diplomsko delo univerzitetnega študijskega programa
Saša Pušaver (Author), Darinka Brodnjak-Vončina (Mentor), Mitja Kolar (Co-mentor), Maša Islamčević Razboršek (Co-mentor)

Abstract

V okviru diplomske naloge smo želeli razviti analizno metodo za sočasno ločitev, identifikacijo in kvantitativno določanje monosaharida glukoze in sladkornega alkohola manitola v različnih vzorcih hidrolizatov biomase. Razvita metoda temelji na ločevanju in določanju preiskovanih spojin s plinsko kromatografijo in masno spektrometrijo (GC-MS). Metodo smo razvijali s čistimi standardnimi raztopinami glukoze in manitola, njeno uporabnost pa potrdili na realnih vzorcih. Podatke smo statistično ovrednotili, metodo validirali in s tem dokazali, da je le-ta pravilna in natančna. Linearnost metode smo preverili v različnih koncentracijskih območjih od 1 do 300 mg L-1, kjer so bili korelacijski koeficienti (r2) nad 0,99. Metoda je ponovljiva z relativnimi standardnimi odmiki pod 5%. Tako smo osnovne standardne raztopine preiskovanih spojin pripravili v optimalni mešanici topil metanol-voda (v/v=1/1). Ker spojine niso bile dovolj hlapne za neposredno analizo z GC-MS, smo jih predhodno, s postopkom derivatizacije oz. sililiranja, pretvorili v ustrezne trimetilsililirane (TMS) derivate. Za optimalni potek sililiranja, je bilo potrebno iz vzorcev odstraniti vse sledove vode in polarnih protonskih topil. To smo dosegli z odparevanjem vzorcev do suhega na rotacijskem uparjalniku in z dodatkom toluena k suhim preostankom. Za derivatizacijo preiskovanih spojin smo kot optimalni sililirni reagent uporabili MSTFA (N-metil-N-trimetilsilil trifluoroacetamid), kot optimalni katalizator pa piridin. Sililiranje smo izvajali pod optimalnimi pogoji na peščeni kopeli, kjer smo vzorce segrevali 90 min pri 80°C. Pred injiciranjem vzorcev na kromatografsko kolono smo le-te še dodatno redčili s toluenom ali n-heksanom. GC-MS pogoje smo izbrali tako, da smo dobili najustreznejšo ločitev in pripadajoče MS spektre preiskovanih spojin. Spojine smo identificirali s primerjavo retencijskih časov spojin pri analizi standardnih raztopin pri enakih kromatografskih pogojih, z uporabo knjižnic standardiziranih masnih spektrov in s primerjavo podatkov iz literature.

Keywords

glukoza;manitol;plinska kromatografija;masna spektrometrija;hidrolizat;

Data

Language: Slovenian
Year of publishing:
Source: Maribor
Typology: 2.11 - Undergraduate Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [S. Pušaver]
UDC: 542.2/.9(043.2)
COBISS: 16700950 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Determination of selected compounds in the biomass hidrolyzate using gas chromatography and mass spectrometry
Secondary abstract: An analytical method for the simultaneous separation, identification and determination of monosaccharide glucose and sugar alcohol mannitol in different biomass hydrolysate samples has been developed. The method is based on separation and determination of the investigated compounds by gas chromatography and mass spectrometry (GC-MS). It was developed on pure standard compounds of glucose and mannitol, and confirmed on real samples of biomass hydrolysates. Results were statistically evaluated, and method was validated in terms of linearity, reproducibility and accuracy. Results were accurate. Linearity of the method was tested in different concentration ranges from 1 to 300 mg L-1, where the correlation coefficients (r2) were greater than 0.99. The method is reproducible with relative standard deviations less than 5%. The whole procedure from sample preparation step up to the final GC-MS analysis was optimized. Stock standard solutions of the investigated compounds were prepared with the optimum solvent mixture of methanol-water (v/v = 1/1). Since the investigated compounds were not volatile enough for direct GC-MS analysis, they were previously derivatized. Using silylation reaction, they were converted to the corresponding TMS derivatives. For optimal silylation procedure, it was necessary to remove all traces of water and proton polar solvents from the samples. This condition was achieved by evaporating samples to dryness on a rotary evaporator and with the addition of toluene to dry residuals. As optimal silylation reagent MSTFA (N-methyl-N-trimethylsilyl trifluoroacetamide) was used. Pyridine was added as catalyst. Derivatization was performed under optimal conditions on the sand bath, where samples were heated 90 min at 80 °C. Before injecting samples on chromatographic column they were further diluted with toluene or n-hexane. GC-MS conditions were chosen so that the best separation and quality spectra of the investigated compounds were achieved. Compounds were identified by comparison of the retention times and mass spectras with those of pure standards obtained under the same chromatographic conditions. For identification also libraries of standardized mass spectra and literature data were used.
Secondary keywords: glucose;mannitol;gas chromatography;mass spectrometry;hydrolyzate;
URN: URN:SI:UM:
Type (COBISS): Bachelor thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: X, 50 str.
Keywords (UDC): mathematics;natural sciences;naravoslovne vede;matematika;chemistry;crystallography;mineralogy;kemija;practical laboratory chemistry;preparative and experimental chemistry;praktična laboratorijska kemija;preparativna in eksperimentalna kemija;laboratory apparatus and instrumentation in general;laboratory methods in general;
ID: 998160