Indirect flame atomic absorption detection for the liquid chromatographic separation of alkaline metals

Alkaline metals and ammonium ion are separated by cationic exchange liquid chromatography using a 60 g ml^–1 aqueous copper solution as the mobile phase at 1.5 ml min^–1. Detection is carried out by measuring copper with an atomic absorption spectrometer directly interfaced to the chromatograph. A simple T-piece is used to compensate the difference between the nebulizer uptake rate and the chromatographic flow-rate with air. The method is applicable to the analysis of alkaline metals and ammonium in waters. Average recovery (n = 16) was 100.3 ± 4.0%.