Journal of Radioanalytical and Nuclear Chemistry, Articles, Vol. 189, No. 1 (1995) 83.-87 EVALUATION OF THE TOLUENE-3,4-DITHIOL (TDT) - TRIOCTYLAMINE (TOA) SYNERGIC EXTRACTION SYSTEM M. MUFAZZAL SAEED, MUNIR AHMED, ,~KBAR ALl Nuclear Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, lslamabad (Pakistan) (Received September 5, 1994) Synergic extraaion of different essential and toxic metal ions such as Mn(II), Co(lI), Zn(ll), Hg(II), Cd(II) and Se(IV) has been carried out using toluene-3,4-dithiol (TDT) and trioctylanaine (TOA) in chloroform. A strong synevgic effect in the extraction of Co(II), Mn(ll) and Zn(II) has been observed. The effect of different anions on the extraction has also been analyzed. Ascorbate ions can easily separate Hg(II) and Se(IV) ions. The stability of synergic adduct and reaction mechanism are discussed. Toluene-3,4-dithiol (TDT) is a colorimetric reagent, which has been extensively used for the determination of molybdenum 1-3 and tungsten.4,5 Since the inlroduction of TDT as colorimelric reagent for molybdenum by HAMENCE 6 and MILLER,7,8 no work has been reported in the literature for its use as extracting reagent. Various neutral ligands such as triphenylphosphate (TPP), trioctylphosphine oxide (TOPO), tribenzylamine (TBA), di-n-butyl sulfoxide (DBSO), triphenylphosphine oxide (TPPO), diphenylamine (DPA) and trioctylamine (TOA) have been used with TDT for the extraction of metal ions at trace levels but none of them showed any synergic effect except trioctylamine (TOA). In order to understand this effect thoroughly, a systematic study has been carded out using TDT + TOA in chloroform as a synergic extraction system for Se(IV), Hg(II), Cd(II), Co(II), Mn(II) and Zn(II). Experimental Chemicals and radiotracers: All the chemicals and reagents used in this work were of AnalaR grade and were used as received. The radiotracers 6~ 56Mn, 65Zn, llSCd, 2~ and 75Se were prepared by irradiating the specpure metal or their oxides at a thermal flux of 2 9 1013 n 9 cm -2- s -1 in the PARR-1 research reactor of this institute. The irradiated metals or met,'d oxides were dissolved in conc. nitric acid, evaporated to near dryness and then diluted with deionized water. The radiochemical purity of the radiotracer was checked by a 25 cm 3 Ge(Li) detector coupled to a 4 K series 85 Canberra multichannel analyzer. Elsevier Science S. A., Lausanne Akad~miai Kiad6, Budapest