Multifunctional vesicular coacervates as engineered supramolecular solvents for wastewater treatment.

In this study, multifunctional supramolecular solvents (SUPRASs) able to simultaneously extract ionic, polar and hydrophobic organic compounds from wastewater have been developed. SUPRASs were synthesized in aqueous solutions containing mixtures of carboxylic acids and carboxylates that underwent spontaneous self-assembly and coacervation under the addition of tetraalkylammonium ions. These SUPRAS consisted of coacervate droplets made up of large unilamellar vesicular aggregates bridged by tetraalkylammonium ions.

Restricted access supramolecular solvents for sample treatment in enzyme-linked immuno-sorbent assay of mycotoxins in food.

A restricted access supramolecular solvent (SUPRAS-RAM) made up of tetradecanoic acid reverse micelles is proposed as a wide-scope and low-cost strategy for the treatment of agrifood samples prior to enzyme-linked immunosorbent assays (ELISA). The approach was assessed for the determination of ochratoxin A (OTA) in wines and spices and aflatoxin B1 (AFB1) in cereals, two ubiquitous mycotoxins that were selected as representative contaminants for this study. The samples were selected to cover a variety of matrices in terms diverse composition and high complexity.

Simultaneous determination of α-, β- and γ-hexabromocyclododecane diastereoisomers in water samples by isotope dilution mass spectrometry using (81)Br-labeled analogs.

This work describes the synthesis, characterization and application of three (81)Br-labeled diastereosiomers of hexabromocyclododecane (HBCD) for the accurate and precise determination of α-, β- and γ-HBCD in water samples by isotope dilution mass spectrometry. The synthesis of the labeled analogs was carried out by bromination of cis, trans, trans-1,5,9-cyclododecatriene with (81)Br-enriched bromine. After isolation and purification by semipreparative HPLC, each diastereoisomer was characterized in terms of concentration and isotopic enrichment.

Restricted access supramolecular solvents for removal of matrix-induced ionization effects in mass spectrometry: Application to the determination of Fusarium toxins in cereals.

Ion suppression/enhancement caused by matrix effects continues being a major concern in liquid chromatography-mass spectrometry (LC-MS). This research explores the ability of a supramolecular solvent (SUPRAS) made up of inverted hexagonal aggregates of oleic acid to behave as a liquid with restricted access properties (SUPRAS-RAM). Fusarium toxins in cereals were extracted with the oleic acid-based SUPRAS-RAM prior to their quantification by LC-electrospray ionization (ESI)-ion trap-MS (LC-ESI-IT-MS) in order to investigate the capability of this solvent to remove or reduce ionization suppression and/or enhancement in the analysis of complex samples by MS.

Determination of Polychlorinated Biphenyls in Solid Samples by Isotope Dilution Mass Spectrometry Using ³⁷Cl-Labeled Analogues.

This work describes the first application of (37)Cl-labeled compounds to isotope dilution mass spectrometry (IDMS). The synthesis of 12 (37)Cl-labeled polychlorinated biphenyls (PCBs) was carried out by the chlorination of biphenyl with isotopically enriched chlorine gas, generated by the direct oxidation of Na(37)Cl with potassium peroxymonosulfate. After an exhaustive purification due to the presence of other congeners, the concentration and the isotopic enrichment of all (37)Cl-labeled PCBs in the mixture was determined.

On-line double isotope dilution laser ablation inductively coupled plasma mass spectrometry for the quantitative analysis of solid materials.

We report on the determination of trace elements in solid samples by the combination of on-line double isotope dilution and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The proposed method requires the sequential analysis of the sample and a certified natural abundance standard by on-line IDMS using the same isotopically-enriched spike solution. In this way, the mass fraction of the analyte in the sample can be directly referred to the certified standard so the previous characterization of the spike solution is not required.

Vesicular aggregate-based solventless microextraction of Ochratoxin A in dried vine fruits prior to liquid chromatography and fluorescence detection.

A solventless microextraction was proposed for the development of a simple, fast, low-cost and environmental friendly sample treatment for the determination of Ochratoxin A (OTA) in dried vine fruits. The objective was to offer an alternative to conventional sample treatments, which invariably involve extractions with large solvent volumes followed by clean-up with expensive, not recyclable and limited storage stability immunoaffinity sorbents. The method involved the stirring of 300 mg of dried vine fruit subsamples with 400 μL of a supramolecular solvent (SUPRAS) made up of decanoico acid/tetrabutylammonium decanoate vesicles.

Supramolecular solvent-based microextraction of ochratoxin A in raw wheat prior to liquid chromatography-fluorescence determination.

A supramolecular solvent made up of reverse micelles of decanoic acid, dispersed in a continuous phase of THF:water, was proposed for the simple, fast and efficient microextraction of OTA in wheat prior to liquid chromatography-fluorescence determination. The method involved the stirring of 300 mg-wheat subsamples (particle size 50microm) and 350microL of supramolecular solvent for 15min, subsequent centrifugation for 15min and the direct quantitation of OTA in the extract, previous 5.7-fold dilution with ethanol/water/acetic acid (49.

Coacervative extraction of Ochratoxin A in wines prior to liquid chromatography/fluorescence determination.

Coacervates made up of reverse micelles of decanoic acid were assessed as a new strategy for the simplification of wine sample treatment in the determination of Ochratoxin A (OTA). Simultaneous extraction/concentration of this contaminant was based on both hydrophobic and hydrogen bond OTA:coacervate interactions. Parameters affecting extraction efficiency and concentration factors were studied.