LC-MS/MS determination of plasma catecholamines after selective extraction by borated zirconia.

For the first time, boronate affinity chromatography and metal oxide affinity chromatography mechanisms for cis-diol-compounds extraction are simultaneously realized on a single material, termed borated zirconia. This material was prepared by hydrolyzing zirconium butoxide with boric acid under non-aqueous environment. The diameter of formed particles is around 200 nm. By extracting catechol under different pH conditions or with phosphate ion competition, the dual affinity mechanisms of borated zirconia are confirmed. Benefiting from such unique feature, borated zirconia can function well under neutral condition. By using borated zirconia for dispersive solid phase extraction, specific capture of cis-diol-containing catecholamines, including epinephrine (E), norepinephrine (NE) and dopamine (DA), was achieved. A reliable LC-MS/MS method was established and validated for quantification of these target analytes in plasma samples after derivatisation with benzoyl chloride. The linear ranges are 0.010-0.200 ng·mL-1 for E and DA, and 0.050-1.000 ng·mL-1 for NE. The limits of quantification are 0.008, 0.020 and 0.004 ng·mL-1 for E, NE and DA respectively. By analyzing samples from healthy volunteers and schizophrenia patients, the plasma concentrations of E, NE and DA were found to be higher for the latter. Graphical AbstractSchematic representation of boronate combined metal oxide affinity chromatography (BMOAC) extraction of cis-diol catecholamines from human plasma by borated zirconia following with benzoyl chloride derivatization and LC-MS determination.