| Title: | Nanoparticle-coated micro-optofluidic ring resonator as a detector for microscale gas chromatographic vapor analysis |
| Author(s): | Scholten K; Collin WR; Fan X; Zellers ET; |
| Address: | "Applied Physics Program, University of Michigan, Ann Arbor, MI, USA 48109-1040" |
| ISSN/ISBN: | 2040-3372 (Electronic) 2040-3364 (Linking) |
| Abstract: | "A vapor sensor comprising a nanoparticle-coated microfabricated optofluidic ring resonator (muOFRR) is introduced. A multilayer film of polyether functionalized, thiolate-monolayer-protected gold nanoparticles (MPN) was solvent cast on the inner wall of the hollow cylindrical SiOxmuOFRR resonator structure, and whispering gallery mode (WGM) resonances were generated with a 1550 nm tunable laser via an optical fiber taper. Reversible shifts in the WGM resonant wavelength upon vapor exposure were detected with a photodetector. The muOFRR chip was connected to a pair of upstream etched-Si chips containing PDMS-coated separation mucolumns and calibration curves were generated from the peak-area responses to five volatile organic compounds (VOCs). Calibration curves were linear, and the sensitivities reflected the influence of analyte volatility and analyte-MPN functional group affinity. Sorption-induced changes in film thickness apparently dominate over changes in the refractive index of the film as the determinant of responses for all VOCs. Peaks from the MPN-coated muOFRR were just 20-50% wider than those from a flame ionization detector for similar mucolumn separation conditions, reflecting the rapid response of the sensor for VOCs. The five VOCs were baseline separated in <1.67 min, with detection limits as low as 38 ng" |
| Notes: | "PubMed-not-MEDLINEScholten, K Collin, W R Fan, X Zellers, E T eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2015/05/06 Nanoscale. 2015 May 28; 7(20):9282-9. doi: 10.1039/c5nr01780g. Epub 2015 May 5" |
