It is proposed to investigate fundamental and engineering aspects of a novel micro gas chromatography (GC) system using capillary-based optical ring resonators (CBORRs) for rapid, highly sensitive and accurate explosive detection and identification. The long-term goal is to leverage research in photonic sensors, microfluidics, microfabrication, bio/chemical sensing, and GC to develop next-generation portable explosive detectors for applications in battlefield and homeland security. Toward this end, there are four specific objectives: 1. Systematic fabrication, theoretical analysis, and experimental characterization of the CBORR sensor; 2. Construction and characterization of the laboratory GC system based on CBORR; 3. Validation of rapid and sensitive detection of explosives from matrix samples; 4. Education of students at the high school, undergraduate, and graduate levels through various training venues. Intellectual Merit: The proposed GC utilizes thin-walled micro-sized glass capillaries whose interior surface is coated with the stationary phase for gas separation. The circular cross section of the capillary forms a series of optical ring resonators capable of detecting analytes flowing in the capillary. This novel sensing architecture combines (1) separation and analysis power of GC; (2) high sensitivity and on-column array detection of optical ring resonators; and (3) excellent fluid handling capability inherent to capillaries, thus enabling sensitive (< 1 picogram) and accurate identification of explosives from highly interfering background with extremely high speed (< 3 second) and minimal false positives. The device developed through the proposed research will provide dramatic improvements in the speed, chemical discrimination, and range of analytes of field-deployable explosive detectors. It will also have a wide range of applications in environmental monitoring, analytical chemistry, and health care. The team involves both academia (University of Missouri Columbia) and industry (ICx Nomadics). Broader Impact: Through the internship program at Nomadics, students will have an excellent opportunity to conduct research in an industrial setting. Several undergraduate courses are under development to introduce research frontiers in bio/chemical sensing to students. The investigators will make use of existing campus program to involve underrepresented student groups in the research. Outreach to K-12 schools will be expanded to involve more high school students in lab research.
