SPECTROPHOTOMETRIC STUDY OF THE INTERACTION OF SOME HYDROXYANTHRAQUINONES (HAQS) WITH MAGNESIUM(II) IN A CATIONIC MICELLE

Six different hydroxyanthraquinones (HAQs) in aqueous micellar (cation ic, anionic and non-ionic) media were tested as effective and selectiv e chelators for the MgII ion in alkaline conditions. Of these 1,4 and 1,8-dihydroxyanthraquinones were found to effectively bind to MgII ion s and were useful for the ppm level spectral determination of MgII ion . The MgII ion forms 1:1 and 1:2 chelates with 1,4-and 1,8-dihydroxyan thraquinones, respectively, which have maximum absorption at 610 and 5 75 nm, respectively. MgII can be determined in the presence of a large excess of foreign ions including the CaII ion. The statistical analys is of the results, apparent pK(a), expected bathchromic shift of the r eagent absorption, molar absorptivity change and electronic spectra in various organized media are discussed.