Ultrasensitive and multi-analyte detection of catecholamines in serum and cerebrospinal fluid using carboxyl-modified...

Catecholamines (CAs) are crucial markers of several disease. However, the existing method cannot afford enough target analytes and sufficient sensitivity. This study developed a new kind of carboxyl-functionalized hydrophilic lipophilic balanced magnetic beads (HLBMB-SCOOH) for efficient extraction and detection of CAs in human serum and cerebrospinal fluid (CSF). The microspheres were prepared via suspension polymerization and surface functionalization of carboxyl. As adsorbents in magnetic solid-phase extraction (MSPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS), they enabled ultrasensitive analysis of six catecholamines simultaneously. The established method exhibited excellent linear range of 10-10,000 ng/L, with a limit of detection as low as 1.33 ng/L. Satisfactory spiked recoveries of 88.2%-108.4% were achieved, with relative standard deviations below 9.1%. The samples of CSF and blood of subarachnoid hemorrhage (SAH) patients were analyzed by the proposed method, which showed consistently higher catecholamine concentrations in CSF than in blood across measured biomarkers. The proposed MSPE procedure is simple, efficient, and robust, providing a reliable approach for trace catecholamine analysis in blood serum and CSF, which may be used for treatment evaluation of SAH and other neurological disease.