Simultaneous quantification of catecholamine and their metabolites in urine via mixed-mode magnetic bead-based...

An automated magnetic solid-phase extraction (MSPE) method was developed for the simultaneous enrichment and quantification of eight catecholamines and their metabolites in human urine. This method utilized carboxyl- and secondary amine-functionalized poly (polystyrene-co-divinylbenzene-co-N-vinylpyrrolidone) coated silica magnetic beads, combined with ID-LC-MS/MS. Through systematic optimization, the automated MSPE process efficiently extracted the target analytes from urine within 10 min. The validated method demonstrated excellent sensitivity and linearity over a range of 500-fold (with R² > 0.995 for all analytes), along with outstanding accuracy (recoveries of 95.22 % -104.07 %) and precision (RSD <10 %). No significant matrix effects or interference were observed. The method was successfully applied to analyze the samples from the 2024 National External Quality Assessment Program for Catecholamines and Their Metabolites (batches 202,411 and 202,412), where deviations for the eight analytes at two different concentrations ranged from -8.31 % to 10.43 %, confirming high accuracy and reliability. Furthermore, an inter-laboratory comparison showed a strong correlation between the results from our system and the established reference values, underscoring the method's consistency and reproducibility. Given its robustness and efficiency, this automated MSPE-ID-LC-MS/MS method serves as a valuable tool for diagnosing catecholamine-secreting tumors and contributes to the advancement of precision medicine and laboratory automation.