Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Danielle K. Geremia - University of Scranton
Co-Author(s): Nujud Maslamani, Erica Manandhar, and Brian A. Logue, South Dakota State University, Brookings, SD
Trace and ultra-trace analysis can be difficult to achieve, especially for polar, more volatile, and/or thermally unstable analytes. A novel technique, coined ICE Concentration Linked with Extractive Stirrer (ICECLES), may help address this problem. The implementation of ICECLES described here combines stir bar sorptive extraction (SBSE) with freeze concentration (FC), where an aqueous solution is frozen during SBSE in order to concentrate analytes into a polydimethylsiloxane (PDMS) coated stir bar. Five test probe molecules with a range of log Kows (2-butanol, benzyl alcohol, benzaldehyde, dimethyl trisulfide and bromobenzene) were prepared from aqueous solutions using ICECLES. Thermal desorption gas–chromatography mass–spectrometry was then used to quantify these analytes. Parameters affecting the performance of ICECLES (e.g., freeze rate) were evaluated, with extraction at lower speeds resulting in higher extraction efficiencies, whereas the freeze rate and initial analyte concentration only had a minor effect. ICECLES produced much higher extraction efficiencies than SBSE alone, with signal enhancements of up to 474× SBSE. ICECLES also provided excellent reproducibility and lower LODs than SBSE for all compounds tested. ICECLES performed well when used to analyze multiple triazine pesticides and breakdown products in environmental surface waters. Overall, the ICECLES technique was excellent at preparing aqueous samples for trace analysis and shows promise as a novel analytical sample preparation technology.
Funder Acknowledgement(s): Saudi Arabian Cultural Mission (SACM), National Science Foundation through the Green/Environmental REU site (Grant #CHE-1461092); U.S. Joint Executive Office for Chem Bio Defense, Joint Program Management Protection Contract W911SR-09-0059.
Faculty Advisor: Brian A. Logue, email@example.com
Role: Surface water samples collected from Lake Preston, Oakwood Lake, and the Big Sioux River were analyzed using both Stir Bar Sorptive Extraction (SBSE) and ICECLES techniques. Analysis of the stir bars by thermal desorption indicated atrazine in all samples. ICECLES has proven to give higher signal enhancements than SBSE and provide lower limits of detection, which is extremely useful for ensuring the safety of drinking water and ensuring the protection of aquatic ecosystems with a relatively simple apparatus.