| AVS 62nd International Symposium & Exhibition | |
| Accelerating Materials Discovery for Global Competitiveness Focus Topic | Monday Sessions |
| Session MG+2D+MI+NS+TF-MoA |
| Session: | Design and Discovery (Bio and Other Interfaces) |
| Presenter: | Matthew Linford, Brigham Young University |
| Authors: | M.R. Linford, Brigham Young University C.V. Cushman, Brigham Young University B. Singh, Brigham Young University A. Diwan, Brigham Young University |
| Correspondent: | Click to Email |
Solid phase microextraction (SPME) is a solventless, fast, easy and relatively inexpensive sample preparation technique that integrates sampling, extraction and preconcentration of samples such as food, waste water, air, and biological fluids in one step. However, commercial SPME coatings may be expensive, show relatively short lives, extract limited numbers of compounds, and have relatively low thermal and mechanical stability. The aim of this study is to develop an SPME device that is thinner, robust, long lasting, has higher mechanical strength, greater thermal and solvent stability, and is devoid of the other drawbacks of commercial coatings. We describe a new method for the preparation of nanoporous SPME coatings via the oblique-angle sputtering of silicon and subsequent functionalization with silanes. The thickness of the sputtered coatings was controlled by varying the sputtering time. To increase the density of –OH groups on the surfaces, the coatings were treated in piranha solution and then reacted with n-octadecyldimethylmonomethoxysilane to render the surfaces hydrophobic. The coatings were robust and were characterized at each step in the process using XPS, water contact angle goniometry, spectroscopic ellipsometry, and scanning electron microscopy. Our sputtered, silanized fiber yielded comparable and/or better extraction efficiencies than a commercial 7 μm PDMS fiber, especially for higher molecular weight species. In the case of a series of primary alcohols, and aldehydes, our fiber outperformed the commercial PDMS fiber by a factor of 2 – 3. In the evaluation of two real world samples: a sea water extract and beer, our fiber showed unique selectivity. Our 1.1 µm fiber yielded comparable signals to 65 µm PDMS-DVB and 85 µm CAR-PDMS commercial fibers for higher molecular weight analytes. For a ~2.2 µm fiber, the performance of our fiber increased substantially.