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Pre-screening of pesticides using straight radiation chemical ionization and Orbitrap mass spectrometry

Show simple item record 2021-06-18T08:22:46Z 2021-06-18T08:22:46Z 2021-06-18
dc.title Pre-screening of pesticides using straight radiation chemical ionization and Orbitrap mass spectrometry en
ethesis.faculty Matemaattis-luonnontieteellinen tiedekunta fi
ethesis.faculty Faculty of Science en
ethesis.faculty Matematisk-naturvetenskapliga fakulteten sv
ethesis.faculty.URI Helsingin yliopisto fi University of Helsinki en Helsingfors universitet sv
dct.creator Partovi, Fariba
dct.issued 2021
dct.language.ISO639-2 eng
dct.abstract Utilization of pesticides in the modern agriculture is often indispensable for gaining good crops. However, pesticides are abundantly being used in too hight quantities which leads to potential health risks for the consumers. Currently there are no pre-screening methods for monitoring the levels of pesticides in food, but only a negligible small percentage of all goods are being tested using the laborious standardized methods. This master’s thesis is an investigation, that was carried out in the wet laboratory of KARSA Oy Ltd, on 10 different pesticides: Glyphosate, Thiabendazole, 2-phenylphenol, Chlorpyrifos, Fludioxonil, Chlormequat, Bupirimate, Diflubenzuron, Fenpyrazamine and 2,4-dichlorophenoxyacetic acid. Pesticides were ionized using straight radiation chemical ionization (SRCI) in positive and negative modes without any added reagent and also using bromide, nitrate, acetonylacetone and acetone as reagents. Charged target molecules and adducts were detected using Thermo fisher Iontrap/Orbitrap (LTQ Orbitrap velos pro upgraded) mass spectrometer. After the initial method development and scoping measurements pesticides were studied both individually and as a mixture of all 10 pesticides. Sample solutions were first injected with syringe so that the solvent and targets evaporated at the same time inside the desorber heating block of SRCI inlet. In these syringe injection measurements, the desorber temperature was set at 150 °C. Mass range at 125–750 has been used for all the pesticides except for Chlormequat (100–750). After the syringe injection measurements, the mixture of 10 pesticides was analysed by TCM filters. Target solutions of 1 µl volume were placed on filters and after the solvents had evaporated the filters were heated from room temperature to 245°C using the same setup as with the syringe injections. In conclusion, with syringe injections 7 pesticides out of 10 were detected using positive and negative mode without any added reagent. The highest target intensities were recorded from TCM filters. Overall, applying the SRCI-Orbitrap setup for pesticide pre-screening from target solutions resulted in the detection of 9 pesticides out of 10. en
dct.subject pesticides
dct.subject atmospheric pressure chemical ionization
dct.subject Orbitrap
dct.language en
ethesis.isPublicationLicenseAccepted true
ethesis.language englanti fi
ethesis.language English en
ethesis.language engelska sv
ethesis.thesistype pro gradu -tutkielmat fi
ethesis.thesistype master's thesis en
ethesis.thesistype pro gradu-avhandlingar sv
dct.identifier.ethesis E-thesisID:c37f5315-3060-438f-811d-2235a99f787f
dct.identifier.urn URN:NBN:fi:hulib-202106183191
dc.type.dcmitype Text
ethesis.facultystudyline Mathematics / Computer and data science / Physics / Chemistry fi
ethesis.facultystudyline Mathematics / Computer and data science / Physics / Chemistry en
ethesis.facultystudyline Mathematics / Computer and data science / Physics / Chemistry sv
ethesis.mastersdegreeprogram Kemian ja molekyylitieteiden maisteriohjelma fi
ethesis.mastersdegreeprogram Master's Programme in Chemistry and Molecular Sciences en
ethesis.mastersdegreeprogram Magisterprogrammet i kemi och molekylära vetenskaper sv

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