Biomedical subjects

C González-Barreiro

Publications and source records attributed to C González-Barreiro.

5 recordsLinked to original sources

PubMed2005

Photochemical studies of a polybrominated diphenyl ethers (PBDES) technical mixture by solid phase microextraction (SPME).

In this work the photochemical behaviour of a technical mixture of polybrominated diphenyl ethers (PBDEs) (BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154) has been studied. The mixture of BDEs was extracted from aqueous solutions using SPME fibers that were subsequently exposed to different UV irradiation times, procedure so-called Photo-SPME. PBDEs photochemical studies in such medium have been accomplished for the first time. Twenty one different photoproducts, all of them generated by successive bromine atoms losses, have been identified, being their photoformation-photodegradation curves easily determined by the Photo-SPME technique.

Bromine↗

PubMed2003

Simultaneous determination of neutral and acidic pharmaceuticals in wastewater by high-performance liquid chromatography-post-column photochemically induced fluorimetry.

An analytical method for the simultaneous determination of acidic and neutral pharmaceutical active compound (PhACs) residues in wastewater has been developed based on the combination of high-performance liquid chromatography (HPLC) and photochemically induced fluorimetry. The photoderivatization conditions for each particular PhAC have been assessed. Off-line optimization of the HPLC separation for both neutral and acidic compounds has been utilised and evaluated. Detection limits in the low ng/ml range have been achieved without sample pretreatment. By applying the developed analytical method combined with solid-phase extraction to real wastewater samples an enrichment factor of approximately two orders of magnitude can be obtained.

Chromatography, High Pressure Liquid↗

PubMed2002

Photolysis of polychlorinated biphenyls by solid-phase microextraction. "On-fibre" versus aqueous photodegradation.

The photodegradation kinetics of polychlorinated biphenyls "on-fibre" is described. The utilisation of solid-phase microextraction (SPME) fibres to monitor photolysis pathways and determine photoproducts constitutes a new approach that exploits the solvent-free aspect and concentration possibilities of this technique. Direct photolysis of aqueous solutions containing polychlorinated biphenyls (PCBs) was also undertaken and SPME was used in this case for photoproduct extraction purposes. Reductive dechlorination was the main decomposition mechanism in both procedures. Less-chlorinated biphenyls are the principal photoproducts and, among these, some toxic coplanar species have been detected. The influence of irradiation time was evaluated for both treatments. SPME was found to be a good choice for the extraction of photoproducts in experiments conducted in the classical way (extraction after photolysis). Moreover, it is demonstrated that photolysis of PCBs "on fibre" is realistic and provides the possibility of evaluating the phototransformation of these pollutants at environmental levels.

Mass Spectrometry↗

PubMed2002

On-fibre photodegradation studies of polychlorinated biphenyls using SPME-GC-MS-MS: a new approach.

The known advantages of solid-phase microextraction as a simple, one-step, rapid and solvent free extraction technique are exploited to study the photodegradation kinetics of polychlorinated biphenyls "on-fibre". The obtained results show the possibilities of this new approach not only to monitor the photolysis pathways of such compounds but to determine the photoproducts produced at different irradiation times and/or wavelengths. Photoproducts of PCB decomposition were less chlorinated biphenyls, among them some coplanar congeners have been found, which is important from a toxicological point of view.

Environmental Pollutants↗

PubMed2000

Optimisation of alachlor solid-phase microextraction from water samples using experimental design.

We have tested screening and response surface experimental designs to optimise the solid-phase microextraction (SPME) of the widely used herbicide alachlor. Extraction time and sample volume were the only statistically significant factors from those studied. In the final optimised conditions the procedure was applied to the SPME-HPLC analysis of alachlor in spiked water samples with excellent figures of merit.

Acetamides↗