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    微波消解-石墨炉原子吸收光谱法测定固定污染源废气样品中铜、镍、镉的含量

    Determination of Copper, Nickel and Cadmium in Waste Gas Samples from Stationary Pollution Sources by Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion

    • 摘要: 用滤筒采集固定污染源废气样品,将滤筒剪碎,置于微波消解管中,加入体积比3:1的盐酸-硝酸混合液5.0 mL和水20.0 mL,于200℃消解15 min。在所得消解液中加入水10 mL,静置0.5 h进行浸提,过滤,用水定容至50 mL。所得样品溶液采用石墨炉原子吸收光谱法测定其中铜、镍、镉的含量。铜、镍、镉3种元素优化的测定条件如下:灰化温度依次为1 100,1 200,500℃,灰化时间均为20 s,原子化温度依次为2 000,2 400,1 500℃,原子化时间依次为5,5,4 s。结果表明:铜、镍、镉的质量浓度在一定范围内与其对应的吸光度值呈线性关系,检出限(3.143s)依次为2,3,0.06 μg·L-1。用此法测定煤飞灰中重金属成分分析标准物质(总量)(RMU010),测定值与认定值基本一致。平行测定某实际煤飞灰样品6次,测定值的相对标准偏差为2.6%~7.0%。采集某固定污染源废气样品7个,按本方法测定,测定值的相对标准偏差小于20%,说明采集方法具有一定稳定性。

       

      Abstract: Waste gas samples from stationary pollution sources were collected by filter cartridges, and the filter cartridges were cut into pieces and placed into microwave digestion tubes. 5.0 mL of a mixture of hydrochloric acid and nitric acid at a volume ratio of 3:1 and 20.0 mL of water were added, and the mixture was digested at 200℃ for 15 min. 10 mL of water was added into the digestion solution obtained, settling for 0.5 h. After filtration, the solution was made its volume up to 50 mL with water. Copper, nickel and cadmium in the sample solution were determined by graphite furnace atomic absorption spectrometry. The optimized determination conditions of copper, nickel and cadmium were as follows:the ashing temperatures were 1 100, 1 200, 500℃, with the same ashing time of 20 s; the atomization temperatures were 2 000, 2 400, 1 500℃, with the atomization time of 5, 5, 4 s, respectively. As shown by the results, linear relationships between values of absorbance and mass concentration of copper, nickel and cadmium were found in definite ranges, with detection limits (3.143s) of 2, 3, 0.06 μg·L-1, respectively. This method was applied for determination of the reference material (total amount) (RMU010) for heavy metal composition analysis in coal fly ash, and the determined values were basically consistent with the certified values. An actual coal fly ash sample was determined 6 times in parallel, with RSDs of the determined values in the range of 2.6%-7.0%. Seven waste gas samples from a stationary pollution source were collected and determined by this method, with RSDs of the determined values less than 20%, and it was shown that the collection method had certain stability.

       

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