Magnetic nanoparticles grafted with β-cyclodextrin for solid-phase extraction of 5-hydroxy-3-indole acetic acid

We describe the synthesis of -cyclodextrin modified magnetic nanoparticles (CD-mNPs) as a material for solid-phase extraction of the cancer biomarker 5-hydroxy-indole-3-acetic acid (5-HIAA) from urine. The CD-mNPs were characterized by TEM, FTIR, and XRD, and the kinetics and adsorption isotherms were studied. The strong interaction between the CD-mNPs and 5-HIAA is the main driving force for recognition and extraction, while the magnetic core of the NPs allows their separation from the sample matrix. Recovery of 5-HIAA from the adsorbent using an adequate solvent regenerated the adsorbent for further use. 5-HIAA was then quantified by fluorometry of its complex with -CD. The method works in the 1 Au 10(-7) to 1 Au 10(-5) mol L-1 (R-2 0.9982-0.9996) concentration range, and the limits of detection (3 sigma) and quantification (10 sigma) of the method are 1.2 Au 10(-8) mol L-1 and 4.01 Au 10(-8) mol L-1 5-HIAA, respectively. The recovery of 5-HIAA from urine samples spiked with 5-HIAA in three concentrations (1.4 Au 10(-6), 4.50 Au 10(-6) and 1.0 Au 10(-5) mol L-1) are within 63 +/- 3 %.