This International Standard specifies a dithizone photometric method for the determination of the mercury content of sodium hydroxide for industrial use.
The method is applicable to liquid or solid products having mer-cury (Hg) contents greater than 0,05 mg/kg.
NOTE —The alternative flameless atomic absorption spectrometric method for the determination of mercury content, specified in ISO 5993, is intended for use in laboratories where such equipment is available.