Razvoj analizne metode za določevanje izbranih onesnaževal iz materialov za stik z živili v pijačah

Žnideršič, Luka (author), Prosen, Helena (mentor)

V okviru doktorskega dela sem razvil in validiral enostavno, poceni in občutljivo metodo za direktno določanje devetih analitov iz štirih skupin spojin v pijačah. Analite sem izbral na podlagi identifikacije v predhodno izvedeni migracijski študiji na polimernih tesnilih kronskih zamaškov in verjetnosti njihove prisotnosti v realnih vzorcih kot posledice migracije iz materialov za stik z živili. Spojine sem predkoncentriral s pomočjo mikroekstrakcije na trdno fazo (SPME) in jih analiziral s plinsko kromatografijo, sklopljeno s tandemsko masno spektrometrijo (GC-MS/MS). Pri svojih raziskavah sem optimiziral naslednje SPME parametre: izbira stacionarne faze vlakna, vpliv dodatka NaCl, vpliv časa in temperature ekstrakcije ter vpliv matrice. V povezavi s slednjim sem s preprosto metodo GC-FID spremljal preostanek organskega topila v vzorcih in analiznih raztopinah. Ugotovil sem, da je z uporabo ultra inertne modifikacije stacionarne faze HP-5 kolone mogoče polarne spojine (parabene) določati brez derivatizacije, kar je ena izmed bistvenih prednosti razvite metode. Dokazal sem, da je cenovno dostopna kemikalija fenil diklorofosfat kot interni standard primerljiva in celo boljša alternativa izotopsko označenim analogom analitov. Meje zaznave metode SPME-GC-MS/MS so bile v območju 0,005 – 0,2 μg/L, relativni standardni odmiki v območju 0,8 – 5,4 % in točnost določitve za posamične analite 98 – 109 %. V steklenicah, ki sem jih zaprl s kronskimi zamaški, sem izvedel migracijsko študijo v različnih topilih in modelnih raztopinah za preverjanje migracije iz embalaže, pri kateri sem izpostavil vzorce na 50 °C za dobo šestih mesecev in dokazal prehajanje nekaterih analitov v raztopine. Izvedel sem tudi migracijsko študijo s plastičnim fermentorjem, pri kateri sem z vzorčenjem ob različnih časovnih točkah dokazal, da je prisotnost butiliranega hidroksitoluena posledica migracije s kontaktne površine posode v modelno raztopino. Analiziral sem komercialno dostopne in domače vzorce alkoholnih pijač in kisov različnih starosti, v katerih sem določil tako sledove kot tudi večje koncentracije vseh analitov, razen terc-butilhidrokinona in tris(2-butoksietil)fosfata.

• Language: Slovenian
• Keywords: materiali za stik z živili, kontaktna embalaža, migriranje spojin, SPME, GC-MS/MS, parabeni, fenolni antioksidanti, plastifikatorji
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2020
• PID: 20.500.12556/RUL-113485
• COBISS.SI-ID: 303714816
• Publication date in RUL: 10.01.2020

Secondary language

• Language: English
• Title: Development of analytical method for the determination of selected contaminants from food contact material in beverages

Abstract

In the present work, the development and validation of a simple, low-cost and sensitive method for the direct determination of nine analytes in beverages belonging to four types of compounds, is reported. The analytes were chosen based on a preliminary migration study conducted on crown cap polymer liners and on the probability of their occurence in real samples as a consequence of migration. The analytes were preconcentrated using solid-phase microextraction (SPME) and analyzed by gas chromatography – tandem mass spectrometry (GC-MS/MS). The following SPME parameters were optimized: fiber stationary phase selection, NaCl addition effect, extraction time and temperature effects, and the matrix effect. With respect to the latter, a simple GC-FID method was implemented for the monitoring of organic solvent residues in samples and analytical solutions. By using GC column with novel stationary phase (ultra inert modification of a HP-5) it is possible to analyze more polar compounds directly without a derivatization step, which is considered as one of the important advantages of the developed method. The affordable compound phenyl dichlorophosphate was proven to be not only comparable, but even a better alternative to isotopically labeled analogues as internal standards. The LODs of the SPME-GC-MS/MS method were in the range of 0.005 – 0.2 μg/L, the relative standard deviations 0.8 – 5.4 %, and the mean accuracies (recoveries) of determination 98 – 109 %. A migration study at 50 °C in a timespan of 6 months was conducted in bottles filled with various model solutions for migration testing and closed with crown caps. A migration study was also performed in a plastic fermenter where butylated hydroxytoluene was proven to migrate from the contact surface of the fermenter. Commercially available and homemade alcoholic beverages and vinegars were analyzed. Traces and larger concentrations of all the analytes with the exception of tert-butyl hydroquinone and tris(2-buthoxyethyl)phosphate were detected.

• Keywords: food contact material, contact embalage, migration of compounds, SPME, GC-MS/MS, parabens, phenolic antioxidants, plasticizers