UNIVERSITY OF LATVIA FACULTY OF CHEMISTRY APPLICATION OF HIGH RESOLUTION MASS SPECTROMETRY AND MULTI-ENZYMATIC BIOSENSORS FOR NON-TARGETED SCREENING OF CHEMICAL ENVIRONMENTAL AND FOOD CONTAMINANTS DOCTORAL THESIS AUGSTAS IZŠĶIRTSPĒJAS MASSPEKTROMETRIJAS UN MULTI- ENZIMĀTISKU BIOSENSORU PIELIETOJUMS ĶĪMISKO VIDES UN PĀRTIKAS PIESĀRŅOTĀJU NEMĒRĶĒTAM (NON-TARGETED) SKRĪNINGAM PROMOCIJAS DARBS JĀNIS RUŠKO Scientific supervisors: Prof., Dr. chem. Vadims Bartkevičs Prof., Dr. chem. Arturs Vīksna Rīga 2021 The doctoral thesis was carried out at the Institute of Food Safety, Animal Health and Environment “BIOR” from 2017 to 2020 and National Research Council of Italy – Institute of Protein Biochemistry from 2017 to 2018. The thesis contains the introduction, 3 chapters, conclusions, reference list, 9 annexes. Form of the thesis: dissertation in chemistry, analytical chemistry. Supervisors: Prof., Dr. chem. Vadims Bartkevičs Prof., Dr. chem. Arturs Vīksna Reviewers: 1) Prof., Dr. habil. chem. Māris Kļaviņš, University of Latvia; 2) Dr. Kristaps Kļaviņš, Riga Technical University; 3) Prof., Habil. Dr. Arunas Ramanavicius, Vilnius University, Lithuania. The thesis will be defended at the public session of the Doctoral Committee of Chemistry, University of Latvia, at the Faculty of Chemistry of the University of Latvia (Jelgavas Str. 1, Riga, Latvia) on June 18th, 2021 at 14:00. The thesis is available at the Library of the University of Latvia, Raiņa Blvd. 19, Riga, Latvia. Chairman of the Doctoral Committee _______________/ Prof., Dr. chem. Edgars Sūna/ Secretary of the Doctoral Committee _______________/ Dr. chem. Vita Rudoviča/ © University of Latvia, 2021 © Janis Rusko, 2021 1 CONTENTS ABSTRACT .................................................................................................................................... 7 ANOTĀCIJA ................................................................................................................................... 8 INTRODUCTION ........................................................................................................................... 9 1. LITERATURE REVIEW ..................................................................................................... 14 1.1. Principles of non-target methodologies ..................................................................... 14 1.1.1. Sample preparation methods .......................................................................... 15 1.1.2. Instrumental analysis methods ....................................................................... 16 1.1.3. Building blocks of non-target analysis........................................................... 17 1.2. Compound identification in non-target mass spectrometry ....................................... 20 1.2.1. Confidence and bias in identification ............................................................. 20 1.2.2. Identification via mass spectra ....................................................................... 23 1.3. Biosensors .................................................................................................................. 24 1.3.1. Biochemical strategies for the chemical detection ......................................... 24 1.3.2. Principle of enzymatic biosensors .................................................................. 26 1.3.3. Detection of neurotoxic chemicals ................................................................. 27 2. EXPERIMENTAL PART .................................................................................................... 28 2.1. Targeted suspect methodology – determination of anticoccidials ............................. 28 2.1.1. Chemicals and materials ................................................................................ 28 2.1.2. Samples and sample preparation .................................................................... 28 2.1.3. Parameters of UHPLC-HRMS method .......................................................... 29 2.1.4. Method optimization workflow ..................................................................... 30 2.1.5. Method validation .......................................................................................... 33 2.2. Non-target methodology - food contact materials ..................................................... 34 2.2.1. Sampling and sample preparation .................................................................. 34 2.2.2. Databases used as basis for suspect screening ............................................... 35 2.2.3. Parameters of UHPLC-HRMS method .......................................................... 37 2.2.4. Data processing and compound identification ............................................... 38 2.2.5. Toxicological endpoint screening .................................................................. 40 2.3. Biosensors .................................................................................................................. 41 2.3.1. Reagents ......................................................................................................... 41 2.3.2. MU standard calibration curve in HEPES ..................................................... 41 2.3.3. Enzyme purification ....................................................................................... 42 2.3.4. Fluorescence standard enzymatic assay ......................................................... 42 2 2.3.5. Kinetic constants ............................................................................................ 42 2.3.6. Inhibition Assay of EST2 in Presence of Pesticides ...................................... 43 2.3.7. Docking analysis ............................................................................................ 43 2.3.8. Phosphorothionate pesticide oxidation by NBS............................................. 44 2.3.9. MS analysis of NBS-oxidized pesticides ....................................................... 44 2.3.10. Determination of EST2 activity in presence of NBS ................................... 45 2.3.11. EST2 assay on robotic workstation and OP screening ................................ 45 2.3.12. Collection of human urine and blood samples ............................................. 47 2.3.13. EST2 residual activity in human urine ......................................................... 47 2.3.14. Paraoxon inhibition assay of EST2 in human urine ..................................... 47 3. RESULTS AND DISCUSSION .......................................................................................... 48 3.1. Targeted suspect methodology – determination of anticoccidials ............................. 48 3.1.1. Sample extraction ........................................................................................... 48 3.1.2. Liquid chromatography .................................................................................. 48 3.1.3. MS conditions ................................................................................................ 48 3.1.4. Optimization of MS parameters ..................................................................... 49 3.1.5. Analytical method validation ......................................................................... 60 3.1.6. Method applicability ...................................................................................... 62 3.2. Non-target methodology application for a case study of food contact materials ...... 62 3.2.1. Data acquisition and processing ..................................................................... 62 3.2.2. Identification of migrating compounds - method performance ..................... 64 3.2.3. Leaching of the materials ............................................................................... 66 3.2.4. Characteristics of the identified substances ................................................... 70 3.2.5. Hazard identification and risk prioritization .................................................. 71 3.2.6. General remarks regarding the analysis of paper food contact materials ...... 74 3.3. Determination of organophosphate suspects by biosensors ...................................... 75 3.3.1. A robotic system for an automated biosensor analysis .................................. 75 3.3.2. Determination of organophosphates in urine ................................................. 83 CONCLUSIONS ........................................................................................................................... 90 ACKNOWLEDGEMENTS........................................................................................................... 92 REFERENCES .............................................................................................................................. 93 ANNEXES................................................................................................................................... 105 3 ABBREVIATIONS 4-MU or MU 4-Methylumberlliferone 4-MUBu 4-Methylumbelliferyl butyrate AChE Acetylcholinesterase AGC Automatic gain control AIF All ion fragmentation method ANOVA Analysis of variance APL Amprolium Arb. or a.u. Arbitrary units BBD Box-Behnken response surface design model BChE Butyrylcholinesterase CASRN or CAS Chemical abstracts service registry number CIR Chemical Identifier resolver KNIME extention CLOP Clopidol COC Chemicals of concern DCZ Diclazuril DEC Decoquinate DMSO Dimethyl sulfoxide DNC Nicarbazin EC European Commission EFSA European Food