CONTRIBUTIONS TO SPECTROPHOTOMETRIC DETERMINATION OF CALCIUM AND MAGNESIUM IN PHARMACEUTICALS.
L.L. RUS*, M. BOJIŢĂ
UMF “Iuliu Haţieganu” – Cluj-Napoca, Faculty of Pharmacy, Emil Isac Street, No. 13, 400349, Drugs Control Departament
*corresponding author: lrus@umfcluj.ro

Abstract:

A spectrophotometric method for determination of calcium and magnesium in pharmaceuticals is proposed. The determination is based on the blue colour developed by the reaction of calcium and magnesium with Methylthymol Blue (MTB) at pH 11(NH₄⁺- NH3 buffer). The method of continuous variations (JOB`s method) was used in order to determine the ratio combination of complex ions Ca-MTB and Mg-MTB. The method was applied to the analysis of calcium and magnesium in pharmaceuticals. Results were compared with those obtained by complexonometry. Recoveries were higher than 98%..

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