Preconcentration and separation of gold on modified silica gel

Selective preconcentration of gold in the form of ion associates of Au(III) chloro complex or Au(I) cyano complex with quaternary bases was studied us ing modified silica gel. Solutions containing gold in the presence of the c omplexing anion and a quaternary base were pumped through a Separon(TM) SGX C18 column. After elution with 96 vol.% ethanol, the eluate was evaporated in the presence a complexing agent (chloride or cyanide). The resulting aq ueous solutions were analyzed with inductively coupled plasma atomic emissi on spectrometry. The influence of concentration of onium salts, chlorides, nitrates, and the influence of the sample volume on the sorption were studi ed. The sorption flow rate and the elution volume were optimized, and the s eparation from a geological sample matrix was verified. The best recovery ( 100%) of preconcentration of Au(III) chloro complex was obtained with [1-(e thoxycarbonyl)pentadecyl] trimethylammonium bromide and 1-hexadecylpyridini um chloride at concentrations of 0.006 and 0.004 mol dm(-3), respectively. The sorption flow rate of a sample may vary in the range 0.4-7 cm(3) min(-1 ) the elution volume was between 5 and 6 cm(3) The recovery decreased with increasing sample volume above 250 cm(3) and was diminished by 10% in the p resence of nitrates above 0.4 mol dm(-3). Major accompanying elements Fe an d Mn, which considerably interfere at the Au I 242.795 nm line, were quanti tatively separated from gold. A Czech certified reference material 1001 Mok rsko was analyzed using the developed preconcentration technique and induct ively coupled plasma atomic emission spectrometry, inductively coupled plas ma mass spectrometry, and atomic absorption spectrometry. Sorption of ion a ssociates of Au(I) cyano complex was also efficient.