Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry

The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in the presence of 0.1% Triton X-114 and 2 × 10⁻⁴ mol L⁻¹ 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL⁻¹ silver. The calibration graph was linear in the range of 10–200 ng mL⁻¹, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples.