A sensitive and simple flotation-spectrophotometric method for the determination of microgram amounts of silver using Schiff base 2-[(2-mercaptophenyliminio)methyl]phenol

摘要

A simple and sensitive spectrophotometric procedure for the determination of microgram amounts of silver has been developed. The method is based on the flotation of the complex of Schiff base, 2-[(2-mercaptophenylimino)methyl]phenol (MPMP), and silver at the aqueous solution-chloroform interface. The complex was then separated and dissolved in 5 mL of methanol, and its absorbance was measured at 330 nm. The quantitative flotation of the complex was possible from 5-140 mL of the aqueous phase in the pH range of 1-5. For a 100-mL aliquot of the water sample, the Beer's law was obeyed over the range from 1 x 10(7) to 5 x 10(-6) M of silver. The Sandell's sensitivity was 6.9 x 10(-9) mol cm(-2) for a 0.001 absorbance unit. The method is simple, rapid, free from the interference of many cations and anions, and has a wide linear range. The procedure was successfully applied to the determination of trace amounts of silver in tap water, well water, waste water in the mining industries, and a lead-concentrate reference material. The accuracy was assessed using either a recovery experiment and independent analysis with standard additions, or the analysis of certified reference materials.