液珠萃取比色法测定化探样品中的金、银

Analysis of trace gold and silver in geochemical samples in extraction colorimetry

在10%HCl介质中,采取用二苯硫脲(DPTU)-甲基异丁酮(MIBK)泡沫塑料富集,以金试剂液珠萃取比色法,连续测定化探样品中Au和Ag.该方法机理在于当富集Au和Ag的DPTU-MIBK泡塑灰化后,用1+1HNO3溶解Ag,Au不溶于HNO3而留在残渣中.利用吸管吸取Ag的有色液珠,可将Au和Ag分离.方法的检出限(10g称样):Au0 5×10-9,Ag5×10-9.

Au and Ag contents in the samples are detected continuously using liquid beads extraction colorimetry after the samples are enriched by DPTU-MIBK foam in 10% HCl solution. When the foam enriching Au and Ag is incinerated, Ag can be dissolved in 1+1 HNO3 solution; while Au is still in the residue. Therefore, gold is separated from silver when the colored liquid bead containing silver is taken away by pipette. The method will fill in the gap in analytical technology by which Au and Ag can be continuously determined in small laboratory. The detection limits of Au and Ag are 05×0-9  and 5×10-9, respectively. This method can be used in field and is characterized by onthespot determination, easy operation and highspeed. It is shown by the standard samples and application test that the precision and accuracy can all accord with the demands of practice.