Preparation and preliminary evaluation of anhydrous tris(2,2'- bipyridyl)ruthenium(III) perchlorate as a temporally stable reagent for analytical chemiluminescence

A new method for producing solutions of tris(2,2'- bipyridyl)ruthenium(III) ([Ru(bipy)3]3+) which have significantly improved stability over other methods is presented and preliminary analytical evaluation of the reagent for chemiluminescence is reported. The synthesis of anhydrous tris(2,2'-bipyridyl)ruthenium(III) perchlorate ([Ru(bipy)3](ClO4)3) salt is described and the use of acetonitrile as solvent to minimise the presence of water which can be oxidised by [Ru(bipy)3]3+, which causes the inherent instability. The stability of the new reagent in acetonitrile was monitored spectrophotometrically (λ(max)~674 nm) and a decrease of <6% was observed. A flow injection analysis experiment was conducted using codeine to generate chemiluminescence to quantify the stability of the new reagent over 50 h. The results show a decrease in the chemiluminescence signal of <8%, which is a considerable improvement over previous methods.