Methylene Blue Active Substances (MBAS)

Definition - What does Methylene Blue Active Substances (MBAS) mean?

Methylene blue active substances (MBAS) are anionic surfactants that can be detected by colometric or color reaction methods. An MBAS assay is a type of analysis that makes use of a substance called methylene blue in order to detect the existence of foaming agents, detergents as well as other anionic substances in water under testing.

With the MBAS assay method, undesirable components in water samples can be detected appropriately. This prevents water corrosion or contamination.

Corrosionpedia explains Methylene Blue Active Substances (MBAS)

Methylene blue active substances can be found in water samples. This may include substances that can cause industrial and health damage, such as:

  • Sulfonates
  • Phosphates
  • Sulfates
  • Carboxylates

Thus, early detection is vital to prevent the harmful effects of corrosive substances. This can be achieved through the MBAS assay technique.

An MBAS assay is performed by acidifying the water sample by using boric acid or similar substances. Then chloroform is added with methylene blue solution, a type of cationic dye.

The biphasic mixture that is produced is agitated in order to disperse the reagents through the organic and aqueous phases. If an anionic surfactant is found, it combines with cationic methylene blue to form a pair of ions that are extracted into the organic stage. With higher surfactant concentrations, the chloroform's color also enhances.

Since MBAS is a controlled substance that may be present in trade waste distributed to the wastewater system, techniques such as the MBAS assay can help in controlling high levels of MBAS. When not managed properly, MBAS can affect water anesthetics and even cause foaming.

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