Spectrophotometric Determination of Gold (III) after Liquid-Liquid Extraction and Selective Pre-concentration with a Novel Dibenzo-18-Crown-6 Derivative


BULUT V. N. , DURAN C., BIYIKLIOĞLU Z., Tufekci M., SOYLAK M.

GEOSTANDARDS AND GEOANALYTICAL RESEARCH, cilt.35, ss.471-483, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 35 Konu: 4
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1111/j.1751-908x.2011.00093.x
  • Dergi Adı: GEOSTANDARDS AND GEOANALYTICAL RESEARCH
  • Sayfa Sayıları: ss.471-483

Özet

A selective and sensitive method for the extraction and spectrophotometric determination of gold with N,N'-6,7,9,10,17,18,20,21-octahydrodibenzo[b,k][1,4,7,10,13,16] hexaoxacyclo-octadecine-2,13diylbis(2-chloroacetamide) (ODBOCA) is described. The ODBOCAAu(III) complex was extracted from a slightly acidic aqueous solution (pH 5) into a chloroform layer and then the absorbance of the extract was measured using a UVVis spectrophotometer with 1.0 cm quartz cells at 540 nm. An enrichment factor of 200 was achieved. In the chloroform medium at 540 nm, the molar absorptivity and Sandells sensitivity were 4.12 x 103 l mol-1 cm-1 and 0.048 mu g cm-2, respectively. Beers law was obeyed in the range of 0.515 mu g ml-1 in the measured solution. The relative standard deviation for ten replicate samples at the 1.0 mu g ml-1 level was 3.0%. The limit of detection, based on 3s, was 0.5 mu g l-1 in the original sample. The effects of pH, ligand concentration and shaking time were studied. The ratio of the metal ion to ligand molecules in the complex was found to be 1:2 according to the Job Method. The effects of interference by a number of metal ions were investigated. The method was verified with certified reference materials and spiked tests, and quantitative recovery values were obtained. The method was fast, accurate, selective and precise, and was applied to the determination of gold in water and ore with good results.