Separation and Quantitation of Anionic, Cationic, and Nonionic Surfactants by TLC

Ionic Liquid in Thin-Layer Chromatography of Anionic Surfactants: Selective Separation of Sodium Deoxycholate and Identification in Commercial Products

The coupling of a silica static flat phase impregnated with an ionic liquid (1-methylimidazolium chloride) as stationary phase with 2-methyltetrahydrofuran an alternative green solvent of tetrahydrofuran as mobile phase has been very successful for a selective separation of sodium deoxycholate from other commonly used anionic surfactants. The proposed thin-layer chromatographic system is capable to analytically discriminate among the anionic surfactants in relation to their migration behaviour on an ionic liquid loaded silica layer. The surface structure and chemical composition of silica gel G modified by impregnation were examined with the aid of scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometry (EDX) respectively. Effects of concentration level of 1-methylimidazolium chloride as impregnant and its substitution by other ionic liquids (1,2,3-trimethylimidazolium methyl sulphate, 1-ethyl-3-methylimidazolium tetrafluoroborate) were also studied to decide the optimum experimental conditions for better separation possibilities. Chromatographic parameters such as ΔRF, the separation factor (α) and the resolution (RS) for the separation and limit of detection were calculated. The developed method has been usefully applied for the identification of sodium deoxycholate and sodium lauryl sulphate in formulated and commercially available products (Colgate toothpaste and Head & Shoulder Shampoo).

Ultrasonic Extraction and TLC Determination of Surfactants in Laundry Wastewaters

Standard method of surfactant determination is UV/VIS determination and a long time — consuming standard flask extraction with chloroform, in which very large quantities of harmful organic solvent are employed. In this work, ultrasonic solvent extraction of anionic, cationic and non-ionic surfactants was compared with the traditional shake-flask extraction method and both methods were applied on laundry wastewater samples. Separation, identification and quantification of surfactants were done by thin layer chromatography and video densitometry. Ultrasonic extraction procedure was optimized with regard to the amount of solvent and duration of extraction. This extraction method proved to be much better because it was faster and more efficient. Due to the application of much less organic solvent, it is both economically and ecologically favorable.

Analysis of Surfactants by Thin-Layer Chromatography: A Review

Thin-layer chromatographic analysis of surfactants is presented in this review. Various chromatographic systems useful for the identification, separation and quantification of surfactants are reported. New approaches in thin-layer chromatography enable analysts to separate and determine surfactants in complex mixtures (in various environmental samples). Thin-layer chromatographic methods are mainly used for the separation of surfactants either in the separation of different classes or separation of different groups within the same class.

Development of a fritless packed column for capillary electrochromatography-mass spectrometry

A novel procedure was developed for the fabrication of a fritless packed column for the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS). The process involved the formation of internal tapers on two separate columns. Once the internal tapers are formed and the columns are packed, the untapered ends of each column were joined together by a commercially available connector. Several advantages of the fritless columns are described. First, the design used here eventually eliminates the need for any frits thus reducing the possibility of bubble formation seen with fritted packed columns. In addition, this is the first report in which the internal tapers are formed at both the inlet and outlet column ends making the fritless CEC-MS column more robust compared to only one report with externally tapered counterparts. Second, a comparison of internally tapered single frit packed CEC-MS (previously developed in our laboratory) column versus fritless CEC-MS column reported here shows that the latter provides better efficiency, suggesting no dead volume with equally good sensitivity and chiral resolution of (±)-aminoglutethimide. The fritless column procedure is universal and was used to prepare a series of columns with a variety of commercially available packing material (mixed mode strong cation exchange, SCX; mixed mode strong anion exchange, SAX; C-18) for the separation and MS detection of short chain non-chromophoric polar amines, long chain nonchromophic anionic surfactant as well as oligomers of non-chromophoric non-ionic surfactants, respectively. The fritless columns showed good intra-day repeatability and inter-day reproducibility of retention times, chiral and achiral resolutions and peak areas. Very satisfactory column-to-column and operator-to-operator reproducibility was demonstrated.

Determination of cationic surfactants by capillary zone electrophoresis and micellar electrokinetic chromatography with deoxycholate micelles in the presence of large organic solvent concentrations

Mixtures of the cationic surfactants benzalkonium chloride (BKC) and cetylpyridinium chloride (CPC) were quickly resolved and reproducibly and reliably determined by using background electrolytes (BGEs) containing 80 mM borate, pH 8.5, bile salts and large concentrations of an organic solvent. When the bile salt is present, the separation mechanism changes from capillary zone electrophoresis (CZE) to a mixed micellar electrokinetic chromatography (MEKC)-CZE, with predominant MEKC interactions, which lead to an excellent resolution of all the solutes, including the C12-C18 homologues of BKC and CPC. A BGE containing 50 mM sodium deoxycholate and 30% ethanol for an extreme resolution, or 20% tetrahydrofuran for an adequate resolution within a much shorter analysis time, is recommended. The procedure was applied to the determination of the surfactants in industrial and household formulations, with excellent resolution between the homologues, detection limits of a few microg ml(-1) and reproducibilities below 2%.

A mild, rapid, and efficient method of lipid extraction for use in determining vitamin E/lipid ratios

A new, general method for lipid extraction and measurement of vitamin E/total lipid ratios in tissue and cell samples has been developed. The new extraction procedure uses a combination of sodium dodecylsulfate, ethanol and n-heptane, and is mild, clean, convenient, efficient and rapid (less than or equal to 5 min). The efficiency of the new method has been confirmed for human plasma, red blood cells and rat liver homogenate by the comparison of the yields of vitamin E, O-acyl lipid and cholesterol with the yields obtained following conventional extraction procedures. Extraction efficiency also has been confirmed for multilamellar vesicles composed of known quantities of vitamin E, egg lecithin and cholesterol.