1.1 ,This test method covers the determination of anionic impurities in 50 ,% caustic soda (sodium hydroxide) and 50 ,% caustic potash (potassium hydroxide) solutions using ion chromatography (IC). Anions that can be determined at concentrations of approximately 0.1 to 1000 ug/g (ppm) include: bromide, chlorate, chloride, fluoride, nitrate, phosphate, and sulfate.