Morphology-maintaining synthesis of copper hydroxy phosphate@metal - organic framework composite for extraction and determination of trace mercury in rice

A novel copper hydroxy phosphate@MOF composite DMP-Cu decorated by 2, 5-dimercapto-1, 3, 4-thiadiazol was facilely prepared and characterized. A dispersive SPE strategy using DMP-Cu as adsorbent combined with atomic fluorescence spectroscopy was developed for the selective capture of trace total mercury in rice sample. The adsorption mechanism showed that the Hg2+ removal process was fitted with pseudo second-order kinetics and the Langmuir adsorption model. The adsorbent was easy to be regenerated and the maximum adsorption capacity for the removal of Hg2+ was 249.5 mg g(-1) at the optimal pH of 4. X-ray photoelectron spectroscopy and Raman spectra verified the selective and strong interaction between Hg2+ and thiol/nitrogen-containing functional groups of DMTZ on DMP-Cu. The trace total mercury in rice samples was determined with detection limit of 0.0125 ng mL(-1) and relative standard deviation below 6%. The high recoveries were obtained in range of 98.8-109% for the spiked rice samples.

Automated summary

A novel DMP-Cu composite was prepared and characterized for the selective capture of trace total mercury in rice samples, showing good adsorption properties and recyclability. X-ray photoelectron spectroscopy and Raman spectra confirmed the selective and strong interaction between the composite and Hg2+.