Human whole blood samples from healthy adults (male volunteers) were collected in tubes containing heparin as an an-ticoagulant (volume ratio: 9:1) on the day of the experiment (blood came from the Regional Blood Transfusion Centre, Kraków, Poland). The volunteer donors had not taken any medicines for the two weeks prior to the withdrawal. Informed consent was given by each volunteer prior to the blood withdrawal and the study was in accordance with the principles outlined in the World Medical Association (WMA) Declaration of Helsinki, as well as Bioethical Commission of the Jagiellonian University. 300 µL of whole blood were kept for the measurements. Remaining whole blood was subjected to centrifugation (acceleration of 800 g and run time: 15 min at room temperature, with soft stop) to separate plasma from the rest of the blood components. Plasma was collected and placed in Eppendorf tubes for further sample preparation procedures and measurements. 0.2 ml of whole blood and plasma were transferred to NMR tubes and flame-sealed without degassing. The samples were kept at 4 • C to reduce the metabolism until measurement and measured up to an hour after blood withdrawal.