TRACE-LEVEL DETERMINATION OF BARIUM IN BR INES USING LOW AND HIGH-PRESSURE FLOW SYSTEMS FOR PRECONCENTRATION MATRIX SEPARATION AND SAMPLE INTRODUCTION IN FLAME ATOMIC-ABSORPTION SPECTROMETRY (FAAS)/

Traces of barium in sodium chloride brines were assessed satisfactoril y by Hydraulic High-Pressure Nebulization Flame Atomic Absorption Spec trometry (HHPNFAAS). Barium was preconcentrated 30 times in a short C1 8 RP column (length 1 cm) using xylenol orange as chelating agent and tetrbutylammonium acetate as ion pair former. A low pressure system wa s used in the preconcentration step followed by a high pressure system was used in the elution step. No interferences were observed in bariu m absorption when solution samples of sodium chloride between 2 and 25 % (w/v) were analyzed. The calibration curve was linear up to 0.5 mu g /mL, with a detection limit of 0.01 mu g/mL (3s(blank), N = 14). The m ethodology was applied in the determination of barium at trace levels in samples of sodium chloride used in the production of chlorine and s odium hydroxide.