Adjusting Sample Concentration within Dynamic Range for Improved Data Analysis using Vacuum Ultraviolet Automated LibraryIntegrated Deconvolution

Adjusting Sample Concentration within Dynamic Range for Improved Data Analysis using Vacuum Ultraviolet Automated Library-Integrated Deconvolution Shubhneet Warar, Anna Arvidson, Meredith Ehlmann, Nick von Waaden, Ian G. M. Anthony, Touradj Solouki, Ph.D.

Rapid identification of analytes is crucial in forensic, biomedical, and defense applications. Automated data analysis techniques can aid in time-sensitive and accuracy-focused analyte detection. Gas chromatography combined with vacuum ultraviolet spectroscopy (GC-VUV) is a powerful approach for detection of volatile organic compounds. GC-VUV allows for separation and identification of most analytes; however, mixtures of analytes that are not fully separated in the GC dimension can be difficult to analyze. GC-VUV peak convolution occurs when two or more detected analytes are not fully separated and can lead to misidentifications. Deconvolution is a mathematical method to extract the data corresponding to the convoluted analytes, and it can aid in identifying and quantifying convoluted components. We have automated deconvolution of GC-VUV data using a custom-built software package: “Vacuum Ultraviolet Automated Library-Integrated Deconvolution,” abbreviated VALID. In this study, we assess the performance of VALID on GC-VUV data collected from “real-world” essential oil samples.

Samples of frankincense and grapefruit-based essential oil were injected into a GC-VUV instrument and analyzed both manually (via the standard VUV software) and automatically (via VALID). VALID utilized SIMPLISMA-ALS for the deconvolution and R-squared for the library-comparison metric.

VALID succeeded in identifying 24.3% more analytes than manual identification alone (37 with only manual analysis vs. 46 with VALID). In addition, VALID successfully identified analytes that could not be detected by manual inspection (i.e., “hidden” GC peaks such as β-elemene in the grapefruit-based essential oil sample). The accuracy of the VALID-identified analytes was confirmed by GC retention time analysis. Moreover, GC retention time analysis allowed correction of manually miss-assigned GC peaks (viz., octyl acetate and p-propyltoluene, corrected to pentyl acetate and p-isopropyltoluene, respectively). Compared to manual analysis, VALID improved quantitation and reduced the analysis time by about 50%. VALID provided accurate analysis reports, saved time on data mining, and allowed for identification of hidden components present in complex samples. No single experimental trial was effective to yield correct assignments for all unknowns; however, injection of varied sample concentrations allowed for complete coverage of the VUV spectrometer’s dynamic range. More analytes were successfully assigned via the combination of manual VUV analysis, VALID, and GC retention time analysis than utilizing either of the three data analysis approaches alone.

Mosquito Surveillance Techniques and Results in Waco, TX Batool Unar Syed, Carolyn Carper, Henry Lyons, Deborah Olayinka, Jason Pitts, Ph.D.

Mosquitoes are significant vectors for various pathogenic diseases, and due to climate change, some mosquito species may be able to expand into new territories, including Texas. McLennan County is experiencing rapid population growth making mosquito surveillance and dissemination of information about vector-borne diseases of particular interest. Setting up mosquito traps is a necessary public health objective in Texas, especially in the urban areas like Waco. Frequently used trapping methods include odor-baited BGS2 and EVS traps for collecting adults, and mosquito larvae collections from natural pool sites and human created sites such as used tires. After setting multiple traps and examining larvae and adult mosquitoes using microscopy, the most common mosquito species in Waco, Texas were identified. Mosquitoes were further identified by DNA extraction, polymerase chain reaction, and sequencing of a mitochondrial gene. More efficient techniques could be developed to streamline the identification process. Efficient identification of mosquito species and the additional detection of possible pathogens associated with them can help promote public awareness and improve disease prevention in urban settings.