Determination of catecholamines in rat plasma by oasis HLB solid-phase extraction and high-performance liquid chromatography with electrochemical detection

A quantitive assay for the determination of catecholamines in rat plasma was established by Oasis HLB solid-phase extraction(SPE)and high-performance liquid chromatography(HPLC) with electrochemical detection.An accurate solid-phase extraction was utilized to pretreat cetacholamine complexation with diphenylborate.With Atlantis C_(18) column as the solid phase,the influence of various parameters on chromatographic performance,such as the composition and pH of the mobile phase,and the detection potential,was investigated.The average extraction recoveries for all catecholamines including E,NE,and DA were in the range of 90%～95%.It had good linear relationship between concentration and peak area while the concentration of NE,E,and DA ranged from 0.25 ng/mL to 30 ng/mL(r is 0.9989,0.9992,and 0.9984 respectively).Relative standard deviation for intra-day precision and for inter-day precision was less than 4% and 8%,respectively,for all three analytes.The detection limit is 0.4 pg.The method has high precision and accuracy,good selectivity,high sensitivity and feasibility.