Development of new silica-based sorption phase with immobilized ionic liquids | Faculty of Chemistry at the Gdańsk University of Technology

Water is the medium containing a huge number of different chemical compounds. Some of them present in excessive amounts may be harmful to the environment and human health. For this reason, drinking water must meet the standards for different water classes (Water Framework Directive in 2000). Therefore, it becomes increasingly important to monitor accurately the content of selected groups of chemical compounds in water samples from different sources. For this purpose, tools that allow quick, cheap and accurate measurement of the concentration of harmful substances in the water samples are needed. Most of the environmental samples requires the sample preparation step. Solid phase microextraction technique (SPME) is the best solution at this stage. This technique is characterized by simplicity and has number of advantages that allow for extraction of a wide range of analytes from samples characterized by a complex matrix composition. One of the major problems for the SPME technique is the extraction of polar analytes from samples characterized by similar polarity of the matrix. Commercially available fibers with polar character have limited applications in samples of complex composition due to the extraction mechanism which is based on specific interactions between analyte and adsorbent. As a result, obtaining low detection limits and wide linearity range is limited.

This project involves the development and evaluation of innovative solution in the field of SPME technique. The concept is strongly related to the development of new coatings for SPME fibers, alternative to those commercially available. It is based on the application of ionic liquids (immobilized in the gel structure) as a sorption phases for SPME. Ionic liquids (ILs) are one of the most popular topics among scientists in recent years. ILs already found many applications in the field of analytical chemistry, such as green solvents, which is caused by their unique physicochemical properties i.e. negligible vapor pressure, non-flammability, high thermal stability and affinity for a wide range of different chemical compounds. Isolation of analytes by dissolving them in extracting phase (ionic liquid) will enable the thermal desorption of analytes at low temperatures (this allow to avoid the risk of decomposition of unstable at higher temperatures compounds ). According to our original idea, the fiber is coated with ionogel (a mixture of ionic liquid and silica).

The plan of the project will include the implementation of the following steps:

• selection of a suitable ionic liquid based on the following parameters: melting point, viscosity, thermal stability and polarity,
• optimization of the conditions of preparation of a gel with the highest content of the ionic liquid;
• coating process of glass fibers by prepared sorption phase (ionogel); evaluation of chemical structure and surface of the fibers will be obtained by Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS);
• investigation of the applicability of the prepared extraction fibers for enrichment of desired analytes from environmental samples (waste water, surface water or drinking),
• validation of developed analytical procedure and comparison with commercially available SPME fibers.

The application of ionic liquids with the sol-gel technique for SPME fiber coatings preparation, which stands for the main objective of this project, brings novelty to analytical chemistry. Moreover, obtaining a mechanically stable layer of ionogel on the SPME fiber, characterized by extraction of the absorbing mechanism, may be described as innovative element of the project as well. Reaching the values of limits of detections for the analytes in the original matrix at ppb level will provide the investigated solution efficient, environmentally friendly analytical tool for monitoring environmental pollutants in water samples. This innovative solution of the application of new sorption phase for SPME technique applied for isolation of environmental pollutants from water samples, will provide the basic information necessary for the reliable assessment of the state of the environment and changes therein, and will help to raise environmental awareness among the general public.