Determination of magnesium and calcium in 30% sodium chloride by ion chromatography with on-line matrix elimination

Ion chromatography with on-line matrix elimination reliably determines low microgram-per-litre amounts of magnesium and calcium in brine (30% NaCl). Magnesium and calcium from 100 mu l of brine were concentrated on a metal-chelating resin containing iminodiacetate functional groups. After excess sodium was rinsed away, magnesium and calcium were eluted from the metal-chelating column, separated on a cation-exchange column, and detected by suppressed conductivity. This method was reproducible at 5 mu g/l magnesium and calcium in brine. (C) 1998 Elsevier Science B.V. Ail rights reserved.