石墨炉原子吸收法测定水样中的痕量锌

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

文章对锌含量在μg·mL^(-1)～mg·L^(-1)范围的水样品的石墨炉原子吸收法测定进行了研究。通常由于在石墨炉原子吸收法测定中,由于锌的灵敏度很高使制样过程易受到污染,而火焰原子吸收法测定需较繁杂的富集。通过在样品加入乙醇降低空白值和改进精密度,调节仪器条件的内气流为0.5L·min^(-1)以降低锌的灵敏度,使方法线性范围达到0～20μg·L^(-1)。本法相对标准偏差为0.5％～5.9％之间,检测限为0.098μg·L^(-1)。应用于天然河水、自来水及瓶装矿泉水中锌的测定,结果令人满意。

A method is described for the determination of zinc concentrations in the range of mug(.) 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% (phi) alcohol which decreases blank signal level and achieves better precision. The calibration curve, established with matrix-matched standards, is linear for concentrations up to 20mug(.)L(-1), which is achieved by adjusting the inner gas flow rate of N-2 to 0.5L(.)min(-1) at atomization temperrature. The limit of detection was 0.098 mug(.)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.