Dual-Wavelengths Spectrophotometric Determination of Trace Amounts of Copper with Dibromo-o-Nitrophenylflurone

Abstract

The reaction between copper (Cu²⁺) and the chromogenic reagent,
dibromo-o-nitrophenylflurone (DBNPF) was used for the determination
of trace amounts of copper by primary-secondary wavelength
spectrophotometry (PSWS). It was selective at pH 8 and selective in
the presence of fluoride and triethanolamine. The new dual-wavelength
spectrophotometry, PSWS, gave more precise and more accurate results
than ordinary spectrophotometry because it can utilize simultaneously
the peak absorption and the valley absorption of the reacted solution to
decrease the influence of excess of ligand. By analyzing several
samples, the relative standard deviations were less than 4.7% and the
recovery rate of Cu between 92.5 and 107%.