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Analysis of polyphenolic compounds in selected brewery matrices by HPLC-HRMS method
Zušťáková, Veronika ; Sobotníková, Jana (advisor) ; Mikyška, Alexandr (referee)
The thesis has focused on the separation of proanthocyanidins (Pas) in beer, raw beer material and beer intermediates (wort, hopped wort, green beer) by using high performance liquid chromatography coupled to high resolution mass spectrometric detection. A chromatographic column XSELECT HSS T3 was used for separation of individual proanthocyanidins. Mobile phase was formed by a mixture of 0,1% formic acid in water (A) and 0,1% formic acid in acetonitril (B), separation was conducted in gradient mode. Calibration range for catechin and procyanidin B1 a B2 was linear in the range from 10 µg.l-1 to 200 µg.l-1 and for epicatechin from 5 µg.l-1 to 200 µg.l-1 . Limit of quantitation (LOQ) was set to the lowest point of calibration curve, hence for catechin, procyanidin B1 and B2 was LOQ = 10 µg.l-1 and for epicatechin was LOQ = µg.l-1 . Yield of method of the observed Pas was very good, where yield oscillated around 100%. The method also had excellent repeatability, where the relative standard deviation (RSD) was lower then 20%. After optimization of this method it was used for observation of profile changes during brewery process in catechin, epicatechin, procyanidin B1, B2 and B3. It was discovered, that catechin, epicatechin, procyanidin B1 and B2 originate mainly from hops and procyaniding B3 is...
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Speciation analysis of arsenic-glutathione complexes by ion-pairing HPLC-ICP-MS
Zušťáková, Veronika ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The thesis has focused on the separation of arsenic-glutathione species using ion-pairing high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry. Species were separated on chromatographic column Prodigy ODS (3) using an aqueous mobile phase containing 4.7mM tetrabutylammonium hydroxide (TBAH), 2mM malonic acid and 4% methanol at pH 5.85 in the isocratic mode. Simple arsenic species - arsenite (iAsIII), arsenate (iAsV) monomethylarsenic acid (MAsIII), monomethylarsenous acid (MAsV), dimethylarsenic acid (DMAsIII) and dimethylarsenous acid (DMAsV), which served as arsenic standards to determine retention times, were successfully separated under these conditions. Arsenic-glutathione complexes As(GS)3, MAs(GS)2 and DMAs (GS) were not successfully separated. These complexes provided peaks of simple arsenic species. Peak broadening was observed in the first analysis of As(GS)3 and MAs(GS)2 complexes, which disappeared in subsequent analyses. This broadening probably represents a residual of glutathion complex which disintegrated to single species. Powered by TCPDF (www.tcpdf.org)
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Analysis of polyphenolic compounds in selected brewery matrices by HPLC-HRMS method
Zušťáková, Veronika ; Sobotníková, Jana (advisor) ; Mikyška, Alexandr (referee)
The thesis has focused on the separation of proanthocyanidins (Pas) in beer, raw beer material and beer intermediates (wort, hopped wort, green beer) by using high performance liquid chromatography coupled to high resolution mass spectrometric detection. A chromatographic column XSELECT HSS T3 was used for separation of individual proanthocyanidins. Mobile phase was formed by a mixture of 0,1% formic acid in water (A) and 0,1% formic acid in acetonitril (B), separation was conducted in gradient mode. Calibration range for catechin and procyanidin B1 a B2 was linear in the range from 10 µg.l-1 to 200 µg.l-1 and for epicatechin from 5 µg.l-1 to 200 µg.l-1 . Limit of quantitation (LOQ) was set to the lowest point of calibration curve, hence for catechin, procyanidin B1 and B2 was LOQ = 10 µg.l-1 and for epicatechin was LOQ = µg.l-1 . Yield of method of the observed Pas was very good, where yield oscillated around 100%. The method also had excellent repeatability, where the relative standard deviation (RSD) was lower then 20%. After optimization of this method it was used for observation of profile changes during brewery process in catechin, epicatechin, procyanidin B1, B2 and B3. It was discovered, that catechin, epicatechin, procyanidin B1 and B2 originate mainly from hops and procyaniding B3 is...
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Speciation analysis of arsenic-glutathione complexes by ion-pairing HPLC-ICP-MS
Zušťáková, Veronika ; Matoušek, Tomáš (advisor) ; Červený, Václav (referee)
The thesis has focused on the separation of arsenic-glutathione species using ion-pairing high performance liquid chromatography with detection by inductively coupled plasma mass spectrometry. Species were separated on chromatographic column Prodigy ODS (3) using an aqueous mobile phase containing 4.7mM tetrabutylammonium hydroxide (TBAH), 2mM malonic acid and 4% methanol at pH 5.85 in the isocratic mode. Simple arsenic species - arsenite (iAsIII), arsenate (iAsV) monomethylarsenic acid (MAsIII), monomethylarsenous acid (MAsV), dimethylarsenic acid (DMAsIII) and dimethylarsenous acid (DMAsV), which served as arsenic standards to determine retention times, were successfully separated under these conditions. Arsenic-glutathione complexes As(GS)3, MAs(GS)2 and DMAs (GS) were not successfully separated. These complexes provided peaks of simple arsenic species. Peak broadening was observed in the first analysis of As(GS)3 and MAs(GS)2 complexes, which disappeared in subsequent analyses. This broadening probably represents a residual of glutathion complex which disintegrated to single species. Powered by TCPDF (www.tcpdf.org)
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