Preconcentration and determination of cadmiumin aqueous samples and human plasma by flame atomic absorption spectrometry after dispersive liquid-liquidmicroextraction

Author(s): Saeid Nazari,Azizollah Nezhadali,Mohadese Biabani, Hossein Eshghi

A novel approach for preconcentration and separation of trace amount of cadmium from aqueous samples was proposed by dispersive liquid–liquid microextraction (DLLME). Cadmium (II) was complexed with 2-[2- (2-aminophenyl) disulfanyl] benzamine (2APDSBA) as a complexing agent to form hydrophobic chelate and then extracted into the fine drops of extraction solvent which was dispersed into the aqueous sample by dispersive solvent. After extraction, the sedimented phase was analysed by flame atomic absorption spectrometry (FAAS). Some effective parameters on the DLLME such as type and volume of extraction and dispersive solvents, concentration of chelating agent, pH, centrifugation rate and time, extraction time and salt effect were investigated. Under the optimized conditions, the enrichment factor was 186.6. The calibration graph was linear in the range of 0.05-7.5 µg L-1 with correlation coefficient of 0.9985 under the optimum conditions of the recommended procedure. The detection limit based on the 3Sb criterion was 0.05 µg L-1 and relative standard deviation for (RSD) for ten replicate measurement of 0.2 µg L-1 and 2µg L-1 cadmium was 3.9 and 3.1 % respectively. In order to evaluate the accuracy and recovery of the presented method, the procedure was applied to the analysis of reference material, spiked water and human plasma.

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