INTRODUCTION Because of poor toxicity, low cost, enhanced separation selec- tivity, non-flammability, capability of simultaneously separating hydrophilic and hydrophobic solutes and non-volatility, micellar mobile phases (i.e. solutions containing a surfactant at a concentra- tion above its critical micellar concentration (CMC) have found in- teresting applications in liquid chromatography [1-8]. The use of micellar mobile phases (MMP) in thin-layer chromatography (TLC) was first proposed by Armstrong and co-workers [9-10]. MMP have been successfully utilized to separate pesticides and biphenyls [10], polynuclear aromatic hydrocarbons and vitamins [11], phenols [12], amino acids [13-14], alkaloids [15], dyes [16] and drugs [17]. Despite evident advantageous features, the use of MMP in chromatographic analysis of metal cations [18-20] has been less extensive compared with their use in the analysis of or- ganic compounds. In addition to simplifying chromatographic procedure, MMP result in improved separations as a result of electrostatic, hydro- phobic and donor-acceptor interactions, or any combination of these [9, 11, 12, 16]. Secondary interactions arising from partition- ing of solute within the mobile phase (between aqueous and micel- lar phases) also play a decisive role in the separation of solutes by micellar liquid chromatography. According to literature [2, 3, 20, 21], chromatographic performance of MMP can be further im- proved by using them in the presence of salts and organic additives which affect the size of micelles. Several analytical techniques [22 -26] have been used to separate Au (III), Cu (II) or Ag (I) from as- sociated metal ions but the work on simultaneous separation of these metal cations from their three component mixtures by TLC is lacking. This communication reports a simplest and convenient mi- cellar TLC procedure for the separation of co-existing Au (III), Cu (II) and Ag (I) ions. The mutual separation of Au (III), Ag (I) and Original Thin-Layer Chromatography of Certain Metal Cations with Anionic Micellar Mobile Phase Systems: Simultaneous Separation of Co-existing Gold (III), Copper (II) and Silver (I) and Quantitative Spectrophotometric Measurement of Copper (II) Ali Mohammad*, Yasir Hamid Sirwal and Sufia Hena Analytical Research Laboratory, Department of Applied Chemistry, Faculty of Engineering & Technology, Aligarh Muslim University, Aligarh-202 002, INDIA Received September 5, 2003 Revised manuscript received October 25, 2003 Accepted November 9, 2003 *E-mail: mohammadali 4 u@rediffmail.com Fax no.: +91-571-2702758 SUMMARY Silica gel in combination with surfactant-mediated eluents has been used for thin-layer chromatography of sixteen metal cations. Several combinations of mobile phase systems comprising of sodium dodecyl sulfate (SDS) plus organic non-electrolytes and inorganic electrolytes have been tested for rapid and reliable separation of metal cations. TLC system constituting silica gel as a stationary phase and 0.3% SDS (pH 2.3) plus 5% aqueous NaCl (9:1, v/v) as mobile phase was identified most favorable system for the separation and identification of co-exist- ing gold, copper and silver in alloys. Semiquanititative determination of Cu 2+ , Co 2+ , Ni 2+ and Cd 2+ by spot-area measurement method has been attempted. TLC-spectrophotometry technique has been used for quantitative determination of Cu 2+ in synthetically prepared ores and alloys with preliminary separation from Au 3+ and Ag + . Key words: Micellar TLC, Separation, Metal cations, Gold, Copper, Silver, Spectrophotometry Chromatography, Vol.24 No.3 (2003) Original ―１３５―