Magnetic solid-phase extraction based on Fe3O4 nanoparticle retrieval of chitosan for the determination of flavonoids in biological samples coupled with high performance liquid chromatography

A novel and facile magnetic solid-phase extraction method (MSPE) based on the two-step magnetic retrieval of chitosan was developed and applied for the first time in bio-matrix samples for the simultaneous extraction and determination of trace flavonoids. A systematic study of the different types of chitosan, Fe3O4 nanoparticles (NPs), the analytes and the matrices is presented. Owing to a higher extraction efficiency and capacity for analytes, chitosan with a 95% degree of deacetylation and average molecular weight of 1.0 x 10(6) and Fe3O4 NPs synthesized by the solvothermal method were selected as MSPE materials. Three analytes of luteolin, quercetin and kaempferol can be quantitatively extracted and simultaneously determined coupled with high performance liquid chromatography (HPLC) in urine and serum samples. No interferences were caused by proteins or endogenous compounds. Good linearities (r(2) > 0.9990) for all calibration curves were obtained, and the limits of detection (LODs) for quercetin, luteolin, and kaempferol were 1.0, 0.5 and 0.7 ng mL(-1) in urine samples and 10, 2 and 5 ng mL(-1) in serum samples, respectively. Satisfactory recoveries (90.1-106.5%, 91.1-105.5% and 93.5-108.8% for quercetin, luteolin and kaempferol) in biological samples were achieved.