Preparation of activated carbon and β-cyclodextrin modified magnetic nanoparticles for extraction and determination of hippuric acid in urine samples

In this study, a novel magnetic adsorbent (AC/β-CD/Fe 3 O 4 ) was prepared for the magnetic solid phase extraction (MSPE) of hippuric acid (HA) from urine. The adsorbent combined the high surface area of activated carbon (AC), the host-guest recognition of β-cyclodextrin (β-CD), and the magnetic responsiveness of Fe 3 O 4 . Under the optimal conditions, the method demonstrated excellent performance for HA detection, with a linearity range of 0.0064-1.0 µg/mL, low limit of detection of 1.9 µg/L, and high precision (RSDs < 5%). Recoveries from spiked urine matrices ranged from 95% to 99%, confirming the method's accuracy and practicality for monitoring HA in real biological matrices.