RESONANT RAYLEIGH-SCATTERING FOR THE DETERMINATION OF TRACE AMOUNTS OF MERCURY (II) WITH THIOCYANATE AND BASIC TRIPHENYLMETHANE DYES

Intense resonance Rayleigh scattering (RRS) appears when mercury (II) reacts with thiocyanate and a basic triphenyhmethane dye (BTPMD), such as crystal violet (CV), ethyl violet (EV), brilliant green (BG), mala chite green (MG) or indine green (IG), to form an ion-association comp lex of the type (BTPMD)(2)[Hg(SCN)(4)]. The characteristics of RRS spe ctra of the ion-association complexes and suitable conditions for the reactions were investigated. The intensity of RRS is directly proporti onal to the concentration of mercury (II) in the range of 0 similar to 2.0 mu g/25 mi. The RRS methods have very high sensitivities for dete rmination of mercury (II); their detection limits are between 1.68 ng/ ml and 6.00 ng/ml on different dye systems. The effects of foreign ion s and ways to improve the selectivity were studied. The new highly sen sitive methods for the determination of trace amounts of mercury based on the RRS of the ion-association complexes have been developed.