Desorption electrospray ionization mass spectrometry (DESI-MS) - applications in chemical reaction acceleration and coupling with paper-based analytical devices (µPADS)

• Grant number: 25/04694-4
• Support Opportunities: Scholarships abroad - Research
• Start date: August 20, 2025
• End date: August 19, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Evandro Piccin
• Grantee: Evandro Piccin
• Host Investigator: Robert Graham Cooks
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Purdue University, United States

Abstract

This project presents research development proposals involving the desorption electrospray ionization mass spectrometry (DESI-MS) technique, specifically in three general areas: (i) acceleration of chemical reactions in microdroplets aimed at the derivatization of specific functional groups, (ii) combination with paper-based analytical devices (µPADs) with electrochemical detection, and (iii) development of µPADs with multiple detection modes (colorimetry / electrochemistry / DESI-MS) for the analysis of forensic compounds. In line (i) of the project, the objective is to evaluate new derivatization reagents to improve the ionization of molecules that are not easily ionized by DESI, such as aldehydes, ethers, alcohols, lipids, steroids, ketones, olefins, among others.The combination of DESI with paper-based analytical devices (µPADs) with electrochemical detection (EC), which will be explored in the line (ii) of this project, the intention is to obtain an analytical tool for studying redox reaction mechanisms and identifying reaction products and intermediates. EC transformations can also be used to enhance ionization efficiency and derivatize analytes before MS, improving sensitivity and chemical specificity. This project aims to investigate the possibility of improving existing interfaces in terms of simplicity, reproducibility, response time, and cost.Regarding line (iii), the objective is to develop a µPAD with multiple detection modes (colorimetry, electrochemistry, and mass spectrometry) on the same paper platform for the forensic analysis of drugs of abuse. Forensic analysis will be emphasized, as they require analyses using at least two distinct techniques, one of which must be spectroscopic. Thus, preliminary screening analyses can be performed on-site, at the seizure location, using the electrochemical and colorimetric detections of the µPAD. Subsequently, DESI-MS analysis will enable unequivocal identification of the drug in question.