Determination of <scp>Se</scp> ( <scp>IV</scp> ) in Urine Samples Using Au/ <scp>PDDA</scp> Composite Nanoparticles Modified Glassy Carbon Electrodes Coupled With Packed‐Fiber Solid‐Phase Extraction

ABSTRACT Coupled with packed‐fiber solid‐phase extraction (PFSPE), a novel electrochemical method was fabricated for determination of Se (IV) based on Au/PDDA composite nanoparticles (Au/PDDA NPs) and glassy carbon electrode (GCE). Gold nanoparticles (Au NPs) were synthesized by reduction method and then modified by poly(diallyldimethylammonium) (PDDA). Using a drop coating technique, the obtained Au/PDDA NPs were added to the surface of the electrode for electrochemical detection. Before electrochemical analysis, urine samples were pretreated by PFSPE column with poly(styrene‐co‐0.5% poly(diallyldimethylammonium)) (PS‐0.5% PDDA) nanofibers as the adsorbent. Au NPs were characterized by Transmission Electron Microscope (TEM), UV–Visible spectrometry, Dynamic light scattering (DLS), and Zeta potential. PS‐0.5% PDDA nanofibers were characterized by Fourier transform infrared spectroscopy (FT‐IR), Scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET). Analytical conditions were optimized in this work, and the electrochemical sensor modified by Au/PDDA NPs (Au/PDDA@ES) exhibited excellent reproducibility, repeatability, and stability. The linear range for detection of Se (IV) was from 5 to 1000 ng mL −1 with the detection limit of 2 ng mL −1 (S/ N = 3). Furthermore, Au/PDDA@ES was successfully employed to detect Se (IV) in human urine.