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Browsing by Author "McKenna, Josiah"
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Item Detection of chemical warfare agent simulants and hydrolysis products in biological samples by paper spray mass spectrometry(RSC, 2017-05) McKenna, Josiah; Dhummakupt, Elizabeth S.; Connell, Theresa; Demond, Paul S.; Miller, Dennis B.; Nilles, J. Michael; Manicke, Nicholas E.; Glaros, Trevor; Chemistry and Chemical Biology, School of SciencePaper spray ionization coupled to a high resolution tandem mass spectrometer (a quadrupole orbitrap) was used to identify and quantitate chemical warfare agent (CWA) simulants and their hydrolysis products in blood and urine. Three CWA simulants, dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), and diisopropyl methylphosphonate (DIMP), and their isotopically labeled standards were analyzed in human whole blood and urine. Calibration curves were generated and tested with continuing calibration verification standards. Limits of detection for these three compounds were in the low ng mL−1 range for the direct analysis of both blood and urine samples. Five CWA hydrolysis products, ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), isobutyl methylphosphonic acid (iBuMPA), cyclohexyl methylphosphonic acid (CHMPA), and pinacolyl methylphosphonic acid (PinMPA), were also analyzed. Calibration curves were generated in both positive and negative ion modes. Limits of detection in the negative ion mode ranged from 0.36 ng mL−1 to 1.25 ng mL−1 in both blood and urine for the hydrolysis products. These levels were well below those found in victims of the Tokyo subway attack of 2 to 135 ng mL−1. Improved stability and robustness of the paper spray technique in the negative ion mode was achieved by the addition of chlorinated solvents. These applications demonstrate that paper spray mass spectrometry (PS-MS) can be used for rapid, sample preparation-free detection of chemical warfare agents and their hydrolysis products at physiologically relevant concentrations in biological samples.Item Paper Spray-Mass Spectrometry Coupled with Pressure Sensitive Adhesive-Based Collection for the Recovery and Detection of Drugs of Abuse(2023-08) Prunty, Sarah G.; Manicke, Nicholas; Goodpaster, John; McKenna, JosiahIllicit drug abuse is a widespread issue in the United States and worldwide. Many methods seek to ease the analytical workload required to collect, analyze, and identify these drugs. Paper spray-mass spectrometry (PS-MS) is one response to this analytical workload as it offers a rapid, affordable, and simple means for drug identification by mass spectrometry. This work centers on the use of pressure-sensitive adhesive (PSA) lined paper as a PS-MS substrate for drug recovery and detection. The use of PSA paper as a sampling and analysis substrate has been previously established but is expanded herein with new capabilities and applications. Chapter 2 introduces the combination of color tests followed by PS-MS for presumptive and confirmatory drug identification. Three color tests (cobalt thiocyanate, Simon, or Marquis) were performed on the PSA paper with subsequent drug confirmation occurring by PS-MS. Chapter 3 examines the use of PSA paper and PS-MS for the recovery and detection of fentanyl, fentanyl precursors, and analogs from shipping-related surfaces and in the presence of high amounts of cutting agents. The use of a cartridge that accommodates a full-sized PSA paper ticket was also explored for drug detection. Chapter 4 assesses PS-MS with PSA paper on portable MS instrumentation. Analyte recovery and carryover as well as instrument robustness were evaluated. The color test and PS-MS protocol examined in Chapter 2 was also successfully applied to a portable MS instrument. Application of PS-MS to the portable system highlights the potential fieldability of the technique.Item Toxicological Drug Screening using Paper Spray High-Resolution Tandem Mass Spectrometry (HR-MS/MS)(Oxford, 2018-06) McKenna, Josiah; Jett, Rachel; Shanks, Kevin; Manicke, Nicholas E.; Chemistry and Chemical Biology, School of ScienceImmunoassays and high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) are both widely used methods for drug screening in toxicology. We investigated an alternative approach for rapid drug screening: paper spray MS (PS-MS). In paper spray, the biofluid sample is spotted onto a paper substrate. Upon application of a spray solvent and an electric potential, extraction and ionization occur directly from the paper without any need for additional sample preparation. We developed two paper spray high-resolution MS/MS targeted drug screening assays using a quadrupole-orbitrap mass spectrometer, one the positive ion mode and one in the negative ion mode. In the positive ion mode, over 130 drugs and drug metabolites were semi-quantitatively screened at sub-toxic concentrations in a single 2.5 min analysis. Limits of detection and calibration performances for each target compound are reported. The PS-MS/MS assay was tested on authentic postmortem specimens, and its screening ability and semi-quantitative performance were evaluated against independent LC–MS-MS screening and confirmation assays with good agreement. The paper spray MS/MS showed good qualitative agreement with LC–MS-MS; the true positive rate of paper spray MS/MS was 92%, and the true negative rate was over 98%. The quantitative results between the two methods were also acceptable for a screening application; Passing-Bablok regression yielded a slope of 1.17 and a Pearson’s correlation coefficient of 0.996. A separate PS-MS/MS negative ion screening method was also developed for a small panel of barbiturates and structural analogs, demonstrating its potential for acidic drug detection and screening.