標準號：ISO 2833-1973
中文標準名稱：工業用氟化鈉 氟含量的測定 威拉德-溫特爾改進法
英文標準名稱：Sodium fluoride for industrial use; Determination of fluorine content; Modified Willard-Winter method
標準類型：G10
發布日期：1999/12/31 12:00:00
實施日期：1999/12/31 12:00:00
中國標準分類號：G10
國際標準分類號：71.060.50
適用范圍：The principle consists in separation of the fluorine from a test portion by distillation with sulphuric acid or perchloric acid. Titration with thorium nitrate solution using sodium alizarinsuphonate and methylene blue as indicators. Alternatively the thorium nitrate titration may be carried out using sodium alizarinsuphonate alone as indicator, the end-point being determined spectrophotometrically under carefully defined conditions. The absorbance at a wavelength of 525 nm shall reach the arbitrary value of 0.6. Has also been approved by the IUPAC.