GB-T 11892-1989 Water quality-Determination of permanganate index
GBT 7494-1987 Water quality-Determlnatlon of anionic surfactants-Methylene blue spectrophotometric method
GB 7477-1987 Water quallty-Determination of the sum ofcalclum and magnesium-EDTA titrimetric method
GB 7489-1989 Water quality-Determinat fon of dissolved oxygen-lodometric method

