Development of rapid GC-MS/MS method for determination of eleven isothiocyanates and nitriles : diploma thesis

Izotiocijanati i nitrili su razgradni produkti hidrolize glukozinolata, sekundarnih metabolita biljaka iz porodice kupusnjača. Izotiocijanati pokazuju biološku aktivnost zbog čega se razvijaju analitičke metode za njihovo određivanje. U ovom diplomskom radu razvijena je brza metoda za određivanje 3- fenilpropanonitrila, 2-feniletil-izotiocijanata, izopropil-izotiocijanata, alil-izotiocijanata, benzil- izotiocijanata, fenil-izotiocijanata, 3-(metiltio)propil-izotiocijanata, 2-metoksifenil-izotiocijanata, 3- metoksifenil-izotiocijanata i 4-metoksifenil-izotiocijanata. Spregnuta tehnika plinska kromatografija- tandemska spektrometrija masa (GC-MS/MS) korištena je za odjeljivanje odabranih izotiocijanta i nitrila iz smjese te njihovo kvalitativno i kvantitativno određivanje. Za pripremu početnih otopina korišteni su komercijalno dostupni standardi navedenih izotiocijanta i nitrila te heksan kao otapalo. Spektrometar masa s trostrukim kvadrupolom, u MRM načinu snimanja, korišten je za praćenje specifičnih reakcija prijelaza (kvantitativni i dva kvalitativna za svaki analit). Spektrometrija masa optimizirana je određivanjem energija sraza s dušikom za svaku specifičnu reakciju prijelaza. Plinska kromatografija optimizirana je promjenama temperaturnog programa. Za izradu krivulja umjeravanja odabran je raspon koncentracija od 0,0005 mg/mL do 0,5 mg/mL. Ispitani parametri vrednovanja: točnost, ponovljivost, linearnost, granica dokazivanja i granica određivanja pokazali su se zadovoljavajućima te je na taj način osigurana prikladnost brzog određivanja odabranih izotiocijanata i nitrila u smjesi.Isothiocyanates and nitriles are degradation products of glucosinolate hydrolysis, secondary metabolites found in plants form cabbage family. Isothiocyanates exhibit biological activity, which is why analytical methods are being developed for their determination. In this thesis, a rapid method for the determination of 3-phenylpropanonitrile, 2-phenylethyl isothiocyanate, isopropyl isothiocyanate, allyl isothiocyanate, benzyl isothiocyanate, phenyl isothiocyanate, 3-(methylthio)propyl isothiocyanate, 2- methoxyphenyl isothiocyanate, 3-methoxyphenyl isothiocyanate, and 4-methoxyphenyl isothiocyanate was developed. A hyphenated technique gas chromatography-tandem mass spectrometry (GC-MS/MS) was employed to separate the selected isothiocyanates and nitriles from the mixture and determine them qualitatively and quantitatively. Stock solutions were prepared from commercially available standards of these compounds using hexane as solvent. A triple quadrupole mass spectrometer, operated in multiple reaction monitoring (MRM) mode, was used to monitor specific transition reactions (quantitative and two qualitative transitions for each analyte). Mass spectrometry was optimized by determining nitrogen collision energies for each specific transition reaction. Gas chromatography was optimized by changing the temperature programme. Calibration curve range from 0.0005 mg/mL to 0.5 mg/mL was selected. Evaluated validation parameters including accuracy, repeatability, linearity, limit of detection, and limit of quantification were found to be satisfactory, ensuring the suitability of the rapid determination of selected isothiocyanates and nitriles in the mixture