Anionic Surfactants as MBAS

By SM 5540C

Scope:

The MBAS method has been applied successfully to drinking water samples. In wastewater, industrial wastes, and sludge, numerous materials normally present can interfere seriously if direct determination of MBAS is attempted. Most nonsurfactant aqueous-phase interferences can be removed by sublation.

Methylene blue active substances (MBAS) bring about the transfer of methylene blue, a cationic dye, from an aqueous solution into an immiscible organic liquid upon equilibration. This occurs through ion pair formation by the MBAS anion and the methylene blue cation. The intensity of the resulting blue color in the organic phase is a measure of MBAS. The method comprises three successive extractions from acid aqueous medium containing excess methylene blue into chloroform (CHCl3), followed by an aqueous backwash and measurement of the blue color in the CHCl3 by spectrophotometry at 652 nm.

Method Data

Method 200.8
Hold Time6 months from preservation to analysis,
Preservationpreserve with HNO3 to pH <2 within two weeks of collection. Dissolve elements: acidfy the filtrate with HNO3 to pH <2 immediately after filtration. Solid samples should be kept at 4°C.
Sample Volume250mL HDPE bottle
Collection MethodGrab sampling
InstrumentationICP/MS PerkinElmer NexION 350X
Method Refernce200.8

Analyte List

AnalyteFormulaCAS Number
AluminumAl7429-90-5
AntimonySb7440-36-0
ArsenicAs7440-38-2
BariumBa7440-39-3
BerylliumBe7440-41-7
CadmiumCd7440-43-9
CalciumCa7440-70-2
ChromiumCr7440-47-3
CobaltCo7440-48-4
CopperCu7440-50-8
IronFe7439-89-6
LeadPb7439-92-1
MagnesiumMg7439-95-4
ManganeseMn7439-96-5
MolybdenumMo7439-98-7
NickelNi7440-02-0
PotassiumK7440-09-07
SeleniumSe7782-49-2
SilverAg7440-22-4
SodiumNa7440-23-5
ThalliumTl7440-28-0
TitaniumTi7440-32-6
VanadiumV7440-62-2
ZincZn7440-66-6

* The typical detection limits and analytes are displayed for this particular method. Please contact Specialty Analytical if other analytes or detection limits are required in addition to the 200.8 Analyte List.

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