EPA-NERL: 325.1:  Chloride by Automated Colorimetry

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Chloride (Colorimetric, Automated Ferricyanide AI)
Current Revision
Issued 1971
Media
WATER
Instrumentation
Automated Spectrophotometer
Method Subcategory
Inorganic
Method Source
  EPA-NERL
Citation
  Methods for the Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/4-79/020)
Brief Method Summary
Thiocyanate ion (SCN) is liberated from mercuric thiocyanate through sequestration of mercury by chloride ion to form un-ionized mercuric chloride. In the presence of ferric ion, the liberated SCN forms a highly colored ferric thiocyanate in concentration proportional to the original chloride concentration. Measurements of the colored complex are made using an automated spectrophotometer.
Scope and Application
This automated method determines chloride in drinking, surface, and saline waters; domestic and industrial wastes.
Applicable Concentration Range
1 - 250 mg/L
Interferences
No significant interferences.
Quality Control Requirements
None.
Sample Handling
No special requirements.
Maximum Holding Time
28 days (MCAWW, Table 1).
Relative Cost
Less than $50
Sample Preparation Methods