规定方法的原理是向样品中添加氯化铯溶液作为电离抑制剂，将样品直接吸入原子吸收光谱仪的空气/乙炔火焰中，并在589,0 nm波长下测量吸光度。适用于钾质量浓度在5 mg/l至50 mg/l范围内的水样。如果选择了其他稀释因子，该范围可以扩大。

The principle of the method specified is adding a caesium chloride solution to the sample as an ionization suppressant, aspirating the sample directly into the air/acetylene flame of an atomic absorption spectrometer and measuring the absorbance at a wavelength of 589,0 nm. Applies to water samples with a mass concentration of potassium in the range from 5 mg/l to 50 mg/l. This range can be extended if other dilution factors are chosen.