DETERMINATION OF TOTAL MAGNESIUM IN SERUM USING A COMMERCIAL SPECTROPHOTOMETRIC KIT AND THE BETA-CORRECTION METHOD

Among spectrophotometric methods for the determination of magnesium in biological fluids the most popular in clinical laboratories are the p rocedures based on the reaction of magnesium with coloured dyes: Calma gite ydroxy)-5-methylphenylazo-1-naphthalene-5-sulfonic acid] and Mago n [sodium do)-naphtalene-1'-(2-hydroxybenzene-5-sulfonate)]. There. ar e commercially available kits for such routine determination which con tain solutions of dye, buffer and a masking agent. However the quantit ation procedure recommended in such tests is based on the simple calib ration technique and the use of a standard aqueous magnesium solution. In order to improve the accuracy and sensitivity of magnesium determi nation in serum, in this paper some serum components were added to the standard Mg solution used for the calibration, and the beta-correctio n spectrophotometric procedure was applied. The results of magnesium d etermination in the reference- and normal serum samples obtained using the proposed procedures were compared with the results obtained by th e atomic absorption spectrometry. The analytical characteristics for t he spectrophotometric determination of magnesium with Magon as the com plexing agent are given.