Amine oxides dodecyl sulphate

Abbreviations BSA, bovine serum albumin Chi, chlorophyll DCPIP, 2, 6-dichlorophenol indophenol DMBQ, 2, 6-dimethyl-l, 4-benzoquinone DTT, dithiothreitol Fd, ferredoxin Hepes, N-2-hydroxyethyl-piperazine N -2-ethane sulphonate LDAO, lauryldimethyl amine oxide Mes, 4-morpholine ethane sulphonic acid MV, methyl viologen PAGE, polyacrylamide gel electrophoresis PRuK, phosphoribulokinase PS, photosystem Ru5P, ribulose 5-phosphate SDS, sodium dodecyl sulphate TMPD, N, N, N, N -tetramethyl paraphenylene diamine TRX. thioredoxin... 

Surfactants Ionic, anionic (e.g., sodium dodecyl sulphate, Cj2H250S03 Na ), cationic (e.g., cetyl trimethyl ammonium chloride, Ci,H33-N+(CH3)3C1-), zwitterionic [e.g., 3-dimethyldodecylamine propane sulphonate (betaine CJ2H25-N" (CH3)2-CH2-CH2-CH2-S03)], nonionic, alcohol ethoxylates C H2 +i-0-(CH2-CH2-0) -H, alkyl phenol ethoxylates C H2 +i-CgH4-0-(CH2-CH2-0) -H, amine oxides (e.g., decyl dimethyl amine oxide, C10H21-N ( 113)2 0), and amine ethoxylates. 

As in previous chapters, this chapter deals with the analysis of cationics and amphoterics either alone, as raw materials or as fractions isolated by ion exchange or otherwise, or in formulated products. Fractions isolated by ion exchange are likely to contain other materials, analogously with anionics. Amines, ethoxylated amines and amine oxides are included in this chapter because they are bases and capable of a cationic function. They are retained as cations by ion-exchange columns and do not appear in the nonionic fraction of separated mixtures, they can be titrated with acids and, in acid solution, with sodium dodecyl sulphate, provided the ethylene oxide chains of ethoxylates are not too long. 

Ethoxylated amines with short ethylene oxide chains can be titrated with sodium dodecyl sulphate and NaTPB in acid solution, but the titrations become increasingly unsatisfactory as the chain length increases. The same is no doubt true of ethoxylated diamines. Commercial ethoxylated amines have typically 12-60 EO units, and the diamines have up to 25. 

The determination of amine oxides is straightforward they can be titrated in acid solution with sodium dodecyl sulphate or NaTPB, either poten-tiometrically or in a two-phase system, for which purposes the solution must be at least 0.1 M in hydrogen ion, and they can be titrated with acid. However, for quality-control purposes it is necessary to determine the free tertiary amine content. This can be done by potentiometric titration, either in a solvent which permits discrimination on the basis of base strength, or before and after removal of the amine oxide. Methods are described for both of these. 

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