Class Of Cationic Surfactants Research Articles

Simultaneous determination of seven quaternary ammonium compounds in frozen food by ultra performance liquid chromatography-tandem mass spectrometry combined with modified QuEChERS method

Quaternary ammonium compounds (QACs) are a class of cationic surfactants that can be used as the main active ingredient of disinfectants. The increased use of QACs is concerning as exposure from inhalation or ingestion to these compounds that has been associated with adverse effects on the reproductive and respiratory systems. Humans are exposed to QACs primarily by food consumption and inhalation of air. QAC residues pose significant threats to public health. Given the importance of assessing potential residue levels for QACs in food, therefore, a method was developed for the simultaneous detection of six common QACs and one emerging QAC (Ephemora) in frozen food by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with the modified QuEChERS method. The main factors governing the response, recovery, and sensitivity of the method, including extraction solvents, types and dosages of adsorbents, apparatus conditions, and mobile phases, were optimized in the course of sample pretreatment and instrument analysis. QAC residues in frozen food were extracted using 20 mL methanol-water (90∶10, containing 0.5% formic acid) for 20 min by the vortex shock method. The mixture was ultrasonicated for 10 min and centrifuged at 10000 r/min for 10 min. A 1-mL aliquot of the supernatant was transferred to a new tube and purified using 100 mg of PSA adsorbents. After mixing and centrifugation at 10000 r/min for 5 min, the purified solution was analyzed. Target analytes were separated on an ACQUITY UPLC BEH C8 chromatographic column (50 mm×2.1 mm, 1.7 μm) at a column temperature of 40 ℃ and a flow rate of 0.3 mL/min. The injection volume was 1 μL. Gradient elution was performed using methanol and 5 mmol/L ammonium acetate solution as the mobile phases. Multiple reaction monitoring (MRM) was conducted in the positive electrospray ionization (ESI+) mode. The matrix-matched external standard method was used to quantify seven QACs. The optimized chromatography-based method completely separated the seven analytes. Good linear relationships were obtained for the seven QACs in the range of 0.1-100.0 ng/mL. The correlation coefficient (r2) ranged from 0.9971 to 0.9983. The limits of detection and limits of quantification ranged from 0.5 to 1.0 μg/kg and 1.5 to 3.0 μg/kg, respectively. Accuracy and precision were determined by spiking salmon and chicken samples with 3.0, 10.0, and 100.0 μg/kg of analytes, in compliance with the current legislation, with six replicates per determination. The average recoveries of the seven QACs ranged from 65.4% to 101%. The relative standard deviations (RSDs) were between 0.64% and 16.8%. Matrix effects of the analytes were between -27.5% and 33.4% in salmon and chicken samples after purifying using PSA. The developed method was applied to the determination of seven QACs in rural samples. QACs were detected in only one sample; the level did not exceed European Food Safety Authority specified residue limit standards. The detection method has high sensitivity, good selectivity and stability, and the results are accurate and reliable. It is suitable for the simultaneous rapid determination of seven QAC residues in frozen food. The results provide valuable information for future risk assessment studies targeting this class of compounds.

Synthesis of Rice Bran Fatty Acids (RBFAs) Based Cationic Surfactants and Evaluation of Their Performance Properties in Combination with Nonionic Surfactant

Abstract Cationic surfactants are mainly used for fabric softening in laundry applications. Esterquats are one class of cationic surfactants and are superseding other existing cationic surfactants on account of their excellent biodegradability. However, indigenous and cost-effective production of esterquats poses new challenges for the researchers. The availability of rice bran fatty acids and its price structure in Indian scenario makes this fatty feedstock quite lucrative for cost-effective synthesis of cationic surfactants. In the present study, esterquats based on rice bran fatty acids (RBFAs) were synthesized by using different alkanolamines i. e. diethanolamine (DEA) and triethanolamine (TEA) and dimethyl sulphate (DMS) for obtaining cationic surfactants which was used as active softener ingredient. For this purpose, esterquats have been synthesized by esterification of RBFAs and alkanolamines to recover diesters followed by the subsequent quaternization of diesters by DMS. It was found that the optimum reaction conditions for esterification of RBFAs and DEA was 140 °C and 3 h of duration. However, for RBFAs and TEA, it was found to be 140 °C and 4 h of duration. The chemical structures of diesters and esterquats were confirmed by FT-IR and NMR spectra. Studies of surface active and performance properties of these surfactants showed that esterquats based on TEA had better surface active and performance properties as compared to DEA based esterquats. The synthesized cationic surfactants when mixed with nonionic surfactant showed better performance properties as compared to the nonionic surfactant alone.

Quaternary Ammonium Compounds in Urban Estuarine Sediment Environments - A Class of Contaminants in Need of Increased Attention?

The distributions of wastewater-derived quaternary ammonium compounds (QACs) were determined in surficial sediments (n = 47) collected from the urbanized lower Hudson River basin. The most abundant class of QACs were dialkyldimethylammonium compounds (DADMACs, with C8 to C18 carbon chain lengths; median ΣDADMAC = 26 μg/g), followed by benzylalkyldimethylammonium compounds (BAC, C12-C18; 1.5 μg/g), and alkyltrimethylammonium compounds (ATMAC, primarily C16 and C18; 0.52 μg/g). The concentrations of total QACs are higher than those of other conventional organic contaminants determined on the same samples (e.g., median ΣPAH level of 2.1 μg/g). Comparatively high concentrations, correlations with sewage derived contaminants, and the relatively constant compositions of QACs observed over large areas suggest that many sediment-sorbed QACs can be relatively persistent in receiving waters. Unusually large concentration-dependent sorption is considered as a mechanism that likely affects persistence of these intrinsically biodegradable chemicals under field conditions. There has been comparatively little field-based research on these classes of cationic surfactants; given the levels of QACs observed here, it is suggested that further investigation is warranted.

Esters of ω‐Bromo Alcohols and Their Corresponding Quarternary Ammonium Salts

A new class of cationic surfactants is presented. One (4c) shows a lyotropic mesophase.

Decarboxylation of 6-nitrobenzisoxazole-3-carboxylate as kinetic probe for piperazinium-based cationic micelles

A new class of cationic surfactants containing the heterocyclic piperazinium ring in their covalent structure was prepared; cetyldialkylpiperazinium halides, CRPX, with alkyl=Me (CMPX), Et (CEPX), n-Pr (CPPX), and with halide=Br and Cl. They were characterized by measures of critical micellar concentration, cmc, and ionization degree, α, and also by use of the decarboxylation of 6-nitrobenzisoxazole-3-carboxylate as a kinetic probe to investigate the properties of the microinterface they provide in aqueous solutions. The pseudophase kinetic treatment fails to fit the data at high [surfactant], which show anomalies with abrupt increase in k obs, especially for CEPX and CPPX. Data can be fitted up to [surfactant] ca. 0.1 M, and 0.2 M in some cases. Compared with cetyltrialkylammonium halides, values of k′ M indicate a water-richer microenvironment and less important interface property changes with increasing head group bulk. The reaction could be studied both in the presence and in the absence of NaOH; comparison shows that NaOH affects only the shape of the kinetic profile at low [surfactant], without affecting the microenvironment provided by mature micelles.

New Cationic Surfactants with Sulfonium Headgroups

The synthesis of a new class of cationic surfactants with sulfonium headgroups is presented. The use of common and easily accessible reactants allows a broad variation of the molecular surfactant structures, i.e., the synthesis of not only linear homologues but also of bola- or star-shaped surfactants. Surface tension measurements were used to determine the critical micelle concentration (cmc) and the surface excess concentration Γ∞. The lyotropic phase behavior was investigated by polarized light optical microscopy. The influence of the hydrophobic chain length, the molecular structure of the headgroup, and the counterion on the surfactant properties is discussed.

Effect of the Carboxylic Group on Thermodynamic Properties of Aqueous Micellar Solutions of Amphiphilic Betaine Ester Derivatives

The results of thermodynamic study at 313 K in aqueous solutions of some amphiphilic betaine chloride ester derivatives (C n-BEC, n = 10, 12, 14), showing biological activity, are here reported for the first time. Dilution enthalpies were measured by means of a flow type microcalorimeter, the density (at 298 and 313 K) was measured by means of a vibrating tube densimeter, and the osmotic coefficients by means of a vapor pressure osmometer. Apparent and partial molar quantities were obtained from the experimental data and expressed as a function of molalities, assuming the infinite dilution as standard state. On the basis of pseudo-phase separation model, the values of enthalpies and volumes of micellization were graphically evaluated. Using the calculated enthalpies of micellization at 313 K and previously reported values for 298 K, the heat capacities of micellization were also obtained. The general thermodynamic trend as a function of chain length is comparable with that of other homologous series of cationic surfactants, in spite of the presence of the carboxyl group. For this class of surfactants, too, the additivity rule seems to hold: for all the properties studied, the -CH 2- group contributions are comparable with those reported in the literature for other classes of cationic surfactants, despite the presence of the carboxylic group between the charged head and the hydrophobic tail. In micellar solutions, the -COO- group contribution to volume is 22.4 cm 3 mol -1 instead of 16.3 cm 3 mol -1 for each -CH 2-. The comparison of the trends of thermodynamic quantities of C 10-BEC with those of dodecyltrimethylammonium chloride (DTAC) supports the hypothesis that two methylene groups of DTAC and -CH 2-COO- group of betaine ester derivatives are not incorporated into the micelle core.

A new class of acid corrosion inhibitors: 2-Hydroxy-3-(2-undecyl, pentadecyl or heptadecyl amido-ethylamino) propane-1-tri-ethyl ammonium hydroxides

The inhibition of the corrosion of low carbon steel in 0.5M HCl by three compounds of a new class of cationic surfactants was studied, using the gasometric method, in the temperature range 19–60°C. More than 98% inhibition was achieved with an inhibitor concentration as low as 10 −4M. Inhibition by the three surfactants increased with the increase of additive concentration. It was not greatly affected by temperature. The apparent activation energy of the corrosion process in the absence and presence of the cationic surfactants was computed. Electrocapillary curves at a dropping mercury electrode were constructed for various concentrations of the different additives. These revealed that the three compounds are strongly adsorbed both on the anodic and cathodic sides of the electrocapillary curve maximum. † Faculty of Pharmacy, Pharmaceutical Chemistry Department, University of Alexandria. ‡ Faculty of Engineering, Chemical Engineering Department, University of Alexandria.

A new class of acid corrosion inhibitors: 2-hydroxy-3-(2-undecyl, pentadecyl or heptadecyl amido-ethylamino) propane-1-tri-ethyl ammonium hydroxides

The inhibition of the corrosion of low carbon steel in 0.5M HCl by three compounds of a new class of cationic surfactants was studied, using the gasometric method, in the temperature range 19–60°C. More than 98% inhibition was achieved with an inhibitor concentration as low as 10 −4M. Inhibition by the three surfactants increased with the increase of additive concentration. It was not greatly affected by temperature. The apparent activation energy of the corrosion process in the absence and presence of the cationic surfactants was computed. Electrocapillary curves at a dropping mercury electrode were constructed for various concentrations of the different additives. These revealed that the three compounds are strongly adsorbed both on the anodic and cathodic sides of the electrocapillary curve maximum.