HClO_4和NH_4ClO_4对钒和铬的干扰及其机理——石墨炉原子化器中原子化过程的研究(Ⅷ)

Mechanism of Interference of Pcrchloric Acid and Ammonium Perchlorate with Absorption Signal of Vanadium and Chromium in the Graphite Furnace ——The Study of Atomization Process in the Graphite Furnace Atomizer (Ⅷ)

研究了HClO_4对V和Cr吸收信号的干忧。实验结果表明,HClO_4对V和Cr吸收信号有明显的抑制作用,并存在残留HClO_4的干枕,当预加热温度达1900℃和1500℃时,残留HClO_4对V和Cr的干扰可除去,在涂钨热解石墨管中HClO_4不干扰Cf吸收信号,NH_4ClO_4对V和Cr吸收信号亦有抑制作用,但不存在残留物的干扰,EDTA铵盐可消除HClO_4对V和Cr的干扰。

The influence of perchloric acid on absorption signal of vanadium and chromium in the graphite furnace was studied in detail. A suppression effect of perchloric acid on the absorption signal of vanadium and chromium was found. The interference of residual perchloric acid was eliminated by thermal pretreatment at temperature up to 1900 C and 1500 C for vanadium and chromium, respectively. There is no interference of perchloric acid with absorption signal of chromium in the pyrolytic tube coated with tungsten. The interference of perchloric acid can be removed by adding ammonium salt of EDTA prior to the decomposition of perchloric acid. It was found a suppression effect of ammonium perchlorate on absorption signal of vanadium and chromium exists also. The mechanism of variant interference of perchloric acid and ammonium perchlorate with vanadium and chromium is discussed as well in this paper.