Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of methylene blue active substances by spectrophotometry
Open-File Report
95-189
By: Mark R. Burkhardt, Pete J. Cinotto, Galen W. Frahm, Mark T. Woodworth, and Jeffrey W. Pritt
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Abstract
A method for the determination of methylene blue active substances in whole-water samples by liquid-liquid extraction and spectrophotometric detection is described. Sulfate and sulfonate-based surfectants are reacted with methylene blue to form a blue-colored complex. The complex is extracted into chloroform, back-washed with an acidified phosphate-based buffer solution, and measured against external standards with a probe spectrophotometer. The method detection limt for routine analysis is 0.02 milligram per liter. The precision is plus/minus 10 percent relative standard deviation. The positive bias from nitrate and chloride and U.S. Geological Survey method O-3111-83 for methylene blue active substances is minized by adding a back-washing step.
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of methylene blue active substances by spectrophotometry |
| Series title | Open-File Report |
| Series number | 95-189 |
| DOI | 10.3133/ofr95189 |
| Year Published | 1995 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Contributing office(s) | National Water Quality Laboratory |
| Description | iv, 16 p. |
| Google Analytic Metrics | Metrics page |