FLUOROMETRIC-DETERMINATION OF AL IN SEAWATER BY FLOW-INJECTION ANALYSIS WITH IN-LINE PRECONCENTRATION

A highly sensitive method for the shipboard determination of Al in seawater by now injection analysis (FIA) has been developed. The method employs in-line preconcentration of Al onto a column of resin-immobilized 8-hydroxyquinoline. The Al is subsequently eluted into the FIA system from the resin with acidified seawater. The eluted Al reacts with lumogallion to form a chelate, which is detected by its fluorescence. The fluorescence is enhanced similar to 5-fold by the addition of a micelle-forming detergent, Brij-35. The method has a detection limit of similar to 0.15 nM and a precision of 1.7% at 2.4 nM. The method has a cycle time of similar to 3 min and can be readily automated. The speed, ease of use, and relative freedom from contamination artifacts makes this method ideal for shipboard determination of Al in seawater.