Fluorimetric determination of trace amounts of gold as an ion-association complex with 2-phenylbenzo[8,9]quinolizino[4,5,6,7-fed]phenanthridinylium perchlorate

Abstract

The synthesis, characterisation and applications of 2-phenylbenzo[8,9]-quinolizino[4,5,6,7-fed]phenanthridinylium perchlorate (PQPP) as a reagent for the formation of ion-association complexes is described. This reagent reacts with AuCl₄^– to produce a 1:1 complex in 0.5 M hydrochloric acid, which is slightly soluble in water and can be extracted into isoamyl acetate with an extraction efficiency of 90.7%. The PQPP shows an intense fluorescence and is used for the fluorimetric determination of trace amounts of gold in the range 0.2–1.75 µg per 5 ml of organic layer. The interferences of many metallic ions have been examined and under appropriate working conditions the method is applicable to the determination of gold in lead.