Dissolved carbon dioxide flotation-assisted in-syringe dispersive liquid-liquid microextraction coupled with microsampling flame atomic absorption spectrometry for selective determination of palladium in water samples

Dissolved carbon dioxide flotation-assisted in-syringe dispersive liquid-liquid microextraction (DCF-IS-DLLME) followed by microsampling flame atomic absorption spectrometry was developed as a simple, inexpensive and fast method for extraction and determination of Pd(II). In the proposed approach, N,N'-bis (naphthylideneimino) diethylenetriamine (NAPdien) was utilized as a selective complexing reagent for Pd(II) ion. Several influential factors on the extraction efficiency including types and volumes of extraction and disperser solvents, pH of the sample solution, concentration of NAPdien and interfering ions were studied. By applying the optimal conditions, a preconcentration factor of 28.7 and limit of detection of 2.5 ng mL(-1) were provided by the proposed method. Linearity was in the range of 10-400 ng mL(-1) with a correlation coefficient (R (2)) of 0.9968. Intra-day RSD% values for five repetitive measurements of the spiked solutions at the concentrations of 20 and 100 ng mL(-1) were 5.2 and 2.4%, respectively, whereas it was obtained within the range of 3.6-18.6% for the real samples. Inter-day RSD% values of the spiked solutions were found to be 9.6 and 8.7%, respectively. The results demonstrated that except for Fe2+ and Fe3+, no remarkable interfering effect was created by the other studied ions for determination of Pd(II) so that the tolerance limits (W (Ion)/W (Pd(II))) of the major cations and anions were in the range of 1000-10,000. Finally, DCF-IS-DLLME was successfully applied for determination of Pd(II) in different water samples and the obtained relative recoveries in the range of 94.5-105% illustrated favorable accuracies for the proposed method.