Portable stir membrane device for on-site environmental sampling and extraction

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 μg/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.