Thermal Desorption Multi-Scheme Chemical Ionization Orbitrap Mass Spectrometry for Pesticide Residue Screening
Partovi, Fariba (2026)
Omakustanne / Self-published
2026
Tekniikan ja luonnontieteiden tohtoriohjelma - Doctoral Programme in Engineering and Natural Sciences
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Väitöspäivä
2026-06-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-03-4656-0
https://urn.fi/URN:ISBN:978-952-03-4656-0
Tiivistelmä
The increasing scale and chemical diversity of pesticide use demand analytical approaches capable of rapid and comprehensive residue screening. Conventional chromatographic methods provide high accuracy but are limited by time-intensive sample preparation and low throughput. This dissertation develops and evaluates thermal desorption multi-scheme chemical ionization Orbitrap mass spectrometry (TD-MION-OMS) as a fast, high-throughput screening platform.
The approach integrates multiple reagent-ion chemistries within a single system to enhance detection coverage across structurally diverse pesticides. Analysis of large multicomponent libraries (up to 651 pesticides) demonstrated that no single ionization scheme provides comprehensive coverage, whereas combining complementary ionization mechanisms significantly improves performance. Detection of up to 69% of compounds at 100 ng mL⁻¹ was achieved, with coverage retained at lower concentrations relevant to regulatory limits.
Quantum-chemical calculations provided molecular-level insight into ionization mechanisms, showing that bromide-mode sensitivity is linked to cluster stability, while protonated acetone promotes efficient proton-transfer ionization. Uronium was found to enable strong analyte binding and selective ionization pathways.
The platform was successfully applied to fruit extracts and minimally prepared samples, enabling rapid pesticide detection with reduced or no sample preparation. TD-MION-OMS is thus established as a complementary pre-screening tool, offering a practical pathway toward faster and more efficient pesticide monitoring workflows.
The approach integrates multiple reagent-ion chemistries within a single system to enhance detection coverage across structurally diverse pesticides. Analysis of large multicomponent libraries (up to 651 pesticides) demonstrated that no single ionization scheme provides comprehensive coverage, whereas combining complementary ionization mechanisms significantly improves performance. Detection of up to 69% of compounds at 100 ng mL⁻¹ was achieved, with coverage retained at lower concentrations relevant to regulatory limits.
Quantum-chemical calculations provided molecular-level insight into ionization mechanisms, showing that bromide-mode sensitivity is linked to cluster stability, while protonated acetone promotes efficient proton-transfer ionization. Uronium was found to enable strong analyte binding and selective ionization pathways.
The platform was successfully applied to fruit extracts and minimally prepared samples, enabling rapid pesticide detection with reduced or no sample preparation. TD-MION-OMS is thus established as a complementary pre-screening tool, offering a practical pathway toward faster and more efficient pesticide monitoring workflows.
Kokoelmat
- Väitöskirjat [5321]