Environmental issues ethoxylated surfactants

The quantitative environmental analysis of surfactants, such as alcohol ethoxylates, alkylphenol ethoxylates (APEOs) and linear alkylbenzene sulfonates (LASs), is complicated by the presence of a multitude of isomers and oligomers in the source mixtures (see Chapter 2). This issue bears many similarities to the quantitation problems that have occurred with halogenated aromatic compound mixtures, e.g. polychlorinated biphenyls (PCBs) [1]. 

Among different nonionic surfactant classes, alkyl-phenol ethoxylates (APEOs) comprise the class meriting special attention with respect to environmental issues. The analysis of underivatized alkylphenolic compounds by GC-MS is restricted to the most volatile degradation products, such as alkylphenols and APEOs with less then 4-ethoxy groups. To overcome the problem of volatility, different offline and online derivatization protocols have been developed. Two complementary MS techniques, one using El and another using the less commonly used positive (P)CI, have been evaluated for the analysis of APEOs, their acidic (APECs) and neutral metabolites (APs), and halogenated derivatives. 

Snrfactants are employed to stabihze the emulsion polymer particles anionic, cationic, and steric stabihzers are all used for the production of latexes, depending on whether one wants a negative, positive, or neutral potential surface on the formed pol5uner particle. The specific anionic options available for use are alkyl sulfates, alkyl sulfosuccinates, and alkylarene sulfonates and phosphates. Standard nonionic surfactants include alkyl or aryl polyoxyethylenes. In recent years, alkyl phenol ethoxylates have fallen into disfavor because of their reported problems with bioaccumulation in aquatic hfe. This still somewhat controversial, environmentally-driven issue has necessitated the use of alternative surfactants which have a lower impact on the environment. Typically, the aryl ring is eliminated to solve this problem. 

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