Development and feasibility of emulsion breaking method for the extraction of cadmium from omega-3 dietary supplements and determination by flow injection TS-FF-AAS

• EIEB is a very simple method for the extraction of Cd2 + from the fish oil.
• Similar results were achieved by EIEB and microwave-assisted acid digestion procedure.
• The EIEB associated with TS-FF-AAS is rapid and sensitive for Cd2 + determination in fish oil.
• The limit of detection of method was found to be 2.5 ng g− 1.

In the present study a new method for the determination of Cd2 + in omega-3 dietary supplement employing extraction induced by emulsion breaking (EIEB) and thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was described. The method was based on the formation of a water-in-oil emulsion by the addition of extractor solution constituted by 3.54% (m/v) Triton X-114 and 1.16 mol L− 1 HNO3 in the oil sample and further breaking of this emulsion by heating. Two well-defined phases were formed and the acid aqueous one containing the extracted cadmium ions was analyzed by TS-FF-AAS using a flow injection system. Different parameters that exert influence on the extraction efficiency of Cd2 + were optimized by means of chemometric tools. The limits of detection and quantification were found to be 2.5 and 8.3 ng g− 1, respectively using a calibration curve made in aqueous medium. The accuracy of the proposed method was assured by good agreement with the results achieved by microwave-assisted acid digestion procedure without statistical differences (confidence interval of 95%) and by spiking the samples with known concentrations of 50 ng g− 1 Cd2 +. The content of Cd2 + in the samples was varied from 37.3 up to 54.5 ng g− 1.