|
|
The problematics of identification and quantification of microplastics in soils
Polachová, Tereza ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor's thesis summarizes the current findings on the presence, behavior and analysis of microplastics in soils. The most common method for analyzing microplastics in soils is FTIR spectroscopy. However, summaries of findings and results of published research indicate insufficient standardization of sampling, purification and handling of samples. The aim was to create a mathematical model for the quantification of PET in mixtures of standard soils and PET, which was subsequently verified on mixtures of PET in different real soils. The result is a model which should be universal for the quantitative analysis of PET in standard and real soils, with low and high PET concentration. Models were created for the following wavenumbers 2965.80 cm-1; 1739.99 cm-1; 1299.85 cm-1 and 1135.31 cm-1. The correlation coefficients R2 for individual wavenumbers were: 0.9606; 0.9141; 0.9360 and 0.8879.
|
|
|
Characteristics of Moravian wines of the Pálava variety
Horáková, Lenka ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the chemical characterization of Palava wines from the Moravian region and the possibility of using chemical analysis of wines to verify the geographical origin of the Palava variety. The theoretical part of the bachelor thesis describes the wine-growing areas in the Czech Republic and the origin of the Palava variety. The theoretical part discusses the chemical composition of wine and the issue of wine adulteration and methods used to check the authenticity of wines. The experimental part of the bachelor thesis is focused on elementary analyses, analyses of selected phenolic compounds, organic acids, total phenolic compounds and antioxidant activity of wines. The measured data were evaluated using statistical analysis techniques. Analysis of variance, principal component analysis and discriminant analysis were used. The results of this work showed that with the help of chemical analyzes and statistical techniques it was not possible to distinguish samples of Pálava wines according to individual Moravian subregions. However, this study proved that the wines of the Pálava variety have a characteristic chemical composition and it can be distinguished on the basis of chemical analysis from other white wines from the wine-growing region of Moravia.
|
|
|
Study of the authenticity of spices and condiments
Štursa, Václav ; Golian, Jozef (referee) ; Urík, Martin (referee) ; Diviš, Pavel (advisor)
This disertation deals with geographical authentification of different types of spices and spice preparations. Investigated spice species were garlic (Allium sativum), ground pepper (Capsicum anuum), and dried carrot (Daucus carota). Theoretical part of the disertation describes main qualitative parameters of the examined species and production technology, means of food adulteration and statistic methods used in chemometrics. The aim of this dissertation was to verify the hypothesis whether it is possible to use targeted analytical techniques commonly used in quality control of spices and condiments, and statistical processing of measured data to distinguish samples of spices and condiments of different geographical origin. The use of non-targeted analysis was also investigated. Samples of garlic and ground pepper were used for targeted analysis. The examined parameters were dry matter and moisture of the sample, ash content, total phenolic content according to Folin-Ciocaulteu, carbohydrate content, alliin concentration, total nitrogen content, total color pigment (ASTA), pH of aqueous extract, total fat content, and concentration of selected elements (Ca, Cu, Fe, K, Mn, Mg, Na, P, Zn). The instrumental techniques used were molecular absorption spectrometry, inductively coupled plasma optical emission spectrometry and high performance liquid chromatography. The obtained data were statistically processed by analysis of variance (ANOVA) and principal component analysis (PCA). Using statistical analysis significant differences between samples that came from more distant areas were found. However, samples from closer areas could not be distinguished. The researched hypothesis could not be unequivocally confirmed or refuted. Metabolic fingerprint of carrot samples was determined using non-targeted analysis. Metabolic analysis was performed using the tandem LC-TOF-MS technique. The data were processed by recursive peak extraction (BRE) and subsequently uvaluated with PCA. The samples were divided into clusters according to their origin. Targeted and non-targeted techniques have great potential in verifying the geographical authenticity of different types of spices. However, the main condition is consistent and sufficient sampling, guaranteed information on the origin of the sample and obtaining a sufficient amount of input data for statistical analysis.
|
|
|
Using Laser-Induced Breakdown Spectroscopy (LIBS) for Material Analysis
Pořízka, Pavel ; Hrdlička, Aleš (referee) ; Pína,, Ladislav (referee) ; Kaiser, Jozef (advisor)
Tato doktorská práce je zaměřena na vývoj algoritmu ke zpracování dat naměřených zařízením pro spektrometrii laserem indukovaného plazmatu (angl. LIBS). Zařízení LIBS s tímto algoritmem by mělo být následně schopno provést třídění vzorků a kvantitativní analýzu analytu in-situ a v reálném čase. Celá experimentální část této práce byla provedena ve Spolkovém institutu pro materiálový výzku a testování (něm. BAM) v Berlíně, SRN, kde byl sestaven elementární LIBS systém. Souběžně s experimentílní prací byl vytvořen přehled literárních zdrojů s cílem podat ucelený pohled na problematiku chemometrických metod používaných k analýze LIBS měření. Použití chemometrických metod pro analýzu dat získaných pomocí LIBS měření je obecně doporučováno především tehdy, jsou-li analyzovány vzorky s komplexní matricí. Vývoj algoritmu byl zaměřen na kvantitativní analýzu a třídění vyvřelých hornin na základě měření pomocí LIBS aparatury. Sada vzorků naměřených použitím metody LIBS sestávala z certifikovaných referenčních materiálů a vzorků hornin shromážděných přímo na nalezištích mědi v Íránu. Vzorky z Íránu byly následně na místě roztříděny zkušeným geologem a množství mědi v daných vzorcích bylo změřeno na Univerzitě v Clausthalu, SRN. Výsledné kalibrační křivky byly silně nelineární, přestože byly sestaveny i z měření referenčních vzorků. Kalibrační křivku bylo možné rozložit na několik dílčích tak, že závislost intenzity měděné čáry na množství mědi se nacházela v jiném trendu pro jednotlivé druhy hornin. Rozdělení kalibrační křivky je zpravidla přisuzováno tzv. matričnímu jevu, který silně ovlivňuje měření metodou LIBS. Jinými slovy, pokud určujeme množství analytu ve vzorcích s různou matricí, je výsledná kalibrační křivka sestavená pouze z jedné proměnné (intenzity zvolené spektrální čáry analytu) nepřesná. Navíc, normalizace takto vytvořených kalibračních křivek k intenzitě spektrální čáry matrčního prvku nevedla k výraznému zlepšení linearity. Je obecně nemožné vybrat spektrální čáru jednoho matričního prvku pokud jsou analyzovány prvky s komplexním složením matric. Chemometrické metody, jmenovitě regrese hlavních komponent (angl. PCR) a regrese metodou nejmenších čtverců (angl. PLSR), byly použity v multivariační kvantitatvní analýze, tj. za použití více proměnných/spektrálních čar analytu a matričních prvků. Je potřeba brát v potaz, že PCR a PLSR mohou vyvážit matriční jev pouze do určité míry. Dále byly vzorky úspěšně roztříděny pomocí analýzy hlavních komponent (angl. PCA) a Kohonenových map na základě složení matričních prvků (v anglické literatuře se objevuje termín ‚spectral fingerprint‘) Na základě teorie a experimentálních měření byl navržen algoritmus pro spolehlivé třídění a kvantifikaci neznámých vzorků. Tato studie by měla přispět ke zpracování dat naměřených in-situ přístrojem pro dálkovou LIBS analýzu. Tento přístroj je v současnosti vyvíjen v Brně na Vysokém učení technickém. Toto zařízení bude nenahraditelné při kvantifikaci a klasifikaci vzorků pouze tehdy, pokud bude použito zároveň s chemometrickými metodami a knihovnami dat. Pro tyto účely byla již naměřena a testována část knihoven dat v zaměření na aplikaci metody LIBS do těžebního průmyslu.
|
|
|
Analysis of VOC Frankovka wines originating in the Modré hory region
Horáková, Lenka ; Machát,, Jiří (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the chemical characterization of Frankovka red wines and the possibility of using chemical analysis of wines to distinguish Frankovka wines from VOC Modré hory from other Frankovka wines from the Moravian wine region. The theoretical part describes viticulture in the Czech Republic, the characteristics of the Frankovka variety and the wine classification system in the Czech Republic. The next part describes in detail the association VOC Modré hory, the red wine technology and the use of chemometry for wine authentication. The experimental part deals with the determination of the elemental profile of wines by ICP-MS and ICP-OES methods, analysis of selected phenolic substances by HPLC-MS and analysis of organic acids by IC. Furthermore, the analysis of the aromatic profile of wines was performed using the technique HS-SPME-GC-MS and the total content of phenolic substances in wines was determined by the MAS method. A total of 24 wine samples were analyzed, where 12 samples came from VOC Modré hory and another 12 wines came from other Moravian wine regions. Statistical analysis techniques (Mann-Whitney U-test and PCA) were used to classify wine samples into groups in order to separate wines from VOC Modré hory and other wines from other Moravian regions. The results of this work showed that with the help of chemical analyzes and statistical techniques it was possible to distinguish wines from VOC Modré hory from other wines from the Moravian wine region.
|
|
|
Studying the authenticity of coffee of various geographical origins
Flegr, Šimon ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This diploma thesis researches coffee authenticity problematice, mainly focusing on the authenticity of geographic origin. In the theoretical part of this work, botanical classification is described as well as production technology and processes. The work also includes chemical composition of coffee, describing the major components and changes during production phases. It describes major production areas of the world, in terms of general description and brief history. Problematics with coffee fraud and its identification are also described. Theoretical part also includes general geological description of 17 studied coffee growing regions. Experimental part is devoted to trace amount analysis of selected elements and volatile compounds. The element analysis was conducted using mass spectrometry or optical emission spectrometry, volatile compounds were determined using gas chromatography combined with mass spectrometry detection. Results were statistically described and analyzed, resulting in several discrimination models based on geographic origin.
|
|
|
Application of analytical techniques and chemometry for authentification of wine
Pořízka, Jaromír ; Karovičová, Jolana (referee) ; Jarošová, Alžběta (referee) ; Diviš, Pavel (advisor)
This PhD. thesis is focused on application of different analytical techniques for determination of elemental composition of Moravian wine combined with analysis of selected polyphenol compounds. Two spectrometric techniques were used for elemental analysis of wine – Mass spectrometry and Optical emission spectrometry with inductively coupled plasma (ICP-MS and ICP-OES). Analysis of organic constituents of wine was evaluated by High performance liquid chromatograph with diode array detector (HPLC-DAD). Data from analysis of wine were used for construction of mathematical models for determining geographical origin of wine and for determining type of varietal wine. Data handling was performed by usage of multivariate statistical methods (cluster analysis, principal component analysis and canonical discriminant analysis). For the discrimination of wine by the geographical origin, two separate models for white and red wine were constructed. Effectiveness of discrimination of Moravian wine (with knowledge about origin) into 4 wine regions was 100 % successful for white wine and 96,43 % for red wine samples. Those models were used for cross validation test of unknown samples with result 95 % successfully classified samples of white wine and 82,15% of red wine. Besides that, mathematical model for discrimination and classification of varietal wine was made. Müller Thurgau, Riesling and Gruner Veltliner were discriminated by the usage of 8 elemental parameters. Discrimination success rate of known samples was evaluated by canonical discriminant analysis with 95,83% of correctly classified known samples and 70,83% of correctly classified unknown varietal wine (cross validation test). In addition to these part of research, impact of different grape production systems on elemental composition of wine and Vitis Vinifera was studied. The core of the study was to find the connections between the type of agriculture and chemical properties of wine and Vitis Vinifera. Two agriculture systems were assessed – Organic agriculture and Integrated pest management. . Results of this study showed that quantity and manner of pesticide application is very important factor affecting the final elemental composition of the grapevine and wine, especially the content of copper, zinc and manganese. That knowledge can be used in the future for creation of classification model of wine according to grape production system. For comparison of radical scavenging activity, electron paramagnetic resonance spectroscopy (EPR) with DPPH method was used. In the case of this study, the influence of vine growing under different farming systems on the total antioxidant activity of wine was found to be insignificant.
|
|
|
Analysis of VOC Frankovka wines originating in the Modré hory region
Horáková, Lenka ; Machát,, Jiří (referee) ; Diviš, Pavel (advisor)
This diploma thesis deals with the chemical characterization of Frankovka red wines and the possibility of using chemical analysis of wines to distinguish Frankovka wines from VOC Modré hory from other Frankovka wines from the Moravian wine region. The theoretical part describes viticulture in the Czech Republic, the characteristics of the Frankovka variety and the wine classification system in the Czech Republic. The next part describes in detail the association VOC Modré hory, the red wine technology and the use of chemometry for wine authentication. The experimental part deals with the determination of the elemental profile of wines by ICP-MS and ICP-OES methods, analysis of selected phenolic substances by HPLC-MS and analysis of organic acids by IC. Furthermore, the analysis of the aromatic profile of wines was performed using the technique HS-SPME-GC-MS and the total content of phenolic substances in wines was determined by the MAS method. A total of 24 wine samples were analyzed, where 12 samples came from VOC Modré hory and another 12 wines came from other Moravian wine regions. Statistical analysis techniques (Mann-Whitney U-test and PCA) were used to classify wine samples into groups in order to separate wines from VOC Modré hory and other wines from other Moravian regions. The results of this work showed that with the help of chemical analyzes and statistical techniques it was possible to distinguish wines from VOC Modré hory from other wines from the Moravian wine region.
|
|
|
Study of the authenticity of spices and condiments
Štursa, Václav ; Golian, Jozef (referee) ; Urík, Martin (referee) ; Diviš, Pavel (advisor)
This disertation deals with geographical authentification of different types of spices and spice preparations. Investigated spice species were garlic (Allium sativum), ground pepper (Capsicum anuum), and dried carrot (Daucus carota). Theoretical part of the disertation describes main qualitative parameters of the examined species and production technology, means of food adulteration and statistic methods used in chemometrics. The aim of this dissertation was to verify the hypothesis whether it is possible to use targeted analytical techniques commonly used in quality control of spices and condiments, and statistical processing of measured data to distinguish samples of spices and condiments of different geographical origin. The use of non-targeted analysis was also investigated. Samples of garlic and ground pepper were used for targeted analysis. The examined parameters were dry matter and moisture of the sample, ash content, total phenolic content according to Folin-Ciocaulteu, carbohydrate content, alliin concentration, total nitrogen content, total color pigment (ASTA), pH of aqueous extract, total fat content, and concentration of selected elements (Ca, Cu, Fe, K, Mn, Mg, Na, P, Zn). The instrumental techniques used were molecular absorption spectrometry, inductively coupled plasma optical emission spectrometry and high performance liquid chromatography. The obtained data were statistically processed by analysis of variance (ANOVA) and principal component analysis (PCA). Using statistical analysis significant differences between samples that came from more distant areas were found. However, samples from closer areas could not be distinguished. The researched hypothesis could not be unequivocally confirmed or refuted. Metabolic fingerprint of carrot samples was determined using non-targeted analysis. Metabolic analysis was performed using the tandem LC-TOF-MS technique. The data were processed by recursive peak extraction (BRE) and subsequently uvaluated with PCA. The samples were divided into clusters according to their origin. Targeted and non-targeted techniques have great potential in verifying the geographical authenticity of different types of spices. However, the main condition is consistent and sufficient sampling, guaranteed information on the origin of the sample and obtaining a sufficient amount of input data for statistical analysis.
|
|
|
Characteristics of Moravian wines of the Pálava variety
Horáková, Lenka ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the chemical characterization of Palava wines from the Moravian region and the possibility of using chemical analysis of wines to verify the geographical origin of the Palava variety. The theoretical part of the bachelor thesis describes the wine-growing areas in the Czech Republic and the origin of the Palava variety. The theoretical part discusses the chemical composition of wine and the issue of wine adulteration and methods used to check the authenticity of wines. The experimental part of the bachelor thesis is focused on elementary analyses, analyses of selected phenolic compounds, organic acids, total phenolic compounds and antioxidant activity of wines. The measured data were evaluated using statistical analysis techniques. Analysis of variance, principal component analysis and discriminant analysis were used. The results of this work showed that with the help of chemical analyzes and statistical techniques it was not possible to distinguish samples of Pálava wines according to individual Moravian subregions. However, this study proved that the wines of the Pálava variety have a characteristic chemical composition and it can be distinguished on the basis of chemical analysis from other white wines from the wine-growing region of Moravia.
|
guest ::
