Rapid spectrophotometric determination of ruthenium with diethazine hydrochloride

Diethazine hydrochloride reacts with ruthenium(III) instantaneously at high acidity (sulphuric or hydrochloric acid) to form a red 1:1 complex with absorbance maximum at 515 nm. A tenfold molar excess of reagent is necessary for complete complexation. Beer's law is obeyed for 1.0 to 10.4 ppm of ruthenium(III), with optimum concentration range 2 to 9 ppm. The molar absorptivity is 5.35 x 103 l.mol-1 cm-1. (author)