@article{oai:kanazawa-u.repo.nii.ac.jp:00010430,
 author = {Camagong, Cristina T. and Honjo, Takaharu},
 issue = {SUPPLEMENT},
 journal = {Analytical Sciences},
 month = {Jan},
 note = {A new solvent extraction technique for the separation of gold(III) at trace amounts from hydrochloric acid media was developed based on the formation of an ion-association complex of tetrachloro gold anion, AuCl4 - with 18-crown-6 (18C6) oxonium cation in 1,2-dichloroethane. The effect of various factors (crown ether, acid concentration, solvent, shaking time, stripping reagent etc.) on the extraction and separation of gold(III) was investigated. Quantitative extraction was achieved using 0.05 mol dm-3 18C6 in 1,2-dichloroethane at 4 mol dm-3 HCl within 5 min. Back-extraction was carried out by 5-min shaking with 0.1 mol dm-3 Na2S2O3 in 0.2 mol dm-3 NH3, followed by FAAS determination. Interference studies revealed excellent tolerance of the method to foreign ions. The method’s high selectivity was demonstrated by a spike recovery of >96% for gold(III) and by the negligible extraction of silver(I). Using first-class silver reagents, the quantitative recovery of traces of gold(III) was achieved up to a 20-fold preconcentration factor.},
 pages = {i725--i728},
 title = {Separation of Gold(III) as Its Ion-pair Complex with 18-Crown-6 from Hydrochloric Acid Media by Means of Solvent Extraction.},
 volume = {17},
 year = {2001}
}