EPA-NERL: 547:  Glyphosate in Water Using HPLC w/ Post Column Derivitization

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Determination of Glyphosate in Drinking Water by Direct-Aqueous-Injection HPLC, Post Column Derivitization, and Fluorescence Detection
Current Revision
July 1990
High Performance Chromatography with Post Column Derivitization and Fluorescence Detection
Method Subcategory
Method Source
  Methods for the Determination of Organic Compounds in Drinking Water - Supplement I (EPA/600/4-90-020)
Brief Method Summary
An aliquot of a filtered water sample is injected into a cation exchange high performance liquid chromatography (HPLC) column. Separation is achieved by using an isocratic elution. After elution from the analytical column, the analyte is oxidized with calcium hypochlorite. The product (glycine) is then coupled with o-phthalaldehyde-2-mercaptoethanol complex at 38oC to give a derivative fluorophor (post-column derivitization). The concentration of glyphosate eluted from the HPLC column is measured by detecting the fluorescence of the derivative with a fluorometer.
Scope and Application
This method determines glyphosate in drinking water.
Applicable Concentration Range
Not specified in method. Range differs depending on matrix and instrumentation.

(A) Glassware contamination: Thoroughly clean glassware, including baking or solvent rinse.

(B) Reagent contamination: Use high purity reagents.

Quality Control Requirements

Initial demonstration of laboratory capability, followed by analysis of laboratory reagent blanks (LRBs), laboratory fortified matrix samples, laboratory fortified blanks (LFBs), and QC samples. Initial demonstration of laboratory capability includes analysis of LFBs at an analyte concentration of 250 ug/L. A MDL also must be determined.

Sample Handling

Collect samples in glass containers following conventional sampling practices. Dechlorinate samples with 100 mg/L of sodium thiosulfate. Store samples at 4oC away from light until analysis.

Maximum Holding Time

14 days generally; up to 18 months for glyphosate in frozen samples.

Relative Cost
$201 to $400
Sample Preparation Methods