20.500.12556/RUL-113183 Določanje neonikotinoidnih pesticidov v propolisu Analysis of neonicotinoid pesticides in propolis Namen magistrskega dela je bil razviti metodo za določevanje petih neonikotinoidnih pesticidov (acetamiprid, klotianidin, imidakloprid, tiakloprid, tiametoksam) v vzorcih propolisa. Preizkusil sem dva načina priprave vzorca: ekstrakcijo na trdno fazo (angl. SPE – Solid Phase Extraction) in QuEChERS ekstrakcijo (angl. Quick, Easy, Cheap, Effective, Rugged, Safe). Ekstrakte sem analiziral z LC-MS/MS instrumentom, ki je deloval v SRM načinu (angl. Selected Reaction Monitoring). Čistejše ekstrakte in boljše izkoristke sem dosegel z ekstrakcijo na trdno fazo, zato sem metodo SPE-HPLC-MS/MS tudi validiral. Validiral sem jo na dveh koncentracijskih nivojih (10 µg/L in 50 µg/L) s tremi ponovitvami na vsakem nivoju. Rezultati so pokazali, da daje metoda zadovoljive izkoristke (61 – 101 %) za vse analite razen za klotianidin, katerega izkoristek znaša 10 % v spodnjem in 20 % v zgornjem koncentracijskem nivoju. Ponovljivost metode je zadovoljiva, saj se relativni standardni odmiki gibljejo med 5 % in 29 % (spodnji koncentracijski nivo) ter med 3 % in 13 % (zgornji koncentracijski nivo). Za vse analite sem dosegel nizke meje zaznave (0,2 -4,4 µg/L) in meje določitve (0,8 – 14,7 µg/L). Zaradi kompleksne matrice vzorca sem za oceno matričnega efekta pripravil umeritveno premico z matričnimi raztopinami (angl. MM – Matrix Matched) in jo uporabil tudi za določitev linearnega območja in točnosti metode. Metoda je točna (relativna standardna napaka: 1,9 % – 10,4 %) ter linearna v širokem koncentracijskem območju (R2 > 0,991) za vse analite. SPE-HPLC-MS/MS metodo sem uporabil za analizo 30 realnih vzorcev propolisa (18 surovih vzorcev in 12 alkoholnih tinktur). V 7 vzorcih sem potrdil prisotnost acetamiprida, imidakloprida in tiakloprida nad mejo zaznave, vendar je bila njihova vsebnost pod mejo določitve optimizirane metode. This study aimed to develop a method for the determination of five neonicotinoid pesticides (acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam) in propolis samples. Two sample preparation methods were tested: solid-phase extraction (SPE) and quick, easy, cheap, effective, rugged, and safe (QuEChERS). The extracts were then analysed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring (SRM) mode. Because solid-phase extraction resulted in cleaner extracts and better recoveries, only the SPE-HPLC-MS/MS method was validated. The method was validated at two spiking levels (10 µg/L and 50 µg/L) in triplicate at each level. Except for clothianidin, we obtained satisfactory recoveries the other four pesticides (61 % – 101 %). Recoveries of clothianidin were 10 % at the lower and 20 % at the higher spiking level, respectively. Method repeatability was also good with a relative standard deviation from 5 % to 29 % at the lower spiking level and from 3 % to 13 % at the higher spiking level. The method also showed low limits of detection (0.2 – 4.4 µg/L) and quantification (0.8 – 14.7 µg/L). In order to compensate for the matrix effect, matrix-matched calibration was used. Based on matrix-matched calibration curves, good accuracy (relative error: 1.9 % – 10.4 %) and linearity were determined (R2 > 0.991) for all of the neonicotinoids tested. The validated SPE-HPLC-MS/MS method was used to analyse 30 propolis samples (18 raw propolis and 12 alcohol tinctures). The presence of some analytes (acetamiprid, imidacloprid and thiacloprid) were above limits of detection in 7 samples, however their conectrations were lower than limits of quantification for optimised analytical method. neonikotinoidi SPE QuEChERS propolis LC-MS/MS neonicotinoids SPE QuEChERS propolis LC-MS/MS true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2019-12-11 11:05:06 2019-12-11 11:05:09 2022-08-25 03:55:09 0000-00-00 00:00:00 2019 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 6641 1538507459 Tomsic_Rok_-_Dolocanje_neonikotinoidnih_pesticidov_v_propolisu.pdf Tomsic_Rok_-_Dolocanje_neonikotinoidnih_pesticidov_v_propolisu.pdf 1 A07A10F68DC9ECD5DBE53B1E5130827A 5ef55cdf13c2ba223f625ef6c8be1f986f2efecd4e9cefda4a8df83250bc107c 0a7f7975-a1b8-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=125223 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0