Fast determination of catecholamines in human plasma using carboxyl-functionalized magnetic-carbon nanotube molecularly imprinted polymer followed by liquid chromatography-tandem quadrupole mass spectrometry

A novel, simple and sensitive method based on the use of dispersive micro-solid-phase extraction (d-μ-SPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the determination of catecholamines, i.e., dopamine (DA), norepinephrine(NE) and epinephrine (E), was developed and validated. The novel catecholamines molecularly imprinted polymer (MIP) on the surface of carboxyl-functionalized magnetic-carbon nanotube (CF@m-CNTs-MIP) was synthesized and characterized by vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The CF@m-CNTs-MIP was used as the d-μ-SPE sorbent to extract catecholamines from human plasma samples. The obtained results demonstrated the higher extraction capacity of CF@m-CNTs-MIP with recoveries between 87.5-110%. The limits of quantification (LOQs) for NE, E and DA were 76 ng/L, 18 ng/L and 10 ng/L, respectively. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of catecholamines in 120 healthy volunteers demonstrated the applicability to clinical studies.