Ribbon-shaped supramolecular solvents: Synthesis, characterization and potential for making greener the microextraction of water organic pollutants.

Liquid-liquid microextraction (LLME) techniques have experienced a tremendous growth over the last years but still face major challenges related to the use of more efficient and environmentally friendly solvents. Supramolecular solvents (SUPRASs) have proved outstanding efficiency in LLME, but many of the experimental conditions required for SUPRAS formation and/or application cannot be considered green or experimentally convenient. This paper was intended to make greener both SUPRAS formation and their application to the LLME of low-concentration organic pollutants in environmental waters.

Methanetriyl-pi hydrogen bonding in nonpolar domains of supramolecular nanostructures: An efficient mechanism for extraction of carcinogenic polycyclic aromatic hydrocarbons from soils.

Methanetriyl-pi hydrogen bonding (CH-π HB) in nonpolar domains of supramolecular nanostructures is proposed here as a new mechanism to increase the extraction efficiency of aromatic compounds. The approach is illustrated by the extraction of priority carcinogenic polycyclic aromatic hydrocarbons (CPAHs) in soils using supramolecular nanostructures of carboxylic acids with nonpolar domains consisting of hydrocarbon chains (C6-C10) dispersed in tetrahydrofuran (THF). The high concentration of CH-groups available in the supramolecular nanostructures (38.

Quick and Sensitive Enantioselective Determination of Permethrin in Fruits and Vegetables by Combining Supramolecular Solvents and Chiral Liquid Chromatography-Tandem Mass Spectrometry.

Permethrin (PM) is one of the chiral insecticides most widely used around the world. The significant differential toxicity of its four enantiomers and its important adverse effects on human health highlights the need for determination of PM enantiomers. The aim of this work was to develop the first enantioselective method for quantification of PM in fruits and vegetables.

The use of a restricted access volatile supramolecular solvent for the LC/MS-MS assay of bisphenol A in urine with a significant reduction of phospholipid-based matrix effects.

Restricted access-volatile supramolecular solvents (RAM-VOL-SUPRAS) are here proposed as a new strategy for the quick removal of protein and phospholipids and efficient analyte extraction in LC-MS bioanalysis. Quantification of bisphenol A in urine was selected to prove the suitability of this approach for the intended purpose. RAM-VOL-SUPRAS were spontaneously synthesized in urine by addition of hexanol (83 μL) dissolved in THF (150 μL).

Enantioselective analysis of non-steroidal anti-inflammatory drugs in freshwater fish based on microextraction with a supramolecular liquid and chiral liquid chromatography-tandem mass spectrometry.

Toxicity of pharmaceuticals to aquatic biota is still largely unknown, and no research on the stereoselective toxicity of chiral drugs to these organisms has been undertaken to date. Because of the lack of analytical methods available for this purpose, this manuscript deals, for the first time, with the enantioselective analysis of the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen, naproxen and ketoprofen in freshwater fish. The method was based on the microextraction of NSAIDs from fish muscle with a supramolecular liquid made up of inverted hexagonal aggregates of decanoic acid, their enantiomeric separation by liquid chromatography onto a (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid stationary phase and quantification by tandem mass spectrometry.

Determination of supplemental feeding needs for astaxanthin and canthaxanthin in salmonids by supramolecular solvent-based microextraction and liquid chromatography-UV/VIS spectroscopy.

Development of simple and rapid analytical methods for predicting supplemental feeding requirements in aquaculture is a need to reduce production costs. In this article, a supramolecular solvent (SUPRAS) made up of decanoic acid (DeA) assemblies was proposed to simplify sample treatment in the total and individual determination of carotenoids (red-pink pigments) in farmed salmonids. The analytes were quantitatively extracted in a single step that spends a few minutes using a small volume of SUPRAS (i.

Highly efficient microextraction of chlorophenoxy acid herbicides in natural waters using a decanoic acid-based nanostructured solvent prior to their quantitation by liquid chromatography-mass spectrometry.

Solvents used in microextraction require high solubilising capability to efficiently extract the target compounds. In this article, nanostructured solvents made up of alkyl carboxylic acids (ACAs) aggregate are proposed for the efficient microextraction of acidic pesticides from natural waters. The target compounds were chlorophenoxy acid herbicides (CPAHs) widely used in agriculture, forestry and gardening (viz.

Supramolecular solvents in the extraction of organic compounds. A review.

The increasing pressure to decrease organic solvent usage in laboratories is fostering the search for alternative solvents. The liquid-liquid phase separation of surfactants, induced by environmental conditions, viz. temperature, electrolytes, pH, etc.

Multiresidue analysis of sulfonamides in meat by supramolecular solvent microextraction, liquid chromatography and fluorescence detection and method validation according to the 2002/657/EC decision.

A multiresidue method was described for determining eight sulfonamides, SAs (sulfadiazine, sulfamerazine, sulfamethoxypyridazine, sulfachloropyridazine, sulfadoxine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline) in animal muscle tissues (pork, chicken, turkey, lamb and beef) at concentrations below the maximum residue limit (100 μg kg(-1)) set by the European Commission. The method was based on the microextraction of SAs in 300-mg muscle samples with 1 mL of a supramolecular solvent made up of reverse micelles of decanoic acid (DeA) and posterior determination of SAs in the extract by LC/fluorescence detection, after in situ derivatization with fluorescamine. Recoveries were quantitative (98-109%) and matrix-independent, no concentration of the extracts was required, the microextraction took about 30 min and several samples could be simultaneously treated.

Supramolecular solvents in solid sample microextractions: application to the determination of residues of oxolinic acid and flumequine in fish and shellfish.

Supramolecular solvents are here proposed firstly as extractants in solid sample microextractions. The approach was evaluated by extracting flumequine (FLU) and oxolinic acid (OXO), two widely used veterinary medicines, from fish and shellfish muscle using a supramolecular solvent made up of decanoic acid (DeA) reverse micelles. The antibiotics were extracted in a single step (approximately 15 min), at room temperature, using 400 microL of solvent.

Determination of benzimidazolic fungicides in fruits and vegetables by supramolecular solvent-based microextraction/liquid chromatography/fluorescence detection.

A supramolecular solvent consisting of vesicles, made up of equimolecular amounts of decanoic acid (DeA) and tetrabutylammonium decanoate (Bu4NDe), dispersed in a continuous aqueous phase, is proposed for the extraction of benzimidazolic fungicides (BFs) from fruits and vegetables. Carbendazim (CB), thiabendazole (TB) and fuberidazole (FB) were extracted in a single step and no clean-up or concentration of extracts was needed. The high extraction efficiency obtained for BFs was a result of the different types of interactions provided by the supramolecular solvent (e.

Supramolecular solvent-based extraction of benzimidazolic fungicides from natural waters prior to their liquid chromatographic/fluorimetric determination.

A supramolecular solvent made up of vesicles of decanoic acid in the nano- and microscale regimes dispersed in a continuous aqueous phase is proposed for the extraction/preconcentration of benzimidazolic fungicides (BFs) from river and underground water samples prior to their determination by liquid chromatography (LC)/fluorimetry. The solvent is produced from the coacervation of decanoic acid aqueous vesicles by the action of tetrabutylammonium (Bu(4)N(+)). Carbendazim (CB), thiabendazole (TB) and fuberidazole (FB) are extracted on the basis of hydrophobic and pi-cation interactions and the formation of hydrogen bonds.

Supramolecular solid-phase extraction of ibuprofen and naproxen from sewage based on the formation of mixed supramolecular aggregates prior to their liquid chromatographic/photometric determination.

Sorbents made up of sodium dodecyl sulphate (SDS) hemimicelles, formed onto gamma-alumina, were proposed for the quantitative and practically solvent-free solid-phase extraction (SPE) of ibuprofen and naproxen from sewage samples. The formation of drug-SDS mixed aggregates was proved by the pseudophase separation model and their composition as a function of the amount of drug was calculated. The overall hemimicellar SPE procedure consumed only 0.

Multifunctional sorbents for the extraction of pesticide multiresidues from natural waters.

In this work multifunctional sorbents, based on surfactant-coated mineral oxides, are assessed for the simultaneous extraction/preconcentration of pesticide multiresidues from aqueous environmental samples. Seventeen pesticides, representative of all the common groups (triazines, phenylureas, carbamates, azols, anilides, chloroacetanilides, organophosphorous, phenoxyacids, aryloxy acids and phenols), are selected for this study. The sorbents assessed are pure sodium dodecyl sulphate (SDS) and mixed tetrabutylammonium (TBA)-SDS hemimicelles and/or admicelles adsorbed onto alumina.

Surfactant to dye binding degree based approach for the selective determination of L-glutamate in foodstuffs.

A selective method for the determination of L-glutamate in foodstuffs has been developed. It was based on the competition established between the analyte and the dye Coomassie brilliant blue G (CBBG) to interact with the surfactant didodecyldimethylammonium bromide (DDABr). The measurement parameter was the amount of DDABr required to reach a given dye-to-surfactant binding degree.

Determination of cationic surfactants in pharmaceuticals based on competitive aggregation in ternary amphiphile mixtures.

The surfactant to dye binding degree (SDBD) method was extended for the first time to the determination of cationic amphiphiles. For this purpose, Cresyl Violet (CV) and sodium dodecylsulphate (SDS) were selected as dye and reactant surfactant, respectively. This chemical system was used for the determination of cationic surfactants in pharmaceuticals.

Assessment of the surfactant-dye binding degree method as an alternative to the methylene blue method for the determination of anionic surfactants in aqueous environmental samples.

The surfactant to dye binding degree (SDBD) method is proposed for the routine monitoring of anionic surfactants in aqueous environmental samples and their analytical features compared with those provided by the standard methylene blue (MB) method. This new analytical approach is based on the effect that anionic surfactants exert on the binding degree of the cationic surfactant didodecyldimethylammonium bromide (DDABr) to the anionic dye Coomassie Brilliant Blue G (CBBG). The formation of DDABr-CBBG aggregates is monitored photometrically.

Pharmaceutical quality control of acid and neutral drugs based on competitive self-assembly in amphiphilic systems.

An aggregation parameter-based methodology for determining acid and neutral drugs in pharmaceutical dosage forms is presented. The method is based on competitive self-assembly in ternary dye-surfactant-drug aqueous mixtures. Dyes bearing charge of opposite sign to that of surfactants bind to surfactant to form mixed dye-surfactant aggregates, which are monitored from changes in the spectra features of the dye.

Determination of bisphenols in sewage based on supramolecular solid-phase extraction/liquid chromatography/fluorimetry.

Supramolecular sorbents (hemimicelles/admicelles) are proposed for the extraction/preconcentration of bisphenols from aqueous environmental samples prior to their liquid chromatography/fluorimetric determination. A comparative study on the use of cetyltrimethylammonium bromide (CTABr)-coated silica and sodium dodecyl sulphate (SDS)-coated gamma-alumina as sorbent materials, is presented. Bisphenol A (BPA) and bisphenol F (BPF) were quantitatively retained on CTABr admicelles.

Determination of aromatic hydrotropic drugs in pharmaceutical preparations by the surfactant-binding degree method.

An aggregation parameter-based analytical approach, the surfactant-dye binding degree (SDBD) method, was used, for the first time, to determine aromatic hydrotropic compounds. The anionic dye Coomassie Brilliant Blue G (CBBG) was used as inductor of didodecyldimethylammonium bromide (DDABr) aggregates, whose formation was monitored from changes in the spectral features of the dye. Interactions between hydrotrope and DDABr molecules resulted in a decrease of the degree of binding of the cationic surfactant to CBBG, which was proportional to the concentration of hydrotrope in the aqueous solution.

Surfactant to dye binding degree-based methodology for the determination of ionic amphiphilic compounds.

A new analytical measurement parameter based on the effect of amphiphilic substances on the degree of binding of a surfactant to dye molecules, which induce the formation of surfactant premicellar aggregates, is presented. The theory for dye-surfactant intermolecular interactions in mixed surfactant systems, which assumes a mononuclear model for the formation of dye-induced premicellar aggregates, has been used to derive an expression that provides linear calibrations for the determination of amphiphilic compounds. The dye-surfactant interactions involved have been investigated, and the variables affecting the measurement analytical parameter have been discussed.