Natural Biosorbents for Detecting Emerging Contaminants in Tap and River Water via Pipette Tip Solid-Phase Extraction (PT-SPE)

Abstract

In this study, a pipette tip solid-phase extraction (PT-SPE) method was developed using cork powder as a natural biosorbent for the extraction of five pharmaceutical contaminants: diclofenac, ibuprofen, ketoprofen, bezafibrate, and fenoprofen. The method was applied to both spiked tap water and real river water samples. The cork powder was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis to assess its functional groups, morphology, and surface properties. The analytes were separated and quantified using reverse-phase high-performance liquid chromatography (RP-HPLC) with UV detection at 226 nm. Method optimization was performed by evaluating key parameters, including the amount of adsorbent, sample volume, and desorption solvent. The developed method demonstrated low limits of detection (LOD) ranging from 0.68 to 1.22 μg/L⁻¹ and limits of quantification (LOQ) between 2.06 and 3.68 μg/L⁻¹. The calibration curves exhibited good linearity (R² = 0.978–0.996) over the concentration range of 5–200 μg/L⁻¹. Satisfactory recoveries were obtained, ranging from 80.32% to 103.3%, with relative standard deviations (RSD) below 6.3%. In real river water samples, some analytes were detected even in non-spiked conditions, whereas no contamination was observed in non-spiked tap water.