Selective Determination of Gold Ion in River Water by Solvent Extraction With 2-Thiazolidinethione, 4-(1-Methylethyl)-, (4s)-, Followed by Reversed Phase HPLC

Abstract

& A determination method for gold (Au) ion in river water has been developed by reversed phase HPLC. The Au(III) ion was quantitatively extracted into benzene from a weak alkaline solution as 2-thiazolidinethione, 4-(1-methylethyl)-, (4S)-(TTM) chelate. The extracted Au-TTM chelate was then separated on a C 18 column with an eluent of methanol=ethanol= 0.01 mol=L TTM (70:30:0.1, v=v) and detected at 270 nm. The correlation coefficients of the calibration curves obtained with 5 mL Au standards were more than 0.999 in the range of 1 lg=mL (ppm) to 10 ppm. The detection limit of the Au ion in 5 mL of water was estimated as 0.08 ppm, by a signal-to-noise ratio (S=N) ¼ 3. Relative standard deviations of peak areas (n ¼ 6) for 5 ppm Au standards was 1.0%. The recoveries with a spiked river water sample for 5 ppm Au ion (n ¼ 6) was 99.2 AE 0.6%. Effects of foreign ions on the determination of 2 ppm Au were investigated with 57 metal ions. Almost none of the ions interfered except for Ag(I), Cd(II), and Ti(IV) ions.