Valentina Pirro (Presenter)
Purdue University
Bio: Valentina Pirro received her Ph.D. in Science and High Technology from the University of Turin, Italy. She is currently a postdoctoral researcher in Chemistry at Purdue University, under the supervision of Prof. Robert Graham Cooks. Her current research interest includes the application of cutting-edge mass spectrometric techniques, like ambient mass spectrometry and imaging mass spectrometry, in the field of clinical and forensic toxicology.
Authorship: Valentina Pirro, Alan K. Jarmusch and R. Graham Cooks
Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN 47907
| Short Abstract Touch spray (TS) with medical swabs was recently developed as an ambient ionization technique for direct oral fluid analysis in point-of-care clinical-toxicological applications. We present recent advances to this methodology for the detection of over 20 common drugs and pharmaceuticals in oral fluid. Fundamental aspects of ionization were explored including swab tip material and geometry, solvent flow rate, etc. Electric field simulations and recorded video of the ionization process allow further understanding of the ionization phenomenon. In addition to the detection of common drugs via targeted MSn, a data-independent MS/MS strategy using TS is presented as drug screening methodology. |
Long Abstract
Touch spray - mass spectrometry (TS-MS) is a spray-based ambient ionization technique in which a sample is transferred onto a probe from which direct ionization occurs via electrospray-like mechanisms. The usage of a medical swab as a probe allows for direct, non-invasive (and potentially in vivo) oral fluid testing, particularly in point-of-care clinical and toxicological applications. We present recent advances to this methodology and the detection of over 20 common drugs of abuse and pharmaceuticals (e.g. cocaine, opiates and opioids, amphetamines, synthetic cathinones, benzodiazepines) in neat oral fluid.
Drug containing oral fluid was analyzed with acetonitrile doped with formic acid (0.1%) and detected using targeted MSn using a benchtop linear ion trap mass spectrometer. Swabs were spiked with oral fluid, allowed to dry for a few minutes, and then affixed in front of the MS inlet for MS analysis. Analysis takes place as follows: the solvent was applied to the swab tip; high voltage was applied directly to the swab handle (e.g. aluminum alloy). We tested the analytical selectivity and specificity, matrix effect, analyte retention, and drug recovery from the swabs. Furthermore, a data-independent MS/MS strategy using TS was developed as a screening methodology for unknowns, and tested through participation in a laboratory proficiency test (LGC Standards). Analysis time is rapid and requires minute amounts of oral fluid (about 25 µL), with detection limits in the ng/mL range. Fundamental aspects of ionization were also explored including swab tip material and geometry, solvent flow rate, voltage applied, etc. Electric field simulations and recorded videos of the ionization process allowed further understanding of the ionization phenomenon.
Current performance is limited based primarily on the manufacturing tolerance of medical swabs, and requires refinement (as well as the analytical procedures) to meet clinical/legal requirements for drug testing in oral fluid. However, these initial experimental results demonstrate that TS-MS methodology is sensitive and specific for screening applications. The current use of swabs that are commercially available and are approved as medical devices can facilitate the adoption of TS-MS in point-of-care testing, even though significant improvements in analytical performances can be achieved by designing a swab for MS analysis (fit-for-function).
References & Acknowledgements:
| Description | Y/N | Source |
| Grants | no | |
| Salary | no | |
| Board Member | no | |
| Stock | no | |
| Expenses | no |
IP Royalty: no
| Planning to mention or discuss specific products or technology of the company(ies) listed above: | no |