原子吸收光谱法及火焰光度法测定钠时几种醇类溶剂的影响

在以Zeiss Ⅲ型火焰光度计改装成的装置上,以相同条件观察了不同浓度的甲醇、乙醇、丙醇对钠的原子吸收值及发射值的增强作用。测量了各种醇类、水溶液的表面张力及粘度,喷雾器的喷雾率及有效喷雾率,和火焰温度,并对醇类的增强作用的机理作了一些探讨。实验及计算结果表明,虽然有效喷雾率是决定吸收值增强作用的主要因素,但对于电离电位较低的碱金属,由于火焰温度降低而引起的电离度的减小亦起一定的作用,对于发射值的增强。除了有效喷雾率和电离度之外。还要考虑Boltznman因子e^(E_i/k_T)。

EFFECTS OF ALCOHOLS ON ATOMIC-ABSORPTION AND EMISSION FLAME PHOTOMETRIC DETERMINATION OF SODIUM

The enhancements of sodium atomic-absorption and emission by methyl-, ethyl-, and propyl-alcohol of various concentrations were studied under identical conditions with a modified Zeiss Model Ⅲ flame photometer. The spray rate, the effective spray rate (i.e., the amount of spray reaching the flame per unit time), the flame temperature, and the surface tension and viscosity for various alcohol-water solutions were measured, and a possible mechanism of the enhancements was suggested. According to this mechanism, it was shown that although the enhancement in absorption results mainly from an increase in the effective spray rate, but for alkali metals, which have low ionization potentials, the reduction of the degree of ionization due to the lowering of the flame temperature also plays a definite role. As for the enhancement in emission, it was shown that in addition to the changes in effective spray rate and degree of ionization, the change in the Boltzmann factor exp(-E_i/kT) should also be taken into account.