Standard Methods: 4500-F-C:  Ion-Selective Electrode Method

  • Summary
  • Analytes
  • Revisions
  • Data and Sites
Official Method Name
 Ion-Selective Electrode Method
Current Revision
Standard Methods Online
Media
 WATER
Instrumentation
 Ion Selective Electrode
Method Subcategory
 Inorganic
Method Source
  Standard Methods
Citation
  Standard Methods Online - Standard Methods for the Examination of Water and Wastewater
Brief Method Summary
 The fluoride electrode is an ion-selective sensor. The key element in the fluoride electrode is the laser-type doped lanthanum fluoride crystal across which a potential is established by fluoride solutions of different concentrtations. The crystal contacts the sample solution at one face and an internal reference soluton at the other. The fluoride electrode can be used with a standard calomel reference electrode and almost any modern pH meter having an expanded millivolt scale.
Scope and Application
 This method covers the determination of fluoride in drinking water.
Applicable Concentration Range
 0.1 to > 10 mg F-/L
Interferences
 Positive error from alkalinity. Negative error from aluminum, iron, and sulfate
Quality Control Requirements
 Analysis of standards for accuracy check
Sample Handling
 Collect samples in polyethylene bottles. Glass bottles are satisfactory if previously they have not contained high-fluoride solutions. Rinse bottle with a portion of sample.
Maximum Holding Time
 28 days
Relative Cost
 Less than $50
Sample Preparation Methods
 4500-F- B
WHO WE ARE
  • NWQMC
  • USGS
  • EPA
LEGAL