Cadmium(II)-based metal–organic nanotubes as solid-phase microextraction coating for ultratrace-level analysis of polychlorinated biphenyls in seawater samples

In this study, stable cadmium(II)-based metal–organic nanotubes (Cd-MONTs) were prepared and used as a coating material for solid-phase microextraction (SPME) of polychlorinated biphenyls (PCBs) from environmental water samples. The as-prepared Cd-MONT SPME coating material was characterized by thermal gravimetric analysis, scanning electron microscopy, and X-ray diffraction. The synthesized Cd-MONTs exhibited high thermal stability (385 °C) and excellent extraction performance toward PCBs. The important conditions were optimized systematically by the response surface method. Under the optimal conditions, the new fiber achieved high enrichment factors (938–3417), low limits of detection (1.80–8.73 pg L⁻¹), and wide linearity (10–5000 pg L⁻¹). The method developed was used in ultratrace-level analysis of PCBs in seawater samples, with satisfactory results for each sample.