Mesoporous CoO/SnO nanostructured composite as a selective and ultrafast adsorbent for simultaneous dispersive solid phase microextraction of cadmium, copper, and lead in spices, vegetables and water.

Dispersive solid phase microextraction (D-SPμE) has been widely used to separate and adsorb heavy metals in samples. However, most of the D-SPμE adsorbents have certain drawbacks, such as high extraction times, low selectivity, and low re-usability. In the current work, therefore, a mesoporous CoO/SnO nanostructured composite (CoO/SnO NC) was synthesized and characterized. It was employed as an adsorbent for simultaneous D-SPμE without vortexing of cadmium, copper, and lead in spices, water, and vegetables. The effect of analytical parameters on the D-SPμE was examined. pH, contact times, sample volume, and eluent were found to be 6.0, no need, 45 mL, and 2 mol L HCl (3 mL), respectively. The relative standard deviations (RSD%) and preconcentration factor (PF) were ≤ 2.0 % and 15. The adsorption capacity of the CoO/SnO NC was ≤85.7 mg g for analytes. The selectivity of the method was very high. Tolerable concentrations of Mg, Ca, K, and Na on copper and lead recoveries were rather high, being 50,000 mg L. These concentrations in mg L for cadmium were 50,000, 5000, 50,000 and 7500, respectively. The D-SPμE was verified by analysis of the certificate reference materials and added/recovery studies, showing recoveries in the range of 89 %-109 %. The cadmium, copper, and lead were successfully determined using the D-SPμE-FAAS method in well water, river water, seawater, wastewater, cinnamon, black pepper, parsley, carrot, potato, and squash. Therefore, CoO/SnO NC adsorbent can be a potential and suitable candidate for the D-SPμE of analytes in spice, water, and vegetable samples.