Ionic imprinted polymer based solid phase extraction for cadmium and lead pre-concentration/determination in seafood

The experimental parameters for SPE extraction in column mode, such as pH of the digested sample, sample volume, load rate, and elution rate, have been optimized. The optimum pH for quantitative Cd and Pb retention was 8.5, and the elution was completed with 2 mL of 2.0 M nitric acid. Cadmium and lead concentrations in the acid extracts were determined by ETAAS using palladium and magnesium nitrates as a chemical modifier. The limits of detection (LODs) and limits of quantification (LOQs) obtained were 0.15 and 0.52 μg L− 1 for Cd determination, and 0.50 and 1.68 μg L− 1 respectively for Pb determination. Taking into account the mass of sample used and the preconcentration factor (12.5), the LODs obtained were 0.21 and 0.67 ng g− 1 for Cd and Pb respectively. These limits are adequate to determine Cd and Pb at levels lower than the maximum levels allowed in fresh marine products, by the European Union legislation. The optimized method was applied for Cd and Pb determination in different seafood samples, such as squid, hake, sardine, horse mackerel, grouper and gilthead bream, and it was possible to detect both metals in all samples.