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Analysis of samples with complex matrix by comprehensive gas chromatography
Šilhavecká, Simona ; Čabala, Radomír (advisor) ; Štícha, Martin (referee)
Komprehenzivní plynová chromatografie (GC×GC) je technika vhodná pro separaci komplikovaných organických směsí a nabízí mnoho výhod oproti běžné plynové chromatografii. Umožňuje kompletní analýzu vzorku současně na dvou odlišných kolonách, mezi kterými je rozhraní nazvané modulátor. Byla provedena analýza dvou éterických levandulových olejů a extraktu z levandule pomocí plynového chromatografu s pulzním tlakovým modulátorem a dvojicí detektorů: plamenově ionizačním detektorem a hmotnostním spektrometrem. Pro efektivní separaci vybraných olejů byly nalezeny optimální podmínky. Vstupní tlak na kolonu byl 250 kPa, první a druhý tlak nastavený na modulátoru byl 155 kPa a 175 kPa. Byl zvolen pomalejší teplotní program s počáteční teplotou 70 řC a nárůstem teploty 2 řC/min. Jako vhodná se ukázala modulační perioda v délce 5 s a s pulzem trvajícím 300 ms. Analyty byly identifikovány podle jejich hmotnostních spekter z MS detektoru. Nejvíce zastoupenými látkami v levandulových olejích byly terpeny. Složení levandulových olejů se liší v závislosti na druhu levandule, podmínkách pěstovaní i způsobu přípravy oleje. Klíčová slova: komprehenzivní plynová chromatografie, pulzní tlakový modulátor, levandulový olej
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Development and optimization of a robust pressure modulator for multidimensional gas chromatography
Ston, Martin
Comprehensive gas chromatography (GC×GC) is a modern and advanced analytical method designed to separate very complex samples, when the separation efficiency of classical gas chromatography is not sufficient. GC×GC allows complete simultaneous analysis of a sample on two different columns, interconnected by special interface called the modulator. Three types of control units were set up and a robust pulse flow modulator (PFM) was developed in this work. PFM working parameters have been always optimized to allow combinations of columns with different sizes. Optimized PFM allows application of columns with 10-60 m length and 0.15-0.25 mm internal diameters for the first dimensions and with 1-10 m length and 0.25-0.32 mm internal diameters for the second dimension. For demonstration reasons, analyses of complex real samples, such as essential oils, oil derivatives and biological samples, were performed. PFM was compared with the commercial cryofocusation modulator Zoex for the selected column set and one sample (a mixture of volatile solvents) on a gas chromatograph equipped with both modulators. The average repeatability of retention times, expressed as a relative standard deviation, was approximately 2.0 % for PFM (cryofocusation about 0.5 %) and of the peak areas was approximately 3.5 %...
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Development and optimization of a robust pressure modulator for multidimensional gas chromatography
Ston, Martin
Comprehensive gas chromatography (GC×GC) is a modern and advanced analytical method designed to separate very complex samples, when the separation efficiency of classical gas chromatography is not sufficient. GC×GC allows complete simultaneous analysis of a sample on two different columns, interconnected by special interface called the modulator. Three types of control units were set up and a robust pulse flow modulator (PFM) was developed in this work. PFM working parameters have been always optimized to allow combinations of columns with different sizes. Optimized PFM allows application of columns with 10-60 m length and 0.15-0.25 mm internal diameters for the first dimensions and with 1-10 m length and 0.25-0.32 mm internal diameters for the second dimension. For demonstration reasons, analyses of complex real samples, such as essential oils, oil derivatives and biological samples, were performed. PFM was compared with the commercial cryofocusation modulator Zoex for the selected column set and one sample (a mixture of volatile solvents) on a gas chromatograph equipped with both modulators. The average repeatability of retention times, expressed as a relative standard deviation, was approximately 2.0 % for PFM (cryofocusation about 0.5 %) and of the peak areas was approximately 3.5 %...
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Development and optimization of a robust pressure modulator for multidimensional gas chromatography
Ston, Martin ; Čabala, Radomír (advisor) ; Ventura, Karel (referee) ; Jelínek, Ivan (referee)
Comprehensive gas chromatography (GC×GC) is a modern and advanced analytical method designed to separate very complex samples, when the separation efficiency of classical gas chromatography is not sufficient. GC×GC allows complete simultaneous analysis of a sample on two different columns, interconnected by special interface called the modulator. Three types of control units were set up and a robust pulse flow modulator (PFM) was developed in this work. PFM working parameters have been always optimized to allow combinations of columns with different sizes. Optimized PFM allows application of columns with 10-60 m length and 0.15-0.25 mm internal diameters for the first dimensions and with 1-10 m length and 0.25-0.32 mm internal diameters for the second dimension. For demonstration reasons, analyses of complex real samples, such as essential oils, oil derivatives and biological samples, were performed. PFM was compared with the commercial cryofocusation modulator Zoex for the selected column set and one sample (a mixture of volatile solvents) on a gas chromatograph equipped with both modulators. The average repeatability of retention times, expressed as a relative standard deviation, was approximately 2.0 % for PFM (cryofocusation about 0.5 %) and of the peak areas was approximately 3.5 %...
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Analysis of phospholipids by comprehensive gas chromatography
Šilhavecká, Simona ; Čabala, Radomír (advisor) ; Jelínek, Ivan (referee)
Phospholipids are an important group of polar lipids constituting the main component of cell membranes. Their proportion may vary depending on many factors of the surrounding environment in which the cell is located. Determination of membrane phospholipids is essential in many scientific, industrial and economic sectors. The aim of this work has been to develop a separation method for determination of membrane phospholipids by which it was possible to analyze phosphorylated parts of phospholipids and fatty acids from one sample. Comprehensive gas chromatography with mass detection (GC×GC-MS) was chosen for the assay. This method allows the separation of the entire sample on two serially connected different columns, among which is the interface called modulator. The preparation of the sample includes a cleavage of the phospholipid molecule by the enzyme phospholipase C, which released the phosphorylated polar headgroups. These polar parts had to be derivatized before analysis. The principle of the chosen derivatization consisted in the use of two different silylation agents (hexamethyldisilazane and N,O-Bis(trimethylsilyl) trifluoracetamide) in two steps. Conditions were selected for efficient separation of the silylderivatives of phosphorylated headgroups using GC×GC-MS using a cryogenic...
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Analysis of samples with complex matrix by comprehensive gas chromatography
Šilhavecká, Simona ; Čabala, Radomír (advisor) ; Štícha, Martin (referee)
Komprehenzivní plynová chromatografie (GC×GC) je technika vhodná pro separaci komplikovaných organických směsí a nabízí mnoho výhod oproti běžné plynové chromatografii. Umožňuje kompletní analýzu vzorku současně na dvou odlišných kolonách, mezi kterými je rozhraní nazvané modulátor. Byla provedena analýza dvou éterických levandulových olejů a extraktu z levandule pomocí plynového chromatografu s pulzním tlakovým modulátorem a dvojicí detektorů: plamenově ionizačním detektorem a hmotnostním spektrometrem. Pro efektivní separaci vybraných olejů byly nalezeny optimální podmínky. Vstupní tlak na kolonu byl 250 kPa, první a druhý tlak nastavený na modulátoru byl 155 kPa a 175 kPa. Byl zvolen pomalejší teplotní program s počáteční teplotou 70 řC a nárůstem teploty 2 řC/min. Jako vhodná se ukázala modulační perioda v délce 5 s a s pulzem trvajícím 300 ms. Analyty byly identifikovány podle jejich hmotnostních spekter z MS detektoru. Nejvíce zastoupenými látkami v levandulových olejích byly terpeny. Složení levandulových olejů se liší v závislosti na druhu levandule, podmínkách pěstovaní i způsobu přípravy oleje. Klíčová slova: komprehenzivní plynová chromatografie, pulzní tlakový modulátor, levandulový olej
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