Multi-element determination in some foods and beverages using silica gel modified with 1-phenylthiosemicarbazide

1-Phenylthiosemicarbazide bonded modified silica gel (PTC-SG) was synthesised and characterised by FTIR, SEM and elemental analysis for a novel separation/preconcentration of multiple elements based on solid phase extraction. The analytical parameters including pH of solutions, amounts of PTC-SG, flow rates of sample, eluent type and sample volume were optimised. The adsorption capacities of PTC-SG were found to be 7.9, 6.4, 6.3, 8.3, 7.2, 8.9 and 6.6 mg/g for Cu(II), Cd(II), Pb(II), Co(II), Cr(III), Ni(II) and Mn(II), respectively. The limit of detection (LOD) was calculated as 3x the standard deviation(s) of the reagent blank (k = 3, N = 21) and the LOD values were obtained to be 0.98 µg L⁻¹ (Cu), 0.65 µg L⁻¹ (Cd), 0.57 µg L⁻¹ (Pb), 1.12 µg L⁻¹ (Co), 1.82 µL⁻¹ (Cr), 1.67 µg L⁻¹ (Ni) and 0.55 µg L⁻¹ (Mn). Certified reference materials were used to test the validation of the present method. The new solid phase extraction method was successfully applied to determination of the amount of multiple elements in food and beverage samples.