followed by 15 min of incubation in RT with shaking, and centrifugation at 16,000× 