Application of ion-exchanger phase visible light absorption to flow analysis. Determination of vanadium in natural water and rock

Ion-exchanger phase visible light absorptiometry combined with flow analysis has been developed and applied for the determination of vanadium in natural water and rock. The vanadium(IV) and vanadium(V) in the sample solution reacted with xylenol orange (XO) which was immobilized on the AG 1-X2 anion-exchanger packed in flow-through cell, and the increase in light absorption caused by the formation of the vanadium-XO complex in the resin was directly measured with a spectrophotometer at 532 nm. The interference by most of the co-existing ions can be effectively eliminated using trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid (CyDTA) and ammonium tartrate. The detection limit was 80 ng dm−3 with 5.0 cm3 of sample solution. Vanadium contents in three sample solutions could be determined within 1 hour.