GF-AAS Determination of Microamounts of Barium in Natural Water with Zeeman Effect Background Correction

GF-AAS,using calcium chloride as matrix modifier and tungsten coated graphite tube,was applied in the determination of microamounts of barium in natural water.Through treatment of the graphite tube with potassium tungstate,a layer of tungsten carbide was formed and coated on the surface of the tube,by which the sensitivity and precision of the determination were improved,as well as the service life of the graphite tube was remarkably prolonged.By adding calcium salt solution of high concentration to both the sample and standard solutions,the interference of calcium to barium was overcame.Detection limit (3σ) of the method was found to be 33.4 pg.Barium contents in 3 water samples were determined by this method,recovery and precision were tested,giving values of RSD′s (n=6) in the range of 2.3%-6.5% and of recovery in the range of 101.0%-107.2%.