1. Določanje in kemometrijska analiza organskih spojinadsorbiranih na prašne delce PM10Alen Miuc, 2017, doktorska disertacija Opis: Namen naše raziskave je bil določanje okolju nevarnih organskih spojin adsorbiranih na prašne delce PM10. Vzorce smo odvzeli v skladu s standardom SIST EN 12341:2014. Po gravimetrijskem določanju delcev PM10 smo vzorce uporabili še za določitev kemične sestave in preučitev pomembnih sezonskih razlik v sestavi organskih snovi, ki jih vsebujejo delci PM10. V ta namen smo razvili analizno metodo za določevanje organskih spojin v ekstraktih vzorcev prašnih delcev PM10 s plinsko kromatografijo in masno spektrometrijo. S pomočjo kemometrijskih metod smo določili pomembne sezonske in lokacijske razlike sestave organskih spojin v zraku nad Mariborom. Določali smo sestavo spojin, ki označujejo onesnaženost in ugotavljali, katere spojine so antropogenega izvora. Ugotavljali smo, kako se sestava razlikuje glede na letni čas in odvzemno mesto vzorčenja.
PM10 je frakcija respirabilnih prašnih delcev s premerom 10 μm ali manj. Suspendirani delci v zraku so naravnega (gozd, cvetni prah, padavine, neurja, vegetacija, vulkanski pepel...) ali antropogenega izvora (emisije industrije, prometa, sežig fosilnih goriv, biomase, kmetijstvo). Glede na izvor delce razdelimo na primarne in sekundarne. Primarni delci se sproščajo v ozračje direktno. Velik del organskih aerosolov v atmosferi je mogoče pripisati sekundarnim organskim aerosolom (SOA), ki nastajajo pri oksidaciji hlapnih organskih spojin (VOC) z atmosferskimi oksidanti kot so O3, OH• radikali in NO3• radikali. Fotokemični procesi vplivajo na kemično sestavo organskih spojin in njihove fizikalno-kemijske lastnosti kot so hlapnost, higroskopičnost ali kondenzacijsko aktivnost SOA spojin.
Zakonsko predpisana 24-urna mejna koncentracija za delce PM10 je 50 μg/m3. Preseganja dnevnih mejnih vrednosti PM10 so praviloma v zimskem letnem času. Povišana raven delcev PM10 je predvsem posledica lokalnih izpustov. Dve tretjini vseh izpustov delcev PM10 v Sloveniji je posledica kurjenja lesa gospodinjstev.
Raziskovalno delo zaznave in določanja spojin organskih onesnaževal vključuje 120 standardno odvzetih vzorcev prašnih delcev (standard SIST EN 12341:2014) z uporabo nizko volumskega vzorčevalnika, ter analitsko določevanje s plinsko kromatografijo in masno spektrometrijo (GC/MS). Za določanje polarnih organskih spojin smo uporabili sililiranje kot kemijsko tehniko derivatizacije.
Nabor organskih spojin v ekstraktih prašnih delcev PM10 vključuje maščobne kisline, n- in izo-alkane, ftalatne estre, siloksane, sterole, sladkorje, sladkorne alkohole, dikarboksilne kisline, spojine razgradnje lignina in lesnih smol, policiklične organske ogljikovodike, organske dušikove spojine ter produkte sekundarne oksidacije monoterpenskih spojin. S pomočjo kemijske karakterizacije smo določili sezonske in lokacijske razlike merilnih mest. Za proučevanje smo uporabili kemometrijske metode kot so korelacijska analiza, metoda glavnih osi, hierarhično razvrščanje, analiza variance (ANOVA).
V toplejših letnih časih prevladujejo na prašnih delcih adsorbirane biogene spojine nad antropogenimi spojinami. Pozimi prevladujejo antropogene organske spojine. Najbolj reprezentativne spojine zimskih vzorcev zraka so: levoglukozan, manozan, spojine ftalatnih estrov, spojine razgradnje ligninov in palmitinska kislina. Poleti prevladujejo derivati sladkorjev in sladkornih alkoholov. Na razlike vzorcev glede na sestavo organskih spojin najbolj vplivajo spojine PAHov, 1,3,5-trifenilbenzen, pinonska kislina, DEHP, glicin, nonanojska kislina (C9:0), ter jabolčna kislina in adipinska kislina.
V številnih vzorcih je bil prisoten razpotegnjen kromatografski vrh neločene kompleksne mešanice (NKM), ki se razlikuje glede na letni čas in sestavo. Izvor NKM pozimi pripisujemo kurjenju fosilnih goriv ter izpuhov motornih vozil, poleti pa fotooksidacijskim procesom monoterpenov.
Do lokacijskih razlik v sestavi organskih spojin adsorbiranih na ekstraktih vzorcev PM10 prihaja zaradi različnih antropogenih in biogenih izpustov, obremenjenosti posamezne
Ključne besede: PM10, EN 12341, prašni delci, organske spojine, GC/MS.
Objavljeno v DKUM: 08.11.2017; Ogledov: 2025; Prenosov: 195
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2. Composition of organic compounds adsorbed on PM10 in the air above MariborAlen Miuc, Ernest Vončina, Uroš Lešnik, 2015, izvirni znanstveni članek Opis: Organic compounds in atmospheric particulate matter above Maribor were analysed in 120 samples of PM10 sampled according to the EN 12341:2014 reference method. Organic compounds compositions were investigated together with the primary and secondary sources of air pollution. Silylation as derivatisation method was used for the GC-MS determination of volatile and semi-volatile polar organic compounds. Distribution of fatty acids, n-alkanes and iso-alkanes, phthalate esters, siloxanes, different sterols, various sugars and sugar alcohols, compounds of lignin and resin acids, dicarboxylic acids from photochemical reactions, PAHs, organic nitrogen compounds and products from secondary oxi- dation of monoterpenes were determined. The use of silicone grease for the purpose of lubricating the impact surface of the air sampler caused higher values of gravimetric determination. Solid particles may have been bounced from the surface of a greasy impact plate and re-entrained within the air stream and then collected on a sample filter. The carryover of siloxanes was at least from 5% up to 15% of the accumulated particles weight, depending on ambient temperature. This was the reason that the gravimetric results for determination of PM10 according to the standard EN 12341:2014 were overestimated.
Ključne besede: secondary organic aerosol, volatile organic compounds, PM10, EN 1234:2014
Objavljeno v DKUM: 17.08.2017; Ogledov: 1882; Prenosov: 339
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3. Chemometric characterisation of the quality of ground waters from different wells in SloveniaErnest Vončina, Darinka Brodnjak-Vončina, Nataša Sovič, Marjana Novič, 2007, izvirni znanstveni članek Opis: The quality of ground water as a source of drinking water in Slovenia is regularly monitored. One of the monitoring programmes is performed on 5 wells for drinking water supply, 3 industrial wells and 2 ground water monitoring wells. Two hundred and fourteen samples of ground waters were analysed in the time 2003-2004. Samples were gathered from ten different sampling sites and physical chemical measurements were performed. The following 13 physical chemical parameters were regularly controlled: temperature, pH, conductivity, nitrate, AOX (adsorbable organic halogens), metals such as chromium, pesticides (desethyl atrazine, atrazine and 2,6-dichlorobenzamide), highly-volatile halogenated hydrocarbons (trichlorometane, 1,1,2,2-tetrachloroethene and 1,1,2-trichloroethene). For handling the results different chemometrics methods were employed, such as basic statistical methods for the determination of mean and median values, standard deviations, minimal and maximal values of measured parameters and their mutual correlation coefficients, cluster analysis (CA), the principal component analysis (PCA), the clustering method based on Kohonen neural network, and linear discriminant analysis (LDA). The study gives the opportunity to follow the quality of ground waters at different sampling sites within the defined time period. Monitoring of general pollution of ground waters and following measuring can be used to search the pollution source, to plan prevention measures and to protect from pollution, as well.
Ključne besede: ground waters, water quality, principal component analysis, classification, Kohonen neural networks
Objavljeno v DKUM: 21.12.2015; Ogledov: 2145; Prenosov: 152
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4. Simultaneous determination of phthalates, their metabolites, alkylphenols and bisphenol a using GC-MS in urine of men with fertility problemsRoman Kranvogl, Jure Knez, Alen Miuc, Ernest Vončina, Darinka Brodnjak-Vončina, Veljko Vlaisavljević, 2014, izvirni znanstveni članek Opis: A GC-MS method was successfully applied to measure simultaneously the concentrations of endocrine disrupting compounds (5 dialkyl phthalates, 9 phthalate monoesters, 3 alkylphenols and bisphenol A) in 136 male urine samples. In the present study the method was validated and concentrations of EDCs were determined. The results were compared with results from other studies. Correlations between endocrine disrupting compounds and also correlations of endocrine disrupting compounds with two semen quality parameters are presented and evaluated. Significant positive correlations were found between almost all the endocrine disrupting compounds. The parameter sum of DEHP (SUM DEHP) was positively correlated to all the endocrine disrupting compounds but negatively to two semen quality parameters. Negative correlations between the endocrine disrupting compounds and the semen quality parameters could indicate that endocrine disrupting compounds could cause reproductive problems by decreasing the semen count and quality. This research will have helped to evaluate human exposure to endocrine disrupting compounds.
Ključne besede: endocrine disrupting compounds, fertility, fertility, phthalates, bisphenol A, alkylphenols, human urine
Objavljeno v DKUM: 21.12.2015; Ogledov: 1937; Prenosov: 175
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5. Determination of major phenolic acids, phenolic diterpenes and triterpenes in Rosemary (Rosmarinus Officinalis L.) by gas chromatography and mass spectrometryMaša Islamčević Razboršek, Darinka Brodnjak-Vončina, Valter Doleček, Ernest Vončina, 2007, izvirni znanstveni članek Opis: A gas chromatographic-mass spectrometric (GC-MS) method for the simultaneous identification and quantification of seven major phenolic and terpenic compounds in Rosmarinus officinalis L. was developed. The compounds were identified as trimethylsilyl (TMS) derivatives of phenolic acids (caffeic and rosmarinic acid), phenolic diterpene (carnosic acid), and pentacyclic triterpenes (ursolic, oleanolic, betulinic acid and betulin). These compounds have been identified by retention time and comparison of mass spectra. The procedure involves ultrasonic extraction using solvent mixture of tetrahydrofuran and ethanol. Extracts were fractionated by size exclusion chromatography (SEC) after purifying on graphitised carbon. The fraction with phenolic and terpenic compounds was derivatised prior to GC-MS analysis using N-methyl-N-trimethylsilyl trifluoroacetamide (MSTFA) as a derivatisation reagent. The derivatisation process was optimized regarding temperature and reaction time. The linearity of the method was tested in concentration range 4-25 mg L$^{–1}$. The correlation coefficients ($r^2$) were in the range of 0.997 to 0.999. The average recoveries for all compounds ranged from 80 to 82%. The GC-MS technique is specific and sensitive, and can be used for simultaneous identification and determination of a wide range of phenolic and terpenic compounds in different plants even at trace levels.
Ključne besede: Rosmarinus officinalis, diterpenes, triterpenes, size exclusion chromatography, gas chromatography, mass spectrometry
Objavljeno v DKUM: 21.12.2015; Ogledov: 1915; Prenosov: 216
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6. Presence of dioxins in textile dyes and their fate during the dyeing processBoštjan Križanec, Alenka Majcen Le Marechal, Ernest Vončina, Darinka Brodnjak-Vončina, 2005, izvirni znanstveni članek Opis: Considerable levels of highly toxic polychlorinated dibenzo-p-dioxins (PCCDs) and polychlorinated dibenzofurans (PCDFs) were determined in two among the sixanalysed disperse textile dyes. The dioxin homologue profile of these dyes was similar to that found in some environmental and industrial samples, connected with the textile industry. Dyes contaminated with dioxins were further used in industrial polyester dyeing processes at laboratory scale. We observed the changes in dioxin contents, dioxin transformations and their distribution during the textile dyeing process. After the dyeing and textile finishing processes the content of dioxins was up to fifteen times higher. More than 85% of the total dioxin content was found in dyed polyester. Other 15% was discharged with waste dye bath. Our results confirmed that the presence of dioxins in some textile dyes may be a significant source regardinghuman exposure and environmental contamination.
Ključne besede: textile dyeing, textile dyes, dioxins, furans, formation, polychlorinated dibenzofurans, polychlorinated dibenzo-p-dioxins
Objavljeno v DKUM: 10.07.2015; Ogledov: 1516; Prenosov: 121
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7. Naprava za pripravo referenčnega materiala za raztopljene pline v transformatorskih oljih : zaključno poročilo EUREKA projekta IRMDGA, št. E!6779Darinka Brodnjak-Vončina, Jasmina Korenak, Irena Petrinić, Maša Islamčević Razboršek, Aljana Petek, Jože Golič, Matjaž Golič, Peter Mlinarič, Ernest Vončina, Alen Miuc, Ladislav Küčan, 2014, končno poročilo o rezultatih raziskav Opis:
Ključne besede: araztopljeni plini, transformatorska olja
Objavljeno v DKUM: 18.11.2014; Ogledov: 1902; Prenosov: 108
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8. DOLOČEVANJE ENDOKRINIH MOTILCEV V URINU Z GC/MS IN KEMOMETRIJSKA KARAKTERIZACIJARoman Kranvogl, 2014, doktorska disertacija Opis: V doktorski nalogi smo proučevali vpliv nekaterih spojin okoljskih endokrinih motilcev na plodnost moških z namenom, da bi preverili hipotezo ali vplivajo endokrini motilci na kakovost semenčic. V študijo smo vključili 136 parov, ki so se zdravili zaradi neplodnosti.
Za analitiko sledov spojin endokrinih motilcev v urinu smo razvili analizno metodo določevanja s plinsko kromatografijo in masno spektrometrijo. Uporabili smo 13C izotopsko označene standardne spojine. Po dodatku internih standardov smo za dekonjugacijo analitov urinu dodali encim β-glukuronidazo. Vzorec smo nato nakisali s HCl na pH 2. Sledila je ekstrakcija z diklorometanom. Čiščenje ekstraktov smo izvedli na SiO2 koloni ter tako odstranili bazične interference, ki jih predstavljajo aminokisline, sečnina, amini in druge bazične spojine. Očiščeni ekstrakt smo odparili do suhega in dodali derivatizacijski reagent N-metil-N-trimetilsilil trifluoroacetamid (MSTFA). Sililirani ekstrakt smo analizirali s plinsko kromatografijo in masno spektrometrijo. Uporabljena je bila tehnika snemanja izbranih masnih fragmentov (SIM).
Sočasno smo določali di-alkil ftalate: di-metil ftalat (DMP), di-etil ftalat (DEP), di-butil ftalat (DBP), benzil-butil ftalat (BzBP) ter di-(2-etil-heksil) ftalat (DEHP), njihove metabolite mono-alkil ftalate: mono-etil ftalat (MEP), mono-izo-butil ftalat (MiBP), mono-n-butil ftalat (MnBP), mono-(2-etilheksil) ftalat (MEHP), mono-benzil ftalat (MBzP), mono-izo-nonil ftalat (MiNP), mono-n-oktil ftalat (MnOP), mono-(2-etil-5-oksoheksil)ftalat (MEOHP) ter mono-(2-etil-5-hidroksiheksil)ftalat (MEHHP). Določali smo alkilfenole: 4-terc-oktilfenol (4-tOP), 4-n-oktilfenol (4nOP) ter 4-n-nonilfenol (4nNP). Prav tako smo določali bisfenol A (BPA).
Izvedli smo validacijo metode. Meja določanja je bila za bisfenol A 0,1 µg L-1, za mono-alkil ftalate in alkilfenole 1 µg L-1, in za di-alkil ftalate 5 µg L-1. Linearnost metode smo preverili v koncentracijskem območju od 1 do 200 µg L-1. Uporabljena metoda se je pri kvantitativnem določanju spojin endokrinih motilcev v vzorcih urinov izkazala za uspešno, saj je natančna, točna in selektivna. Omogoča sočasno določanje endokrinih spojin z nizko mejo zaznavnosti v območju µg L-1. Z uporabo tehnike snemanja celotnega masnega spektra smo določili še 60 drugih spojin v urinu (maščobne kisline, steroide, mono-aromatske spojine in druge spojine).
Kemometrijsko karakterizacijo smo izvedli s pomočjo podatkov pridobljenih z analizami 136 vzorcev urinov moških, ki imajo težave s plodnostjo. Namen raziskave je bil ugotoviti ali obstajajo pomembne razlike med vzorci, ki smo jih uvrstili v dve skupini, glede na normalno ter zmanjšano kakovost semenčic. Skupini se razlikujeta po vrednostih koncentracije in gibljivosti semenčic. Cilj kemometrijske karakterizacije je bil poiskati korelacije med vsebnostjo spojin endokrinih motilcev v urinu, kot so ftalatni estri in njihovi metaboliti, oktil in nonil alkilfenoli in bisfenol A ter kliničnimi parametri kakovosti semenčic kot sta koncentracija in gibljivost semenčic. Dodatno smo iskali korelacije med kakovostjo semenčic in vsebnostjo hormonov: FSH (folikel-stimulativni hormon), LH (luteinizarajoči hormon), estrogen, testosteron, SHBG (spolne hormone vezoči globulin), inhibinB.
Izvedli smo korelacijsko analizo, analizo variance (ANOVA), Mann Whitney test, analizo glavnih osi (PCA), hierarhično razvrščanje (CA), linearno diskriminatno analizo (LDA), metodo gradnje regresijskih dreves (CART) in umetne nevronske mreže (ANN).
Študija je pokazala, da obstajajo pomembne razlike med obema skupinama moških, ki imajo težave s plodnostjo, predvsem glede na vsebnost di-(2-etilheksil) ftalata (DEHP), mono-(2-etilheksil) ftalata (MEHP) in obeh sekundarnih metabolitov mono-(2-etil-5-oksoheksil) ftalata (MEOHP) ter mono-(2-etil-5-hidroksiheksil) ftalata (MEHHP). V vzorcih urina moških z zmanjšano kakovostjo semenčic so bile izmerjene vsebnosti endokrinih motilcev v povprečju dvakrat višje od vsebnosti v vzorcih urina moških
Ključne besede: Ftalati, metaboliti ftalatov, alkilfenoli, bisfenol A, plinska kromatografija, masna spektrometrija, urin, kemometrija.
Objavljeno v DKUM: 11.07.2014; Ogledov: 3499; Prenosov: 548
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9. Analitika nevarnih snovi v okolju : zapiski predavanjErnest Vončina, 2013, drugo učno gradivo Ključne besede: analizna kemija, dioksini, furani, poliklorirani dibenzo-p-dioksini, poliklorirani bifenili, organske kositrove spojine, pesticidi, nonilfenoli, N-nitrozo-dibenzilamin, N, N-dibenzilamin, organske spojine, pitna voda
Objavljeno v DKUM: 17.05.2013; Ogledov: 2298; Prenosov: 154
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10. Presence of nonylphenols in plastic films and their migration into food simulantsMarjetka Alfirević, Boštjan Križanec, Ernest Vončina, Darinka Brodnjak-Vončina, 2011, izvirni znanstveni članek Opis: Nonylphenols (NP) possess estrogenic activities and may cause increased risk of cancerous and reproductive abnormalities in several living organisms. Despite their harmful nature, NPs are used as additives in food packaging material, especially plastic, which is the main food contact material in today's packaging landscape. According to the fact that food packaging is one of the major potential food contaminant sources regarding NPs, there is a need for more information on identifying and quantifying of these chemicals when migrating into food. Seventeen plastic films for food packaging were analyzed for the presence of NPs; nine of them were plastic films for deep freeze food packaging. We determined and quantified NPs by Gas Chromatography-Mass Spectrometry (GC-MS) using the internal standard method. All plastic films for deep freeze food packaging contained NPs within a concentration range from 11.9 to 43.7 mg/kg. We also studied the migration of NPs from three of the plastic films for deep freeze food packaging into food simulants. The migration of NPs from these plastic films into 95% ethanol and 10% ethanol was higher than the amount migrating into distilled water or 3% acetic acid.
Ključne besede: nonulphenols, migration, plastic films
Objavljeno v DKUM: 01.06.2012; Ogledov: 1868; Prenosov: 122
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