Alkylphenol ethoxylates analysis

FD-MS is also an effective analytical method for direct analysis of many rubber and plastic additives. Lattimer and Welch [113,114] showed that FD-MS gives excellent molecular ion spectra for a variety of polymer additives, including rubber accelerators (dithiocar-bamates, guanidines, benzothiazyl, and thiuram derivatives), antioxidants (hindered phenols, aromatic amines), p-phcnylenediamine-based antiozonants, processing oils and phthalate plasticisers. Alkylphenol ethoxylate surfactants have been characterised by FD-MS [115]. Jack-son et al. [116] analysed some plastic additives (hindered phenol AOs and benzotriazole UVA) by FD-MS. Reaction products of a p-phenylenediaminc antiozonant and d.v-9-lricoscnc (a model olefin) were assessed by FD-MS [117],... 

It is important that any method for surfactant analysis maintains the same oligomer distribution in the extracted samples. LLE and SPE are generally combined with chromatographic methods for separation and resolution of non-ionic surfactants into their ethoxamers. An alternative is the use of SPME-HPLC, recently reported by Chen and Pawliszyn [141]. Alkylphenol ethoxylate surfactants such as Triton X-100 and various Rexol grades in water were determined by means of SPME-NPLC-UV (at 220 nm) [142]. Detection limits for individual alkylphenol ethoxamers were at low ppb level. 

Similar results were shown for the analysis of alkylphenol ethoxylates, which could only be separated on Spherisorb silica using acetonitrile and water (Rissler 1994). Since water-acetonitrile gradients give better resolution over water-methanol gradients for the analysis of PEG S, it was proposed that methanol shields residual... 

Gas chromatography (GC) has developed into the most powerful and versatile analytical separation method for organic compounds nowadays. A large number of applications for the analysis of surfactants have emerged since the early 1960s when the first GC papers on separation of non-ionics were published. The only major drawback for application of GC to surfactants is their lack of volatility. This can be easily overcome by chemical modification (derivatisation), examples of which will be discussed extensively in the following paragraphs. This chapter focuses on surfactant types, and in addition discusses some structural aspects of alkylphenol ethoxylates (APEOs) that are important for, as well as illustrative of, aspects of separation and identification that are linked to the complexity of the mixtures of surfactants that are involved. 

The trend of discovering the analytical field of environmental analysis of surfactants by LC-MS is described in detail in Chapters 2.6-2.13 and also reflected by the method collection in Chapter 3.1 (Table 3.1.1), which gives an overview on analytical determinations of surfactants in aqueous matrices. Most methods have focused on high volume surfactants and their metabolites, such as the alkylphenol ethoxylates (APEO, Chapter 2.6), linear alkylbenzene sulfonates (LAS, Chapter 2.10) and alcohol ethoxylates (AE, Chapter 2.9). Surfactants with lower consumption rates such as the cationics (Chapter 2.12) and esterquats (Chapter 2.13) or the fluorinated surfactants perfluoro alkane sulfonates (PFAS) and perfluoro alkane carboxylates (PFAC) used in fire fighting foams (Chapter 2.11) are also covered in this book, but have received less attention. 

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]. 

Analysis of alkylphenol ethoxylates and degradation products in drinking water... 

Important classes of nonionic surfactants are aliphatic poly-ethoxylate alcohols (AEO), and octyl or nonyl phenol polyethoxylates (OPEO and NPEO). The alkylphenol ethoxylates (APEO) attracted special attention due to their supposedly endocrine disrupting properties (Ch. 8.3). LC-MS analysis may also involve nonylphenolethoxycarboxylates (NPEC), biodegradation products of NPEO, and halogenated analogues, generated in chlorine disinfection treatments in drinking water production plants. 

Ferguson, P. L., Iden, C. R., and Brownawell, B., Analysis of alkylphenol ethoxylate metabolites in the aquatic environment using liquid chromatography-electrospray mass spectrometry. Ana/. Chem., 72, 4322-4330, 2000. 

KubeckE, Naylor CG (1990) Trace analysis of alkylphenol ethoxylates. J Am Oil Chem Soc 67 400-405... 

Thiele B, Gunther K, Schwuger MJ (1997) Alkylphenol ethoxylates trace analysis and environmental behavior. Chem Rev 97 3247... 

Simultaneously with the use of PBI for the analysis of pesticides and agrochemicals, both dispersed in large quantities in the environment [109], this interface type was also appHed to perform the determination of a broad spectrum of pollutants generated by degradation processes, mobilized from waste disposals and contained in the leachates [110] and finally found in the aquatic environment The analysis of 500 L samples of drinking water made the pollution of these waters with alkylphenol ethoxylates (APEOs) and alkylphenol carboxylates (APECs) obvious [111]. As polar constituents of wastewater samples non-ionic surfactants of NPEO type and their acidic metaboHtes, plasticizers, and plastic additives could be confirmed by the appHcation of PBI-LC-MS [112]. 

The analyses of environmental samples confirmed the ubiquitious presence of surfactants in surface and sea water as a result of the surfactants discharged with STP effluents. Analysis of River Elbe (Germany) water samples by GC-MS and APCl-LC-MS and MS/MS confirmed qualitatively the presence of nonpolar and polar organic pollutants of AEO, NPEO, CDEA and aromatic sulfonic acid type, respectively [226], After Cjg and/or SAX SPE anionic and non-ionic surfactants were qualitatively and quantitatively analysed in surface water samples by APCI-LC-MS in the negative or positive mode, respectively. Alkylphenol ethoxylates (APEOs) could be confirmed in river water at levels of 5.6 pg L [331]. 

A large number of pubUcations have resulted from research on environmental appHcations of GC-MS. The compounds most commonly analyzed include alkanes, PAHs, pesticides, volatile organic compounds (VOCs) including off-flavor and water disinfection by-products (DBPs), PCBs, polychlorinated dibenzo-p-dioxins, and furans (PCDDs/Fs), as well as other ED chemicals such as phthalates and short ethoxy alkylphenol ethoxylate. GC-MS is also the technique of choice for the analysis of emerging contaminants, such as polybrominated diphenyl ethers (PBDEs) or polychlorinated alkanes, as well as for the analysis of some pharmaceuticals and organo-metallic compounds. 

ASTM Test Method D 4252-89 Standard Test Methods for Chemical Analysis of Alcohol Ethoxylates and Alkylphenol Ethoxylates. American Society for Testing and Materials, Philadelphia, USA. 

Nonionics. The determination of nonionic surfactants using a silanised silica gel GF254 layer with aqueous 80% methanol and the use of a scanning densitometer at 525 nm for detection is described in [43]. Analysis of alkylphenol ethoxylates using a Kieselgel F60 layer with chloroform methanol as mobile phase and IR detection is described in [44]. 

D 4252-89 Chemical Analysis of Alcohol Ethoxylates and Alkylphenol Ethoxylates... 

American Society for Testing and Materials, Chemical analysis of alcohol ethoxylates and alkylphenol ethoxylates, D4252-89 (1995). West Conshohocken, PA 19428. 

TABLE 9 TLC Analysis of Alkylphenol Ethoxylate Nonionic Surfactants... 

TABLE 3 Analysis of Alkylphenol Ethoxylate Surfactants by Supercritical Fluid Chromatography... 

The complete analysis of alcohol sulfates is described in the Standard Methods of the International Organization of Standards (ISO) [200] and of the American Society for Testing and Materials (ASTM) [201]. These methods describe the analysis of inorganic sulfate content, chloride content, unsulfated matter, and water as well as other analytical values. Other ISO standards describe the analysis of sodium secondary alkyl sulfates [202], determination of pH [203], determination of water content [204,205], chlorides [206], total active matter in sul fated ethoxylated alcohols and alkylphenols [207], mean relative molecular mass in sulfated ethoxylated alcohols and alkylphenols [208], sulfate content... 

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. 

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