FLOW-INJECTION SPECTROFLUOROMETRIC METHOD FOR THE DETERMINATION OF MAGNESIUM IN BLOOD-SERUM

A flow injection configuration for the spectrofluorimetric determinati on of magnesium is proposed. The method is based on the formation of a strongly fluorescent complex of magnesium ion with 2-hydroxy-1-naphth aldehyde salicyloylhydrazone in alkaline, aqueous-ethanolic (50% v/v) solutions. The optimal chemical conditions for complex formation in th e mixed solvent were studied and the flow injection manifold was optim ized and used for the determination of magnesium in 1000-fold diluted serum samples without any other pre-treatment. The measurement through put was 120 h(-1). The detection limit of the method was 2 mu g l(-1) (2 mg l(-1) for serum). The concentration range of application is 4.8- 120 mu g l(-1) (0.2-5.0 mu mol l(-1)). Within-run relative standard de viations for the method at 4.8, 24 and 120 mu g l(-1) of magnesium wer e 3.5, 1.2 and 0.7%, respectively. Analytical recoveries range from 96 .2 to 102% (mean 98.8%).