2.4.1. Plasma, Urine and Semen

Peripheral blood was collected into 5 mL K3-EDTA vacutainer tubes and plasma was isolated by centrifugation at 4 °C. Urine was collected over 24 h into pre-weighed collection bottles containing K2-EDTA. Semen was collected into pre-weighed collection containers containing K2-EDTA and kept cold until processed. The plasma, urine and semen samples were extracted with perchloric acid containing DTPA, as described previously [12], prior to storage at −80 °C until HPLC analysis.
