Supramolecular solvent-based high-throughput sample treatment platform for the biomonitoring of PAH metabolites in urine by liquid chromatography-tandem mass spectrometry.

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), present in human urine at trace concentrations (viz. from ng L to μg L), are considered the main biomarkers of human exposure to PAHs. In this work, we report a simple and high-throughput sample treatment platform to facilitate the biomonitoring of OH-PAHs by making it easier, greener and most cost-effective.

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.

Single-step extraction and cleanup of bisphenol A in soft drinks by hemimicellar magnetic solid phase extraction prior to liquid chromatography/tandem mass spectrometry.

Hemimicelles of tetradecanoate chemisorbed onto magnetic nanoparticles (MNPs) are here proposed as a sorbent for the single-step extraction and cleanup of bisphenol A (BPA) in soft drinks. The purpose of this work was to develop a simple, rapid and low-cost sample treatment suitable to assess the human exposure to BPA from this type of high consumption food. The nanoparticles were easily coated by mixing commercially available magnetite of 20-30 nm mean particle diameter with tetradecanoate at 85°C for 30 min.

Determination of urinary bisphenol A by coacervative microextraction and liquid chromatography-fluorescence detection.

Total (free plus conjugated) urinary BPA is currently being used to assess human exposure to this contaminant. This work proposes the use of coacervates made up of reverse micelles of decanoic acid for the microextraction of BPA, prior to its determination by liquid chromatography and fluorescence detection (lambda(ex)=276 nm and lambda(em)=306 nm), with the aim of simplifying sample treatment and reducing analysis time and costs in epidemiologic studies. The procedure involves the enzymatic hydrolysis of 7 mL of urine and then the addition of decanoic acid (100mg) and tetrahydrofurane (1 mL), conditions under which the coacervate (extractant phase, approximately 167 microL) forms in situ and instantaneously.

Decanoic acid reverse micelle-based coacervates for the microextraction of bisphenol A from canned vegetables and fruits.

Decanoic acid reverse micelle-based coacervates were proposed for the extraction of bisphenol A (BPA) from canned vegetables and fruits prior to its determination by liquid chromatography and fluorescence detection at lambda(exc) = 276 nm and lambda(em) = 306 nm. The procedure involved the extraction of minute quantities (300-700 mg) of homogenized food sample with an aqueous solution containing 10% of THF and 0.5% of decanoic acid, conditions under which the coacervate (around 340 microL) formed in situ and instantaneously.

Study of the influence of water matrix components on admicellar sorbents.

Hemimicelle-based and/or admicelle-based solid-phase extraction (SPE) has recently been proved to be a fruitful strategy for the extraction and concentration of a wide variety of organic pollutants. This research focus on the effect of river and wastewater matrix components on the adsorption of sodium dodecyl sulfate (SDS) onto alumina, which is the most-used sorbent in hemimicelle-based and/or admicelle-based SPE, and we discuss the analytical consequences of the modifications observed. The effect of electrolytes (0.

Analysis of linear alkylbenzene sulfonate homologues in environmental water samples by mixed admicelle-based extraction and liquid chromatography/mass spectrometry.

Hemimicelles and admicelles of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC), adsorbed onto silica, were tested as sorbents for the solid phase extraction (SPE) of linear alkylbenzene sulfonate (LAS) homologues from environmental water samples. LASs were quantitatively retained on both surfactants due to high hydrophobic and ionic interactions, which led to the formation of analyte-extractant mixed aggregates. Parameters affecting the SPE of LASs were optimised.

Hemimicelle-based solid-phase extraction of estrogens from environmental water samples.

Hemimicelles and admicelles of sodium dodecyl sulfate (SDS) on alumina and cetyltrimethyl ammonium bromide (CTAB) on silica were evaluated for the concentration and purification of the priority estrogens estrone (E(1)), 17beta-estradiol (E(2)) and ethynylestradiol (EE(2)) from sewage and river samples. Retention was based on analyte-sorbent hydrophobic and cation-pi interactions. Parameters affecting the SPE of estrogens on both types of sorbents were comparatively investigated.

Boron deficiency causes accumulation of chlorogenic acid and caffeoyl polyamine conjugates in tobacco leaves.

The effects of boron (B) deficiency on carbohydrate concentrations and the pattern of phenolic compounds were studied in leaves of tobacco plants (Nicotiana tabacum L.). Plants grown under B deficiency showed a notable increase in leaf carbohydrates and total phenolic compounds when compared to controls.

Differentiation and quantification of linear alkyl benzenesulfonate isomers by liquid chromatography-ion-trap mass spectrometry.

Discrimination and quantitation of the 20 positional isomers of C10-C13 linear alkyl benzenesulfonates (LASs), based on the use of reversed-phase liquid chromatography-electrospray ionisation in negative ion mode ion-trap mass spectrometry, was undertaken. Discrimination was achieved by LAS MS-MS analysis into the ion trap, by monitoring specific fragment ions resulting from the benzylic cleavage of the carbon alkyl chain on both side of the LAS phenyl group. Parameters affecting the electrospray ionisation source and the ion-trap operation were optimised.

H2O2/TiO2 photocatalytic oxidation of metol. Identification of intermediates and reaction pathways.

The applicability of H2O2 to increase the efficiency of TiO2 photocatalytic degradations was investigated. The photographic developer metol [N-methyl-p-aminophenol] that does not adsorb on the surface of TiO2 particulates was used as a model for this purpose. It was proved that metol was mineralised under oxidation with H2O2/TiO2/UV through different thermal and photochemical reactions.

Identification of the main by-products of the developing agent N-hydroxyethyl-N-ethyl-3-methyl-p-phenylenediamine in photographic effluents by liquid chromatography/mass spectrometry.

N-Hydroxyethyl-N-ethyl-3-methyl-p-phenylenediamine (CD(4)) is commonly used as a developing agent in color photographic processes. The main by-products formed in developer baths used in the process were separated and identified by liquid chromatography/electron ionization mass spectrometry (LC/EI-MS) and liquid chromatography/atmospheric pressure ionization mass spectrometry (LC/API-MS). A number of side reactions, in addition to the main reactions involved in the developing process, were found to occur.