LOW-COST SAMPLING APPROACHES FOR MEASURING INDUCED VOCS OF CITRUS

<br>What was accomplished under these goals? Task 1: Automated sample loading and operation Goal: Achieve automated operation with a carousel of 32 samples. The effort with Ascendant Engineering Solutions (AES) was delayed at the start as the funds in the Prime Award to ANI were withheld "pending receipt and approval of supporting justification for salary rates for consultants Ascendant Engineering Solutions ($76,813)". The funds were released on 12/21/2016, about 3 months after the start of the program. We are about 2 months behind - we are catching up with the time lost at the start. Task 1a: Define the requirements: Status: Completed. See Appendix 2 - Proof of Concept Design Review. Task 1b: Engineering approach for sample carousel configuration: Milestone 2: Initial design review. Milestone completed. Task 1c: Design the first carousel prototype AES staff and ANI will work closely to design the sample carousel. AES will work with ANI to test concepts as needed. Milestone 3: Final design review. Milestone completed, see Appendix 2 - Proof of Concept Design Review. Task 1d: Complete first engineering prototype AES will build the sample carousel. AES will also work with ANI to automate the operation of the GC-DMS coupled with the sample carousel. Status: As of July 13, 2017, the initial assembly is 60% completed. Milestone 4: Automatic sample loading from the carousel to the GC-DMS is achieved. Status: In progress. Expect this to be achieved Sept, 2017. Task 2: Increase speed/throughput of instrument Goal: Achieve testing of 96 samples per day (about 15 minutes/sample with 24 hour operation). We will modify one of the instruments delivered earlier to the California CRB (CRB-funded program) to achieve fast automated operation sufficient to commercial viability, accepting the needle sample platform demonstrated in Phase I of this program. The improved instrument and libraries for testing Navel, Lisbon Lemon, and Mandarins (Task 3) will be delivered back to the CA CRB at the end of the program, achieving accuracy of 0.90 or better. Milestone 5: Operation equivalent to 15 minutes per sample is achieved. Status: We have achieved 7 minutes per sample. If we add a "cleaning run" (operate the analysis with no sample present to clean out any residual chemicals), this adds another 7 minutes so total 14 minutes. This is less than 15 minutes milestone; Milestone 5 has been achieved. Task 3: Demonstrate accuracy of > 0.9 Goal: Achieve accuracy of 0.9 or better for California Navel, Lisbon Lemon and Mandarins as well as Texas Rio Red grapefruit and Navel. Task 3a: Library building Status: The work described in this subtask has not started although we took advantage to participate in the California HLB baseline study (CA 1 and CA 1b) supported by the USDA and coordinated by UC Riverside and UC Davis. Through this effort, we have collected 260 needle samples using the etched needles. Initial analysis results are presented in Task 3b. Task 3b: Improve sample analysis software We have refined the set of the biomarkers and tuned their positions to match the VOC peaks for the citrus library built with the etched needles approach. The VOC signatures are further grouped into classes based on the citrus variety, rootstock, disease state (if known). The analysis software is also tested using ample citrus data obtained by CRB partners from different citrus trees in residential areas in California. In addition, we have outlined the architecture of the software needed to integrate the needle sampler with the existing VOC analyzer. This will synchronize the needle delivery to the sampling chamber with the readiness signals from the sensor. Signal enhancement through roughening the surface of the needles: In addition to improving the analysis software, we also tried to improve the signal-noise ratio by roughening the needles used to collect odor samples. At the beginning of the program, we were using standard sewing needles that were cleaned. We examined to processes for roughening the surface of the needle to increase the odor signal from the sample. Significant signal increase was achieved by electrochemical etching the needles to roughen the surface. Task 3c: Blind study Milestone 6: Achieve accuracy of > 0.9. Status: No work started yet per schedule. Task Responsibility: Dr. Fink will be responsible for directing this study, assisted by Chip Thuesen and Dr. Pavlovsky (ANI) and Prof. Cristina Davis of UC Davis. Dr. Pavlovsky will be responsible for software development. Task 4: Contract manufacturing Goal: Demonstrate that the GC-DMS equipment can be built for $75,000 or less. Task Responsibility: Dr. Fink will be responsible for this effort. Milestone 7: Achieve a cost per instrument of <br><b>Publications</b><br>