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The esterification of fatty alcohol ethoxylates (FAEs) with phthalic anhydride in 1,4-dioxane was studied. At 110 degrees C and in the presence of urea, which increased the reaction rate, esterification was completed in 60 min. The reaction yield did not decrease when the sample contained up to 50% water. For the non-ethoxylated alcohols, the UV-vis response factors of the derivatives were not significantly different from each other (f=1 for C12E0 as reference). The response factors decreased when the number of ethylene oxide units, m, increased, reaching constant values of ca. 0.40 and 0.65 for the n=8 and 18 series, respectively, when m>or=3. Using a C8 column and gradient elution with acetonitrile/water plus 0.1% acetic acid, FAEs in industrial mixtures and cleaning products were characterized. At column temperatures of 25 and 35 degrees C, homologous series with even values of n from 8 up to 20, were resolved up to m=14 and 18, respectively, and at 25 degrees C, series with consecutive even and odd values of n were resolved up to m=7. Within the series, superior resolution of the ethoxymers with large values of m was achieved; however, the elution order was reversed for the m=1 and 0 ethoxymers, which produced overlapping of a few peaks within the series. A simple procedure for the accurate prediction of the concentrations of all the ethoxymers in industrial samples was described. After preconcentration with C18 solid-phase extraction cartridges, FAEs were also characterized and quantified in environmental samples (river and sea water). The LODs were ca. 2 microM (S/N=3) in the injected solutions.

A column selection valve and a 6-port 2-position injection valve were combined to implement bi-dimensional LC in a system driven by a single pump. The system was applied to the separation of linear fatty alcohol ethoxylates with 12-18 carbon atoms in the hydrocarbon moiety, previous derivatization with diphenic anhydride. Separation on the first separation dimension (C(1)) was carried out with a propyl-diol column and an acetonitrile/aqueous ammonium acetate gradient. Fatty alcohol ethoxylate hydrocarbon series (oligomers with the same number of carbon atoms in the alkyl chain but differing in the number of ethylene oxide units) were resolved without distinguishing the oligomers within the series. Selected segments of the eluate of C(1) were transferred to the second column (C(2)), where the successive oligomers within the isolated series were resolved by using either an octyl-silica or a pentafluoro-phenyl-propyl column and an acetonitrile/water gradient. Flow stopping at C(1) during system re-conditioning and elution along the second dimension did not produce any noticeable band broadening. Overlapping of the non-ethoxylated and mono-ethoxylated oligomers with other oligomers within the series was avoided by eluting the pentafluoro-phenyl-propyl column at low temperatures (3 degrees C).

Methods for the rapid characterization of industrial alkylpolyphosphonates (APPs) by infusion MS and CZE with indirect photometric (IPD) and MS detection are described. Technical-grade APPs, including alkylaminepolyphosphonates with 3-5 phosphonate groups and different hydrocarbon skeletons, hydroxyethyl-amino-bis(methylenephosphonic acid), hydroxyethylidene-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid, were examined. A 10 mM solution of adenosine triphosphate disodium salt at pH 2.2 was used as BGE. The nominal compounds of the industrial APPs and their impurities were well resolved in less than 15 min. The peaks were identified by using extracted ion electropherograms, which were obtained at the m/z values indicated by the peaks of the infusion spectra. Low concentrations of esters, anhydrides, and APPs having different hydrocarbon skeletons compared to nominal compounds, and lacking phosphonate and methylene-phosphonate groups with respect to them, were found. Also, hydroxyethyl-aminobis(methylenephosphonic acid) contained an intramolecular ester at a concentration close to that of the nominal compound. Application of CZE-IPD and CZE-MS to the quality control of industrial APPs, and of CZE-MS to the identification and characterization of APPs in cleaning products, was demonstrated.