Spectrophotometric determination of magnesium in pharmaceutical preparations by cost-effective sequential injection analysis

摘要: A simple and rapid, inexpensive spectrophotometric method was proposed for magnesium assay in pharmaceutical preparations by sequential injection analysis (SIA). The is based on the reaction between o-cresolphthalein complexone (CPC) Mg(II) alkaline media, yielding a pink colored complex with absorption maximum at 570nm. Since formation constant Ca-CPC Mg-CPC similar, initially sample/standard solution aspirated into holding coil followed mixture of masking-buffer solutions. This done because masking calcium should be accomplished before complexation. Then reagent introduced to produce complex, which measured spectrophotometrically In this way interference reduced. Furthermore, all parameters that affect were evaluated. calibration curve linear over range 0-20mgl(-1) detection limit 0.24mgl(-1). sample throughput 80 samples per hour relative standard deviation <2.0% achieved. successfully applied three different compositions (tablets). results found good agreement manual flame atomic spectrophotometry (FAAS) UV-Vis methods claimed values manufactures. t-test shows no significant difference 95% confidence level.