Quantitative determination of polyethylene glycols in nonionic surfactants by high pressure liquid chromatography

Abstract

A method employing high pressure liquid chromatography has been developed for the quantitative determination of polyethylene glycols in ethoxylated fatty alcohols and alkylphenols. This technique overcomes many of the limitations encountered in previously-reported methods. The polyethylene glycols are separated from the ethoxylated product and other sample components using a 65/35 acetonitrile/water mobile phase and a Bondapak C18/Corasil reversephase column system. The response factor of the differential refractometer detector is determined using Carbowax standards of appropriate molecular weights. The molecular weight of the polyethylene glycols in each sample is approximated using thin layer chromatography prior to the high pressure liquid chromatography calibration and analysis. The precision of this method for the determination of polyethylene glycols is -+ 4% relative or better, and the recovery of added polyethylene glycols is quantitative. Application of this method to a wide variety of commercial ethoxylated fatty alcohols and alkylphenols is presented.

Behavior and fate of ethoxylated alkylphenol nonionic surfactant in barley plants

“…The cartridges were washed with 3-10 mL of water and the adsorbed materials were eluted with 3-10 mL of methanol. The 14C-labeled components were expected to be removed from the aqueous samples since nonionic surfactants with various EO contents were retained on reversed-phase columns (Turner et al, 1976;Henke, 1978) as were glycosides with relatively large aglycon moieties (Erni and Frei, 1977; Seitz and Wingard, 1978).…”

Analysis of Nonionic Surfactants with Polyoxyethylene Chains by High-Performance Liquid Chromatography

“…Being completely hydrophilic in their nature, polyoxyethylene glycols are eluted as a single peak with a constant retention time, irrespective of their molecular weights [87,94]. Their attraction to the mobiIe phase in this system is so strong that they do not interact with the stationary phase at all and their retention volume equals a column dead volume.…”

“…Detection in isocratic systems may also be performed with an RI detector, suitable for determining the homologue distribution of relatively simple mixtures (i.e., comprising up to 10 components) [64], as well as for determining total contents of polyoxyethylene glycols which, being more hydrophilic compared with ethoxylated alkylphenols, alcohols and acids, are eluted as a single peak at the beginning of the chromatogram [87,94]. The RI detector is also useful for determining the contents of dialkyl esters in ethoxylated fatty acids which are eluted as a single peak next to polyoxyethylene glycols and monoalkyl esters on reversed [94] and before them on normal phases 164,651.…”

Estimation of polyoxyethylene chain distribution of alcohol and alkylphenol ethoxylates

“…RI detection, cannot be used in gradient mode HPLC, which is necessary for separation of such complex polydisperse mixtures, and it has low sensitivity, which may be decisive in trace analysis. However, it is useful in determination of the total content of PEG in oxyethylation products under isocratic conditions with either CH3OH or CH3CN as an organic modifier [19,20].…”