Elisa Rubí

• University of Santiago de Compostela

A low solvent consumption method for the determination of eight ultraviolet (UV) filters, displaying low to medium polarities, in freeze-dried samples of marine bivalves and fish is proposed. Matrix solid-phase dispersion (MSPD) and gas chromatography with mass spectrometry (GC-MS) were used as sample preparation and determination techniques, respe...

Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of ei...

This work describes an effective, low solvent consumption and affordable sample preparation approach for the determination of eight UV filters in surface and wastewater samples. It involves sorptive extraction of target analytes in a disposable, technical grade silicone disc (5 mm diameter × 0.6 mm thickness) followed by organic solvent desorption,...

This work presents an effective sample preparation method for the determination of eight UV filter compounds, belonging to different chemical classes, in freeze-dried sludge samples. Pressurized liquid extraction (PLE) and gas chromatography-mass spectrometry (GC-MS) were selected as extraction and determination techniques, respectively. Normal-pha...

The performance of the dispersive liquid–liquid microextraction (DLLME) technique for the determination of eight UV filters and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After extraction, analytes were determined by gas chromatography combined with mass spectrometry detection...

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A novel, single step method for the determination of seven ink photo-initiators in carton packed milk samples is described. Solid-phase microextraction (SPME) and gas chromatography (GC), combined with mass spectrometry (MS), were used as sample preparation and determination techniques, respectively. Parameters affecting the performance of the micr...

A procedure for the determination of six derivatives of 2-hydroxybenzophenone, used as UV absorbers, in water samples is presented. Compounds were first concentrated using a solid-phase extraction (SPE) cartridge and then selectively determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using electrospray ionization (ESI). The eff...

A novel approach for the determination of seven fungicides (metalaxyl-M, penconazole, folpet, diniconazole, propiconazole, difenoconazole and azoxystrobin) in wine samples is presented. Analytes were extracted from the matrix and transferred to a small volume of a high density, water insoluble solvent using solid-phase extraction (SPE) followed by...

A simple, inexpensive sample preparation procedure, based on the matrix solid-phase dispersion (MSPD) technique, for the determination of six UV filters: 2-ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 3-(4-methylbenzylidene) camphor (4-MBC), isoamyl-p-methoxycinnamate (IAMC), 2-ethylhexyl-p-methoxycinnamate (...

A sensitive procedure for the determination of three UV filters: ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 2-hydroxy-4-methoxybenzophenone (BP-3) and two related hydroxylated benzophenones (2,4-dihydroxybenzophenone, BP-1 and 2,2'-dihydroxy-4-methoxybenzophenone, BP-8) in water samples is presented. Analyt...

A fast and novel sample preparation procedure for the determination of triclosan (TCS) and methyltriclosan (MTCS) in water samples is presented. Dispersive liquid–liquid microextraction, using a ternary mixture consisting of a disperser, an extractant and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) as derivatization reagent, wa...

The applicability of disposable polypropylene microporous membranes (MMs) for the concentration of five halogenated anisoles in water samples was investigated. Two microextraction approaches, named MM solid-phase extraction (MMSPE) and liquid-liquid extraction (MMLLE), are proposed. They are based on adsorption of target species onto the surface of...

An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combi...

This work studies the stability of three UV filters: 2-ethylhexyl salicylate (ES), 2-ethylhexyl 4-(dimethylamino) benzoate (EHPABA) and 2-hydroxy-4-methoxybenzophenone (BP-3), in water samples containing low concentrations of free chlorine. Moreover, 2,4-dihydroxybenzophenone (2,4-DHBP), a metabolite of BP-3, was also included in some of the perfor...

An alternative sorptive microextraction method for the determination of five halogenated anisoles in water and wine matrices is proposed. Analytes were concentrated in an inexpensive and disposable piece of bulk polydimethylsiloxane (PDMS), desorbed with a small volume of organic solvent, and determined by gas chromatography with electron-capture d...

A sample preparation method based on the use of pressurized liquid extraction is proposed for the determination of four alkyl parabens and triclosan in indoor dust. Extraction of analytes and removal of interfering species were achieved in the same step, by placing an appropriate sorbent in the extraction cell and by choosing a right combination of...

The suitability of an inexpensive polydimethysiloxane (PDMS) sorbent, produced on an industrial scale, for the extraction of polybrominated diphenyl ethers (PBDEs), from tetra- to hexabrominated congeners, from water samples was assessed. Experiments were carried out using samples spiked with a pentabromo diphenyl ether (pentaBDE) mixture, PDMS rod...

A simple sample preparation method for the determination of four parabens and triclosan in indoor dust is presented. Analytes were extracted from the sample and isolated from interfering species using the matrix solid-phase dispersion technique. After that, they were silylated and determined by gas chromatography combined to tandem mass spectrometr...

Chemical transformations of four alkyl esters of p-hydroxybenzoic acid, parabens, in chlorinated water samples are investigated. Quantification of the parent species and identification of their reaction by-products were performed using gas chromatography in combination with mass spectrometry. Experiments were accomplished considering free chlorine...

A rapid method for the screening of polychlorinated biphenyls (PCBs) in sediment samples is described. Analytes are concentrated on a poly(dimethylsiloxane) (PDMS) solid-phase microextraction (SPME) fibre, separated using a narrow-bore gas chromatography column (10 m x 0.1mm I.D.) and determined with a micro-electron-capture detector (micro-ECD). T...

A procedure for the determination of five esters of p-hydroxybenzoic acid (parabens) in water samples is presented. Analytes (methyl, ethyl, propyl, butyl and benzyl paraben) are concentrated on a solid-phase microextraction (SPME) fibre, converted on their tert-butyldimethylsilyl derivatives and selectively determined using gas chromatography in c...

The feasibility of solid-phase microextraction (SPME) for the determination of several organophosphorus flame retardants and plastizicers in water samples by gas chromatography-nitrogen phosphorous detection (GC-NPD) is evaluated. These compounds have a wide range of polarities and volatilities and require a thorough optimisation of the different S...

The degradation of 2-(2,4-dichlorophenoxy)-5-chlorophenol (triclosan) in chlorinated water samples was investigated. Sensitive determination of the parent compound and its transformation products was achieved by gas chromatography with mass spectrometry detection after sample concentration, using a solid-phase extraction sorbent and silylation of t...

A procedure for the determination of 2-(2,4-dichlorophenoxy)-5-chlorophenol (Triclosan) and two possible transformation compounds, 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP), in sludge from sewage treatment plants (STP) and sediments is presented. Extraction was performed using an acetone:methanol (1:1) mixture under the act...

A low cost method for the screening of six polybrominated diphenyl ethers (PBDEs) and seven polychlorinated biphenyls (PCBs) in biological samples containing up to 100% of fat is presented. Compounds are extracted from the sample and isolated from lipids using a matrix solid-phase dispersion (MSPD) cartridge and 20 ml of n-hexane as elution solvent...

A solid-phase microextraction (SPME) method for the determination of triclosan, methyl triclosan, 2,4-dichlorophenol and 2,3,4-trichlorophenol (considered as possible triclosan metabolites) in water samples was optimised. Analytes were first concentrated on a SPME fibre, directly exposed to the sample, and then triclosan and the two chlorinated phe...

In this work a solid-phase microextraction (SPME) method for the determination of eight phenoxy acid herbicides and dicamba in water samples has been developed. Analytes are concentrated on a SPME fibre, on-fibre silylated using N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), and determined by gas chromatography with mass spectro...

In the present work a sequential injection analysis system is proposed for the determination of mercury by cold vapor atomic absorption spectrometry. Both the sample and the reagent are sequentially aspirated using a Crison automatic Compact Titrator and impelled into a gas–liquid separation cell. Once there, a N2 flow sweeps the reduced mercury in...

A sequential injection analysis (SIA) assembly for the atomic absorption determination of Fe(III) in natural waters is proposed. Iron is preconcentrated on a microcolumn packed with a chelating resin (Chelex 100) that is inserted in the manifold. The sample is passed through the column and the iron retained by the resin is subsequently eluted with...

A sequential injection analysis (SIA) assembly for the photometric determination of Fe(III) in fresh- and seawater is proposed. Iron is preconcentrated on a microcolumn packed with a chelating resin (Chelex 100) that is inserted in the manifold. The sample is passed through the column, and the iron retained by the resin is subsequently eluted with...

A study of the total mercury and methylmercury distribution in esturine sediments is presented. Core sediments obtained in a polluted area were freeze-dried and sieved to obtain four fractions. Fraction 1, having grain size <0.30 mm; Fraction 2, having grain size <0.30 mm; Fraction 3, with grain size <1 mm and Fraction 4, having particle size >1 mm...

In the application of GC ECD procedures for methylmercury analysis and organomercury speciation, frequent column-treatments must be carried out to maintain the analytical system under statistical control. Often the decision to carry out a new treatment is taken without any statistical assistance. Several quality control techniques have been applied...

A rapid method for speciation and determination of organomercury compounds in biological samples of marine origin using Capillary Electrophoresis (CE) is reported. Organomercurials were extracted from the samples by means of the classical Westöö procedure thus giving organomercury-cysteine complexes which can be separated from each other by means o...

A programmed temperature gas chromatographic method is presented by which it is possible to carry out routine analysis of methyl mercury in biological samples prepared according to the AOAC official first action recommendations without the need for preliminary treatment of the columns. This method greatly extends the life of the columns as well as...

The factors determining the effective life of the capillary columns commonly used in the determination of organomercury compounds in biological and environmental materials were examined. The effects of pretreatment of these columns with mercury(II) salts on their behaviour and the duration of the treatments in terms of the type of stationary phase...

Four studies on organo-mercury compounds speciation carried out in the analytical chemistry laboratory of the University of Santiago are briefly described and discussed. Search for new methods of separation based on liquid chromatography as well as quality control and application studies have been started and the results obtained up to the end of 1...

The results of the first sampling campaign for Mercury speciation in the Pontevedra estuary (Spain) are presented. Attempts have been made to correlate the behaviour of inorganic and methyl‐mercury in sediments close waste waters treatment system and the location of the dumping point.