Astraphloxin Cyanine Dye as a Reagent for the Selective Extraction-Photometric Determination of Trace Mercury(II)

A procedure was developed for the extraction-photometric determination of low concentrations of mercury(II) in aqueous solutions. It is based on the reaction of the Hg Br ₃ ^? acidocomplex with the Astraphloxin cationic dye to give an ion pair extracted with toluene. The detection limit for mercury is 0.015 mg/L. Effects of a number of heavy metal cations on determining mercury(II) were studied. It was shown that these effects appear in the presence of 500-fold molar amounts of interferents. The procedure was used for determining mercury(II) in the presence of 200-fold molar amounts of some heavy metal cations. The relative standard deviation was no worse than 5%.