Flow injection spectrofluorimetric method for the determination of magnesium in blood serum

Abstract

A flow injection configuration for the spectrofluorimetric determination of magnesium is proposed. The method is based on the formation of a strongly fluorescent complex of magnesium ion with 2-hydroxy-1-naphthaldehyde salicyloylhydrazone in alkaline, aqueous–ethanolic (50% v/v) solutions. The optimal chemical conditions for complex formation in the mixed solvent were studied and the flow injection manifold was optimized and used for the determination of magnesium in 1000-fold diluted serum samples without any other pre-treatment. The measurement throughput was 120 h^–1. The detection limit of the method was 2 µg l^–1(2 mg l^–1 for serum). The concentration range of application is 4.8–120 µg l^–1(0.2–5.0 µmol l^–1). Within-run relative standard deviations for the method at 4.8, 24 and 120 µg l^–1 of magnesium were 3.5, 1.2 and 0.7%, respectively. Analytical recoveries range from 96.2 to 102%(mean 98.8%).