Detergents (anionic surfactants, MBAS)
 
 
Visual Kits
Range MDL Method Kit Catalog No. Refill Catalog No.
0-3 ppm 0.125 ppm Methylene Blue K-9400 R-9400
0-1400 ppm 100 ppm Methylene Blue K-9404 R-9404
Instrumental Kits
Range Method Kit Catalog No.
0.25-2.50 ppm Methylene Blue I-2017

Method

References: USEPA Methods for Chemical Analysis of Water and Wastes, Method 425.1 (1983). APHA Standard Methods, 21st ed., Method 5540 C (2005). ASTM D 2330-02 , Methylene Blue Active Substances.


Detergents can be introduced into the water supply by industry, soap manufacturers, and private households. Environmental analysts often include a determination of anionic detergents when assessing surface water pollution.

 

  The methylene blue active substances (MBAS) method is used in a 3-minute procedure to measure anionic detergents in the 0-3 ppm (mg/L) range. The procedure features a unique extraction/sampling technique that eliminates several steps required in other test procedures and provides increased sensitivity.

 

  Anionic detergents react with methylene blue to form a blue-colored complex that is extracted into an immiscible organic solvent. Results are expressed in ppm (mg/L) as linear alkylbenzene sulfonate (LAS), equivalent weight 325.

 

  Shelf-life: eight months. We recommend stocking quantities that will be used within seven months.