A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized
and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was
characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy
and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption
capacities for lead due to the chelation mechanism between metal cations and mercapto groups.
Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using
a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from
1 to 20 lg L1 was achieved with an enrichment factor of 100. The limits of detection and quantitation for
lead were found to be 0.29 and 0.97 lg L1, respectively. The developed method was successfully applied
to the determination of trace amounts of lead in food samples and certified reference material with satisfactory
results.