Disulfine blue

Herring Dimidium bromide + disulfine blue 2 Hyamine 1622 183... 

The two-phase titration is based on the reaction of anionic surfactants with cations—normally large cationic surfactants—to form an ion pair. The preferred cationic is benzethonium chloride (Hyamine 1622, 1) because of the purity of the commercially available product. On neutralization of the ionic charges, the ion pair has nonpolar character and can be extracted continuously into the organic phase, e.g., chloroform, as it is formed. The reaction is monitored by addition of a water-soluble cationic dye, dimidium bromide (2), and a water-soluble anionic dye, disulfine blue (3). The cationic dye forms an extractable... 

Recently, several modifications of the two-phase titration and their precisions have been compared. The two-phase titration with the above-mentioned mixed indicator system, dimidium bromide/disulfine blue, is standardized in DGF (Deutsche Gesellschaft fur Fettforschung) and DIN methods, and is less time consuming and simpler than the standard gravimetric and extraction methods [18]. 

Gravimetric and volumetric methods are practicable for the quantitative determination of the a-sulfo fatty acid esters. Using gravimetric methods the surfactant is precipitated with p-toluidine or barium chloride [105]. The volumetric determination method is two-phase titration. In this technique different titrants and indicators are used. For the analysis of a-sulfo fatty acid esters the quaternary ammonium surfactant hyamine 1622 (p,f-octylphenoxyethyldimethyl-ammonium chloride) is used as the titrant [106]. The indicator depends on the pH value of the titration solution. Titration with a phenol red indicator is carried out at a pH of 9, methylene blue is used in acid medium [106], and a mixed indicator of a cationic (dimidium bromide) and an anionic (disulfine blue VN150) dye can be used in an acid and basic medium [105]. 

Dyes. Vital dyes have been used for many years in a variety of clinical situations. Patent blue V (also called E131, Acid blue 3, Disulfine blue) and Isosulfan blue (also called Patent blue violet or Lymphazurine), belong to the group of triarylmethane dyes and are the most commonly used [24]. Reports of IgE-dependent anaphylaxis arise. Anaphylactic reactions involving methylene blue seems to be very rare, however, several reports of sensitization to both Patent blue and methylene blue have previously been reported. 

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 titration end-point is registered with a suitable indicator, which plays an important role in the titration process. A variety of indicators has been described in the literature [31,36], An example of an effective indicator used in two-phase titration is a mixture of anionic dyestuff, disulfine blue VN, and cationic dyestuf, dimidium bromide, the structures of which are shown in Fig. 11-32 (b,c). 

Like anionic surfactants, cationics can also be determined by formation of ion pairs with colored water-soluble anionic species, extractable into chloroform only in the presence of cationic surfactants. One of the most widely used methods is based on disulfine blue [40]. The absorbance of chloroform extract containing cationic surfactant - disulfine blue complex is measured at 628 nm against chloroform background. Picric acid and sodium p-(2-hydroxy-... 

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). 

Patent blue V Disulfine blue Acid blue 3 Patent blue violet Food blue 5 Trade name—Bleu Patente V Guerbet 3536-49-0/42051... 

Fairly drastic conditions are required to desorb cationic surfactants from solids. Extraction with methanolic HCl resulted in optimum recovery [44,45]. However, the extract has to be purified by extraction into chloroform in the presence of disulfine blue [44] or LAS [45]. Finally, cleavage of the ion pairs is done on ion exchangers. Hellmann used an AI2O3... 

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. 

Maiti and Saha [65] described a dye partition technique [66-68] utilising disulfine blue for the qualitative detection and, in some cases, the determination of amino end groups in the free radical polymerisation of PMMA. They found only 0.01-0.62 amino end groups per chain in PMMA made by amino-azo-bisbutyronitrile system, whereas in polymer made by the titanous chloride and acidic hydroxylamine systems they found 1.10-1.90 amino end groups per chain. 

Saha and co-workers [70] and Palit [66, 67] developed a dye-partition method for the determination of halogen atoms in copolymers of styrene, methylmethacrylate, methylacrylate, or vinyl acetate with a chlorine-bearing monomer such as allyl chloride and tetrachloroethylene. Copolymers were quaternised with pyridine, then precipitated with petroleum ether or alcohol, and fnrther purified by repeated precipitation from their benzene solutions with a mixture of alcohol and petroleum ether as the non-solvent. The precipitated polymers were then washed with petroleum ether and dried in air. The test for quaternary halide groups in polymers was carried out with a reagent consisting of disulfine blue dissolved in 0.01 M hydrochloric acid and the colour evaluated spectrophotometrically at 630 nm. Saha and co-workers [70] and Palit [66, 67] found that there may be some imcertainty in the quantitative aspects of this method. 

An elegant form of the two-phase titration method for the determination of an anionic surfactant is the following. Benzethonium chloride (Hyamin 1622, Rohm and Haas) is used as a cationic surfactant, while a mixture of diimidium bromide (cationic) and disulfin blue VN (anionic) is used as the indicator. The anionic surfactant forms a pink complex with the cationic diimidium bromide, which dissolves in the chloroform. Upon titration with Hyamin 1622, a stronger complex is formed with the anionic surfactant. Hyamin 1622 thus displaces the diimidium bromide and the organic phase is decolorized, while the aqueous phase turns red. Excess Hyamin 1622 forms a blue salt with the anionic disulfin blue VN, which then dissolves in the organic phase. 

Volumetric methods are the traditional methods employed in routine controL specifically two-phase titration for anionic and cationic surfactant determination, and are characteristically highly sensitive. They are based on the reaction between an anionic surfactant and cationic surfactant (one of which is a sample surfactant and the other a titrant surfactant) in a two-phase system (chloroform-water). The endpoint is detected by a transfer-phase indicator, the most common of which is a mixture of dimidium bromide and disulfine blue although methylene blue (Epton method), which is the first indicator chronologically, is also applied. Two commonly used titrants are sodium lauryl sulfate for cationic surfactants and benzethonium chloride, currently named Hyamine 1622, for anionic surfactants. 

A mixture of anionic surfactants (salts of fatty acids (currently named soaps), alkyl sulfates and alkyl sulfonates may be determined by three titrations. These three surfactants are titrated using dichlorofluorescein as indicator a dimidium bromide and disulfine blue mixture are used for titration of alkyl sulfates and alkyl sulfonates, while disulfine blue is used for alkyl sulfonates titration after acid hydrolysis (Cozzoli, 1993). 

Diethylamino)phenyl 2,4-disulfopheny[)methylene]-2,5-cyclohexadien-l-ylidene]-N-ethylethanaminium, 9CI. [4-[(X-[p- Diethylamino)phenyl -2,4-disulfobenzylidene]-2,5-cyclohexadien-l-ylidene]diethylammonium, SCI. Blue VRS. Disulfine blue VNS. C.I. Acid blue I. C.I. Food blue 3. Alphazurine 2G. Sulfan blue. Patent blue V. C.I. 42045 [116-95-0]... 

Determination of Cationic Surfactants with Disulfine Blue... 

According to Kunkel [67], the cationic surfactants are, by blowing out, concentrated in ethyl acetate and largely separated from interfering non-surfactant substances. Additions of an anionic surfactant and a neutral salt to the water sample ensure a complete transfer into the organic phase. After separation of the layers and evaporation of the solvent, the anionic surfactants are separated off by means of ion exchangers and the cationics are determined photometrically by a modified disulfine blue method. To avoid troublesome turbidity in this method, the dye complex formed is removed from the CHCI3 solution and redissolved in methanol. 

Another scheme calls for adjusting two surfactant aliquots to pH 1 and pH 11, respectively. The solutions are mixed with chloroform and treated with the mixture of two indicators used in two-phase titration (Chapter 16), dimidium bromide and disulfine blue. If only soap is present, the chloroform phase will be colorless at low pH and red at high pH other anionics will show the pink color in the chloroform phase at each pH. Quaternary amines will color the chloroform phase blue at either pH, while other amines will only yield the blue color at low pH nonionics show no color. Obviously, mixtures of surfactants will give confused results (27,30). 

Disulfine blue is the dye most often used for determination of cationic surfactants, esjre-cially in environmental matrices. The disulfine blue method is made suitable for the analy-... 

Procedure Determination of Cationic Surfactants by Reaction with Disulfine Blue (119) Reagents ... 

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