Determination of Zinc in Water Sample Using Graphite Furnace Atomic Absorption Spectrometry

A method is described for the determination of zinc concentrations in the range of μg· L-1 -mg · L-1 in water samples by graphite furnace atomic absorption spectrometry (GFAAS). The determination of low concentration zinc by flame atomic absorption spectrometry is complicated due to the requirement of sample enrichment, while the determination of zinc by GFAAS is apt to contamination during sample reparation due to the high sensitivity of GFAAS. In our experiment, the sample preparation is a simple dilution with a diluent containing 20% ( ) alcohol which decreases blank signal level and achieves better precision. The calibration curve, established with matrix-matched standards, is linear for concentrations up to 20 μg·L-1, which is achieved by adjusting the inner gas flow rate of N2 to 0.5 L·min-1 at atomization temperrature. The limit of detection was 0.098 μg·L-1 (n = 10) for zinc in water, and the relative standard deviations were between 0.55%-5.9%. The method was applied to samples of spring water, river water, and water supply with good results.