Application of solvent-assisted dispersive solid phase extraction combined with flame atomic absorption spectroscopy for the determination of trace amounts of Cadmium

Cadmium is recognized worldwide as a toxic metal. In this study, Solvent-Assisted Dispersive Solid Phase Extraction (SA-DSPE) combined with Flame Atomic Absorption Spectrometry (FAAS), was used for determination of trace amounts of Cadmium (Cd-II)) in drinking water samples.
In this approach, the dispersion of the sorbent was achieved by injecting a mixture of solution of the sorbent and dispersive solvent into the aqueous sample. Thereby, a cloudy solution formed. The cloudy solution was centrifuged and the enriched Cd (II) in the sediment phase dissolved in ethanol and determined by FAAS. Some effective parameters for SA-DSPE, such as: pH, concentration of chelating agent, type and amount of sorbent, type and volume of dispersive solvent and salt effect were investigated and optimized.
Under the optimized conditions, the detection limit for Cd (II) ions was 0.6 ng mL-1. Calibration curve was made in the range of 1-300 ng mL-1, obtaining good linearity (R2=0.9930). Finally, SA-DSPE was successfully applied for trace determination of Cd (II) in drinking water samples.
SA-DSPE is environment friendly and strongly against high contents of salt. The other benefits of the method are its simplicity, ease of operation, good precision, short extraction time, low cost, and a good enrichment factor.