Selective extraction and analysis of catecholamines in rat blood microdialysate by polymeric ionic liquid-diphenylboric acid-packed capillary column and fast separation in high-performance liquid chromatography-electrochemical detector

Concentration of blood catecholamines (CAs) is linked to a host of cardiovascular diseases, including hypertension and stenocardia. The matrix interferences and low concentration require tedious sample pretreatment methods before quantitative analysis by the gold standard method of high-performance liquid chromatography-electrochemical detector (HPLC-ECD). Solid phase extraction (SPE) has been widely used as the pretreatment technique. Here, a facile polymeric ionic liquid (PIL)-diphenylboric acid (DPBA)-packed capillary column was prepared to selectively extract dopamine (DA), noradrenaline (NE) and epinephrine (E) prior to their quantitative analysis by a fast separation in HPLC-ECD method, while microdialysis sampling method was applied to get the analysis sample. Parameters that influenced desorption efficiency, such as pH, salt concentration, acetonitrile content and wash time, were examined and optimized. The proposed method, combining microdialysis sampling technique, SPE and HPLC-ECD system, was successfully applied to detect CAs in rat blood microdialysate with high sensitivity and selectivity in small sample volumes (5-40 μl) and a short analysis time (8 min), yielding good reproducibility (RSD 6.5-7.7%) and spiked recovery (91-104.4%).