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本文描述了以氩/氢混合气体作保护气体,测定环境和生物样品中痕量镉的石墨炉原子吸收法。实验证明,与纯氩气作保护气体相比较用氩/氢混合气体作保护气体,能够降低镉的原子化温度(100℃),并且减少基体物质如MgCl_2和NaClO_4的干扰。这种改善氯化物和高氯酸盐基体干扰的机理,主要是由于氢的存在与基体中的氯形成高离解能的氯化氢,从而避免了通常在镉原子化之前形成易挥发的氯化镉而损失。用本方法测定了七种标准参考物质,结果与标准值一致,证明方法是可靠的。
This paper describes a graphite furnace atomic absorption method for the determination of trace amounts of cadmium in environment and biological samples using argon / hydrogen gas as the shielding gas. Experiments show that compared with the pure Argon gas, the Argon / Hydrogen gas mixture can reduce the atomization temperature of Cd (100 ℃) and reduce the interference of matrix materials such as MgCl_2 and NaClO_4. This mechanism for improving the interference of the chloride and perchlorate substrates is mainly due to the formation of highly dissociated hydrogen chloride from the chloride in the substrate due to the presence of hydrogen thereby avoiding the formation of readily volatile cadmium chloride, loss. Seven standard reference materials were determined by this method, and the results were consistent with the standard values, which proves that the method is reliable.