Spectrophotometric determination of trace amounts of germanium in minerals and ores with 9-(o-chlorophenyl)-2,6,7-trihydroxyxanthen-3-one in the presence of cetyltrimethylammonium bromide
Abstract
A simple, highly sensitive and selective spectrophotometric method has been developed for the determination of germanium in a strongly acid medium (1.2 M H2SO4+ 3 M H3PO4) using 9-(o-chlorophenyl)-2,6,7-trihydroxyxanthen-3-one (o-chlorophenylfluorone, o-Cl-PF) in the presence of cetyltrimethylammonium bromide. The germanium complex exhibits an absorption maximum at 516 nm, and has a molar absorptivity of 1.82 × 105 l mol–1 cm–1. Beer's law is obeyed in the range 0–0.20 µg ml–1 of germanium, and the method is relatively free from interference from other metal ions. The method can be used to determine micro-amounts of germanium in minerals and ores without the isolation of germanium tetrachloride.