GB/T 11200.1-2006
Sodium hydroxide for industrial use - Determination of sodium chlorate content - O-Tolidine spectrometric method
GB/T 4348.3-1984
Sodium hydroxide for industrial use--Determination of iron content--o-phenanthroline photometric method
DL 425.4-1991
GB/T 11200.1-1989
Membrane process sodium hydroxide--Determination of sodium chlorate content--o-Tolidine spectrometric method
ISO 1897-4:1977
Phenol, o-cresol, m-cresol, p-cresol, cresylic acid and xylenols for industrial use — Methods of test — Part 4: Visual test for impurities insoluble in sodium hydroxide solution (Excluding cresylic acid and xylenols)