Disulfine blue active substances

DIN German Standard Method for the Examination of Water, Waste Water and Sludge General Measures of Elfects and Substances (Group H). (A) Determination of Methylene Blue Active Substances (H23-1), (B) Determination of Bismuth Active Substances (H23-2), (C) Determination of the Disulfine Blue Active Substances (H20). VCH, Weinheim, Germany, 1992. 

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). 

Cationic surfactants form ion pairs with suitable anionic dyes that are extractable into organic solvents. The anionic dye most widely used is disulfineblue (DBAS disulfine blue active substances). After extraction of the ion pair into chloroform, the extinction is determined at 628 nm. The presence of anionic surfactants results in serious interferences, therefore they have to be separated by anion exchange before the addition of disulfine blue [52,53]. The determination of cationic surfactants is hampered by some problems not encountered with MBAS. In particular, cationic surfactants are strongly adsorbed to almost any surface, so that, all the apparatus has to be specially pretreated. 

---