MSACL 2024 Abstract

The Potential of Paper Spray-Mass Spectrometry for the Analysis of NPS in the Emergency Department

Stefania Boccuzzi (1), David Cowan (1), Paul Dargan (2,3) Edward Goucher (4), Sarvesh Iyer (4), Vincenzo Abbate (1)
(1) Department of Analytical, Environmental and Forensic Sciences, King's College London, London, UK (2) Clinical Toxicology, Faculty of Life Sciences and Medicine, King's College London, London, UK (3) Clinical Toxicology, Guy's and St Thomas' NHS Foundation Trust and King's Health Partners, London, UK (4) Thermo Fisher Scientific, San Jose, CA

Ed Goucher, PhD (Presenter) Thermo Fisher Scientific

Relevant Financial Disclosures (within past 24 months, reported on Sep 12, 2021) No relevant financial relationship(s) to disclose. Conflict mitigation NOT REQUIRED.

INTRODUCTION: Ambient ionization has recently become an attractive addition to toxicology workflows, as it provides rapid analysis of drugs of abuse compared with traditional chromatographic techniques such as LC-MS. Based on electrospray ionization mechanisms, paper spray ionization (PSI) generates ions directly from a sample spotted onto a paper substrate, minimizing the cost and time of analysis. PSI uses dried matrix spots (DMS), a well-established but evolving trend in toxicology providing an alternative to collection of venous blood samples. Using DMS and PSI combined introduces the possibility of less invasive sample collection for the patient, no sample extraction or chromatography required facilitating lower cost per analysis, and a quicker turnaround of results.

Emergency department (ED) presentations due to acute drug toxicity can be life-threatening; currently clinicians rely on self-report and clinical patterns of toxicity to determine the drug(s) likely to be involved. The use of a VeriSpray™ Paper Spray Ion Source coupled to a mass spectrometer for identification and quantitation of drugs of abuse can provide results on drugs present to inform patient care early in the patients’ ED presentation. As such, there is the potential for a wide-reaching benefit to ED care, ultimately enabling clinicians to tailor patient care based on analytically confirmed drug use.

METHODS: Initial investigations have focused on the development and validation of synthetic cathinones in human urine. A synthetic cathinone working solution containing 4-CEC, 4-Cl-α-PPP, 4-Cl-α-PVP, MDPV, 4-EMC, N-ethylhexedrone, and MDPV-d8 was spiked into urine at an appropriate concentration and vortexed. The sample was spotted onto a VeriSpray™ sample plate containing Whatman™ ET 31 chromatography paper in a triangular shape and allowed to dry at room temperature. Results were acquired in less than 2.5 minutes per sample and validated according to ANSI/ASB 036 guidelines.

RESULTS: Method development focused on improving the signal to noise ratios and ion ratios per analyte to offset any interference from the paper substrate and increase the selectivity of subsequent quantitative results. By targeting less abundant ion transitions, up to a 30-fold increase in the signal to noise was seen, complemented by a significant decrease in the interference from the paper substrate and urine itself. Subsequent preliminary method validation demonstrated R2 > 0.98 and no carryover. Accuracy and precision values were between -3 % and 4 % and 16 % and 17 % respectively, despite high matrix effects and no sample extraction being carried out.

CONCLUSION: The increased signal to noise ratios and initial method validation provides an encouraging starting point for future standard operating procedures when using the VeriSpray™ Paper Spray Ion Source in a research and clinical setting. By demonstrating quantifiable results without the need for extensive sample preparation, the continued optimization for a wider panel of drugs of abuse as the study progresses will inform current and future applications to achieve the long-term aim of using a VeriSpray™ Paper Spray Ion Source in the ED.