MBAS active substances

The primary biodegradation grades of secondary alkanesulfonates measured by different tests are distinctly above 90%. In the OECD Confirmatory Test (sewage treatment plant simulation test), the biodegradability is 99% (decrease in MBAS, the methylene blue active substance). 

Alcohol and alcohol ether sulfates are commonly considered as extremely rapid in primary biodegradation. The ester linkage in the molecule of these substances, prone to chemical hydrolysis in acid media, was considered the main reason for the rapid degradation. The hydrolysis of linear primary alcohol sulfates by bacterial enzymes is very easy and has been demonstrated in vitro. Since the direct consequence of this hydrolysis is the loss of surfactant properties, the primary biodegradation, determined by the methylene blue active substance analysis (MBAS), appears to be very rapid. However, the biodegradation of alcohol sulfates cannot be explained by this theory alone as it was proven by Hammerton in 1955 that other alcohol sulfates were highly resistant [386,387]. 

Active matter (anionic surfactant) in AOS consists of alkene- and hydroxy-alkanemonosulfonates, as well as small amounts of disulfonates. Active matter (AM) content is usually expressed as milliequivalents per 100 grams, or as weight percent. Three methods are available for the determination of AM in AOS calculation by difference, the two-phase titration such as methylene blue-active substances (MBAS) and by potentiometric titration with cationic. The calculation method has a number of inherent error factors. The two-phase titration methods may not be completely quantitative and can yield values differing by several percent from those obtained from the total sulfur content. These methods employ trichloromethane, the effects from which the analyst must be protected. The best method for routine use is probably the potentiometric titration method but this requires the availability of more expensive equipment. 

Functional loss or loss of methylene blue active substance (MBAS) has been studied by Kravetz et al. [141]. These authors have shown 98-99% disappearance of AOS and AES starting materials by the third day of the study. It was also observed that LAS degrades at significantly slower rates than AOS in MBAS tests. 

GAC Granular activated carbon MBAS Methyl blue active substances MMO Methane mono-oxygenase enzyme MSW Municipal solid waste... 

Uchiyama [11] applied this method to the determination of fluorescent whitening agents and alkyl benzenesulphonates and also methylene blue active substances in bottom sediment samples taken in a lake. The muds were filtered off with a suction filter and frozen until analyzed. About 20g of wet bottom mud was extracted three times with a methanol-benzene (1 1) mixture. After the solvent was evaporated using a water bath, the residue was dissolved in hot water and this solution used for analysis. Table 10.2 shows the analytical results for methylene blue active substances (MBAS), alkyl benzene-sulphonate (ABS), and fluorescent whitening agent (FWA) in bottom sediments. 

Kimerle [27] reviewed the ecotoxicology of LAS focusing on the results rather than on the method of analysis, for which the author referred to the review undertaken by Painter and Zabel [30], alluding only to two papers on biota sample preparation. Litz et al. [31] determined the concentration of LAS in rye grass by Azure A active substances (AzAAS). AzAAS is a non-specific colorimetric method, which has not been used as frequently as MBAS (see Chapter 3.1). Briefly, it consists of the formation of an ion association complex with a dyed solution of Azure A (cationic). The complex formed is solvent-extractable and is separated from unreacted dye prior to colour measurement. 

DEQ DM DTD MAC EO FADA LAB LAS M MBAS MCPEG Lever s diester quat dialkyldimethyl ammonium ditallow dimethylammonium chloride ethylene oxide fatty acid diethanolamide linear alkylbenzene linear alkylbenzene sulfonate R3S1O0.5 methylene blue active substances mono carboxylated PEG... 

Measurement of Biodegradation. Numerous studies have documented the aerobic biodegradability of various AS compounds (see ref. 12). Most of these studies used methylene blue active substance (MBAS) and other colorimetric determinations, change in surface tension, foaming capacity, and sulfate formation as an indication of primary AS degradation. 

LAS Treatability and Environmental Concentrations. The removal of LAS during sewage treatment was confirmed by monitoring studies in both the United States and Europe. Numerous studies reported anionic surfactant concentrations in surface waters measured by nonspecific analytical techniques such as methylene blue active substance (MBAS). However, the correlation between MBAS and LAS concentrations determined by spe-... 

Such anionic surfactants that form ion pairs with methylene blue and that are extractable with chloroform are known as Methylene Blue Active Substances (MBAS). Other cationic dyes, such as crystal violet dye, may be used instead of methylene blue. Extraction of such an ion-pair complex into benzene has been reported (Hach, 1989). Detection Limit = 10 pg/L. 

The laboratory determination of surfactants involves using methylene blue. This is done by measuring the color change in a standard solution of the dye. The surfactant can be measured using methylene blue, so its other name is methylene blue active substance (MBAS). 

AOAC Association of Official Analytical MBAS Methylene blue active substance... 

The same relates to the analytical methods, where for anionic, nonionic and cationic surfactants, various colorimetric procedures (MBAS, bismuth active substance(s) (BiAS), and disulfine blue active substance(s) (DSBAS)) were introduced. Since these methods analyse only the loss of surface-activity or primary degradation, other analytical approaches have been employed in the last 10 years in order to characterize the total or ultimate degradation. These include methods such as high performance liquid chromatography (HPLC), gas chromatography (GC) GC/mass spectrometry (MS), and the measurement of total organic carbon (TOC) and chemical oxygen demand (COD). 

Photometric determination of anionic detergents (surfactants) with methylene blue (Methylene blue active substances, MBAS)... 

Combustion-infrared, persulfate-ultraviolet oxidation, wet oxidation Adsorption-pyrolysis-titrimetric method Partition-gravimetric, partition-infrared, extraction Extraction (total phenols), distillation (volatiles), colorimetry Separation by sublation, methylene blue active substances (MBAS), anionics and cobalt thiocyanate active susbstances (CTAS), nonionic surfactants Chromatographic, distillation... 

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