RESUMEN
A portable device that integrates sampling and extraction is proposed in this work. The unit is fabricated using commercial and standardized elements which guarantees the construction reproducibility. Also, it is simple to be mounted and on-site deployed making possible the multi-site sampling. The device uses a commercial nylon membrane as extraction phase for the isolation of the target compounds, but it can be adapted to other flat sorptive phases thus expanding the applicability. Once mounted, the unit is stirred into the sample by means of a portable drill enhancing in that way the diffusion of the target analyte towards the extraction phase. The hydrodynamic behavior and the design have been optimized and the device has been finally used for the extraction benzophenones from swimming pool samples. These endocrine disruptive compounds are determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) at concentrations as low as 0.1⯵g/L with precision, expressed as relative standard deviation, better than 9.9%. The accuracy, calculated as relative recovery, was in the range from 74 to 111 % thus being considered appropriate.
Asunto(s)
Monitoreo del Ambiente/instrumentación , Monitoreo del Ambiente/métodos , Membranas Artificiales , Benzofenonas/análisis , Cromatografía Liquida , Reproducibilidad de los Resultados , Piscinas , Espectrometría de Masas en Tándem , Contaminantes Químicos del Agua/análisisRESUMEN
In this paper, ionic liquid coated magnetic nanoparticles (IL-MNPs) have been prepared by covalent immobilization. The as-synthesized MNPs have been successfully used as sorbent for the extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples, the analytes being finally determined by gas chromatography/mass spectrometry. The influence of several experimental variables (including the ionic strength, amount of MNPs, sample volume, agitation time and desorption solvent) has been considered in depth in the optimization process. The developed method, which has been analytically characterized under its optimal operation conditions, allows the detection of the analytes in the samples with method detection limits in the range from 0.04µgL(-1) (fluoranthene) to 1.11µgL(-1) (indeno(1,2,3-cd)pyrene). The repeatability of the method, expressed as relative standard deviation (RSD, n=7), varies between 4.0% (benzo[b]fluoranthene) and 8.9% (acenaphthene), while the enrichment factors are in the range from 49 (naphthalene) to 158 (fluoranthene). The proposed procedure has been applied for the determination of thirteen PAHs in water samples (tap, river, well and reservoir ones) with recoveries in the range from 75 to 102%.