• Universitat de València

• Mireia Gómez Egea

The solid phases commonly used in the sampling of Volatile Organic Pollutants (VOCs) often present problems in the retention and recovery of the analytes of interest, due to their loss through volatilisation or chemical decomposition. Furthermore, a post-treatment of the sample is necessary to recover the VOCs. The synthesis of solid phases comprising silica and cyclodextrins (CDs) requires several steps, such as the need for an intermediate compost to connect them, which implies a reduction in their adsorption capacity. It is also necessary to subsequently eliminate CDs in order to recover the analytes. In the case of hygroscopic adsorbents such as silica gel, high humidity conditions can displace the adsorbed pollutants, and in the presence of some reactive gases can lead to the alteration of the analytes. Likewise, these solid phases require toxic and pollutant compounds for desorption to take place, such as CS2.

Researchers at the Universitat de València have developed a new procedure for the synthesis of a new solid phase for the retention of VOCs, which allows the efficient and effective collection of VOC samples and the recovery of the analysis for subsequent analysis in a simple way. The collection of VOCs is obtained in a short period of time and is more economical compared to known procedures. The new hybrid (silica and CD-based) microporous compost can be used as a solid phase or as a filler in samplers to capture VOCs. The retention of the pollutants is less dependent on environmental conditions, such as temperature and/or humidity, than that of commercial samplers, and the recoveries obtained make them suitable for the evaluation of exposure to these pollutants in the workplace. This invention presents an improved alternative to the commercial samplers present in the state of the art that use silica gel or active carbon as solid phases.

The main areas of application of the technology are:

• In the environmental control sector: For the construction of active or passive VOC samplers, for the sampling of pollutants in the atmosphere.
• In the field of industrial hygiene: For the control of pollutants in the workplace atmosphere.

The main advantages of the invention are:

• Simplicity and reproducibility in the synthesis of the new compost, since the synthesis process comprises a single step, does not require the removal of CDs and does not present intermediate compounds between silica and CDs.
• It allows accessibility to VOCs without post-cap treatment.
• Adaptability of the compost to the requirements of each sampler, adapting the size of the grains by using a large number of suitable sizes.
• It is a cleaner, safer and more economical process, as it reduces the generation of toxic waste, as well as the risk of contamination of the operators.
• It reduces the analysis time because the desorption of the pollutants retained in the samplers can be thermal.
• Retention of pollutants more independent of environmental conditions.

• Patent granted