Metal-organic framework (MOF)are a great advanced adsorption material for solid-phase extraction due to the structure modifications with functional groups like sulfur that enhance the adsorption of heavy metals. A new sulfur-rich three-dimensional two-linker MOF (MIL-53(Fe)) was synthesized by grafting 2-mercapto-2-thiazoline sulfur and nitrogen as the second linker and then applied as an adsorbent in pipette tip micro solid-phase extraction (PT-μSPE) for the determination of Pb (II) and Cd (II) in environmental water samples. The MOFs were characterized by FTIR, XRD, TGA, BET, and SEM, which provide evidence for its framework, thermal stability, surface area, and morphology. Optimizations of extraction parameters such as pH, sample volume, volume of desorption solvent, and acidity of desorption solvent were made to improve the analytical perfor mance. Optimizations of extraction parameters such as pH, sample volume, volume of desorption solvent, and acidity of desorption solvent were made to improve the analytical performance. In the optimal conditions, higher surface area and adsorbent capacity per adsorbent weight were obtained for the newly synthesized adsorbent containing sulfur and nitrogen when compared to MIL-53(Fe). The linearity range of the developed method was 0.2–55 μg L 1 for Pb (II) and 0.04–20 μg L 1 for Cd (II), while it displayed exceptional linearity (r2 >0.99) and acceptable precision (RSD% ≤6.3). Thio-rich double-linker MIL-53 (Fe) as adsorbent in μSPE was applied for analysis spiked river, lake, groundwater, and wastewater samples with Pb (II) concentrations ranging from 5.0 to 20.0 μg L 1 and Cd (II) concentrations from 1.0 to 5.0 μg L 1, as well as standard reference materials. The results suggest that the double linker MIL-53(Fe) bearing thio-rich may offer greater adsorption capacity for Pb (II) and Cd (II) with a significantly lower detection limit compared to the original MIL-53(Fe).
