Matter methylene blue

The method developed by Epton [212,213] became the universally accepted method for the analysis of active matter of anionic and cationic surfactants. Epton s method, also known as the two-phase titration, is based on the titration of the anionic surfactant with cetylpyridinium bromide, a cationic surfactant, in the presence of methylene blue as indicator. A solution of the anionic surfactant is mixed with the indicator dissolved in dilute sulfuric acid, followed by further addition of chloroform, and then it is titrated with the cationic surfactant. Methylene blue forms a complex with the anionic salt that is soluble in chloroform, giving the layer a blue color. As the titration proceeds there is a slow transference of color to the water layer until the equivalence point. At the equivalence point colors of the chloroform and water layers are visually the same. On successive additions of titrant the chloroform layer lightens in shade and finally becomes colorless. 

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. 

The presence of chloride, nitrate, sulfide, organic sulfonates, cyanates, organic amines, and particulate matters may interfere in the test. The two major interferences, chloride and nitrate, however, may be removed in the acid backwash steps. Sulfide reacts with methylene blue to form a colorless complex. Interference from sulfide may be removed by treating the sample with a few drops of 30% H2Oz, whereupon sulfide converted into sulfate. 

Eerntlisen [36] showed later that certain dyestuffs containing sulphur (methylene blue and Lauth s violet) also belong to this class of colouring-matters. 

Cotton is also tested for ligneous matter by absorption of dyes (fuchsine, methylene blue, malachite gpreen) and for the viscosity of its solution in cuprammonium liquor. Gabillion gives the following figures for various cottons —... 

Modeling photocatalytic reaction processes requires careful consideration of reaction and adsoiption phenomena. In order to establish the importance of these matters, experiments can be developed using model pollutants such as methylene blue, phenol, 2-chlorophenol, 2,4-dichlorophenol, catechol (or 1,2 benzenediol), andpyrogallol (or 1,2,3 benzenetriol), each having quite different behaviours of adsorption and reaction. 

Sulfide is mainly produced in natural waters from the oxidation of organic matter, and it is highly toxic to most aquatic organisms. Extensive sample manipulation should be avoided in order to minimize loss of analyte by air oxidation or volatilization, and hence flow methodologies are advantageously used. Both methylene blue and nitroprusside methods are the most popular spectrophotometric procedures to measure the sulfide content in various water matrices. Isolation and preconcentration steps for matrix... 

A cytochrome reductase from liver microsomes was found by Stritt-matter and Velick to oxidize DPNH and to reduce a microsomal cytochrome, but not cytochrome c. This enzyme does not reduce methylene blue, but it does react with ferricyanide. 

Dissolve 0-1 to 0 4 g of methylene blue in 100 ml of water or extract pills with 5 per cent acetic acid, filter the acid extracts hot, cool and shake with carbon tetrachloride to remove traces of paraffin or fatty matter. Add 50 ml of 0-1N potassium dichromate, heat the mixture to 75° for five minutes, cool and filter through a tared No. 3 sintered-glass filter or a Gooch crucible. Wash with O IN dichromate, then with 0-02N dichromate and finally with a few ml of water, dry at 105°, cool and weigh. Each g of precipitate is equivalent to 0-8151 g of anhydrous methylene blue. 

L-Lysine is converted by an enzyme from a strain of Pseudomonas into y-aminovalerianic acid, NH3, and COg. The rate of incorporation of in dry matter is fairly important. These results point to the frequent occurrence of reactions such as (91) and many others similar and unknown. In the L-lysine oxidase experiments oxygen consumption cannot be affected by crystalline catalase. Methylene blue, triphenyltetrazolium chloride, and 2,6-dichlorophenolindolephenol cannot replace oxygen. 

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