1 Application Scope
This standard specifies fluorine reagents spectrophotometry for determination of fluoride in surface water, underground water and industrial wastewater.
This standard is applicable to determination of fluoride in surface water, underground water and industrial wastewater.
For the purpose of this method, the detection limit is 0.02 mg/L and the lower determination limit is 0.08 mg/L.
2 Method Principle
Make fluorinion reacted with fluorine reagents and lanthanum nitrate in acetate buffer medium (pH=4.1), producing blue ternary complex whose absorbance at a wave length of 620nm is in direct proportion to fluorinion concentration and then determine quantitatively the fluoride (F-).
3 Reagents and Materials
Unless otherwise specified, the reagents adopted in this standard shall all be analytically pure chemical agents complying with the national standard, and the water for experiment shall be deionized water or fluoride-free distilled water newly prepared.
3.1 Hydrochloric acid solution: c=1 mol/L.
Take 8.4ml of hydrochloric acid into 100ml of deionized water.
3.2 Sodium hydroxide solution: c=1 mol/L.
Weigh 4g of sodium hydroxide and dissolve it into 100mL water.
3.3 Acetone (CH3COCH3).
3.4 Sulfuric acid (H2SO4): ρ20=1.84 g/ml.
Foreword i
1 Application Scope
2 Method Principle
3 Reagents and Materials
4 Apparatus
5 Interference and Its Elimination
6 Sample
7 Analytical Procedures
8 Result Calculation
9 Precision and Accuracy
Annex A (Normative) Water Quality Determination of Fluoride Pretreatment of Samples Containing Interfering Ion
