A zirconium metal–organic framework functionalized with a S/N containing carboxylic acid (MOF-808(Zr)-Tz) as an efficient sorbent for the ultrafast and selective dispersive solid phase micro extraction of chromium, silver and rhodium in water samples

Metal-organic frameworks (MOFs) are good adsorbents for targeted chemicals with their adjustable properties. Herein, we prepared a zirconium based MOF (MOF-808(Zr)) and functionalized it employing 2-mercapto-4-methyl-5-thiazolacetic acid (MOF-808(Zr)-Tz). The prepared MOFs were characterized by XRD, FTIR, SEM-EDX, TGA, N2 sorption, zeta potential measurements and elemental analysis. The surface area of MOF-808(Zr)-Tz was 1348 m2/g. Dispersive solid-phase micro-extraction method based on MOF-808(Zr)-Tz was firstly developed and applied to the extraction of chromium, silver and rhodium in waters. The determination of the analytes were done by FAAS. The optimal pH and eluent for analytes were 7.0 and 3 mL of 2 mol L-1 HCl, respectively. The contact times were 1 min for adsorption and 3 min for elution. The LOD and PFs of the D-SPμE for analytes were 2.3 μg L−1 and 13.3 for chromium, 2.1 μg L−1 and 13.3 for silver, and 3.1 μg L−1 and 13.3 rhodium, respectively. The D-SPμE method was verified with analyses of NW-TMDA-54.6 and SPS-WW1 Batch 114 and with spiked dam water, river water, well water, sea water, and wastewater. The recoveries of the analytes changed from 89 to 108%. The results indicated that the method is selective, simple, effective and rapid for extracting chromium(III), silver(I) and rhodium(III) in waters.