Simultaneous and selective preconcentration of trace Cu and Ag by one-step displacement cloud point extraction for FAAS determination

Abstract

A simple, rapid and selective one-step displacement cloud point extraction (D-CPE) procedure was developed for the simultaneous preconcentration of trace Cu and Ag followed by flame atomic absorption spectrometric (FAAS) measurement. In this proposed procedure, Ni-DDTC complex instead of DDTC was used to achieve one-step extraction. Since the stability of Cu-DDTC and Ag-DDTC is higher than that of Ni-DDTC, simultaneous preconcentration of Cu and Ag can be achieved in a single step. Up to 15,000 mg L(-1) Co(2+), 10,000 mg L(-1) Zn(2+), 5000 mg L(-1) Cd(2+) and 5000 mg L(-1) Al(3+) did not cause significant interferences for the determination of 50 microg L(-1) Cu by FAAS, while 8000 mg L(-1) Zn(2+), 4000 mg L(-1) Co(2+), 4000 mg L(-1) Cd(2+) and 5000 mg L(-1) Al(3+) had no distinct effect on the determination of 80 microg L(-1) Ag. The limits of detection (LODs) of 0.5 microg L(-1) for Cu and 1.0 microg L(-1) for Ag, respectively, were obtained by FAAS detection. The accuracy of the proposed method is validated by analyzing certified reference materials (GBW 07405, GBW 07311 and GBW 07260) with satisfactory results. Furthermore, the one-step D-CPE was also applied for the preconcentration/separation of Cu and Ag in high-purity salts and artificial seawater, followed by FAAS or inductively coupled plasma-mass spectrometry (ICP-MS) determination.