Master of Science / Department of Chemistry / Christopher T. Culbertson / Chemists have been trying to relate the structure and composition of different cereal proteins to their physical properties to better inform their product use for more than 250 years now. Among these cereals, wheat is considered the most important due to its unique ability to form viscoelastic dough and retain gas during fermentation, the latter being important for bread making. This property is due to the endosperm part of wheat that contains proteins mostly gliadins and glutens. It is known that the composition and relative ratio of these proteins is determined by both the growing environment and genetics. Manipulation of the genetics allows one for control of only about 50% of the end use quality of the wheat and the rest is controlled by environment. Currently, the bread making quality of wheat is determined by baking test loaves of bread. This process is time consuming and wasteful. The main goal of this project was to create fingerprints of gliadin proteins for different wheat cultivars as a function of environmental conditions. This would then allow wheat kernels to be analyzed and assessed right after harvest to determine their appropriateness for making the various wheat products. Researchers have tried to create a catalogue of information for individual wheat cultivars by ‘fingerprinting’ the gliadins proteins in wheat using various analytical techniques including capillary electrophoresis (CE). CE offers advantages like high separation efficiency, and faster analysis. Further miniaturization of CE on microfluidic devices has enhanced the speed and efficiency of separation. Furthermore, it is possible to integrate multiple chemical analysis processes like sample preparation, separation and detection in a single microfluidics device. Microfluidic uses micron sized separation channels defined in a glass, quartz or polymer. This dissertation is focused on fabricating multilayer microfluidic devices from Poly(dimethylsiloxane) (PDMS) and using these devices to electrophoretically separate wheat gliadin proteins followed by detection using UV absorption in less than 5 min. PDMS is cheap, easy to fabricate and is optically transparent above ~230nm. Initial results of the UV absorbance detector developed for this device are presented.

Master of Science / Department of Chemistry / Christopher T. Culbertson / Chemical separation involves selective movement of a component out of a region shared by multiple components into a region where it is the major occupant. The history of the field of chemical separations as a concept can be dated back to ancient times when people started improving the quality of life by separation of good materials from bad ones. Since then the field of chemical separation has become one of the most continually evolving branches of chemical science and encompasses numerous different techniques and principles. An analytical chemist’s quest for a better way of selective identification and quantification of a component by separating it from its mixture is the cause for these ever evolving techniques. As a result, today there are numerous varieties of analytical techniques for the separation of complex mixtures. High Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), Capillary Electrophoresis (CE) and Gel Electrophoresis are a few out of a long list. Each these techniques manipulates the different physical and chemical properties of an analyte to achieve a useful separation and thus certain techniques will be suited for certain molecules. This work primarily focuses on the use of Capillary Electrophoresis as a separation technique. The mechanism of separation in Capillary Zone Electrophoresis and principles of UV detection will discussed in chapter one. Chapter two contains a discussion about the application of Capillary Electrophoresis (CE) on microfluidc devices. This will include sections on: microfabrication techniques of PDMS and photosensitized PDMS (photoPDMS), a UV detector for microfluidic devices and its application for the detection of wheat proteins. In Chapter three we report the experimental part of this project which includes; investigations on the effect of UV exposure time and thermal curing time on feature dimensions of photoPDMS microfluidic device, investigations on the injection and separation performances of the device, characterization of a UV detector set up and its application for the separation and detection of wheat gliadin proteins. The results of these investigations are presented in chapter four.

This work deals with dual detection of organic and inorganic analytes after separation by capillary zone electrophoresis. In the first part, two types of hydrodynamic sampling are tested. Standard hydrodynamic sampling most often used in laboratory-made electrophoretic apparatus, based on lifting the vessel with the sample, in which the sampling end of the capillary is immersed, and a new method based on increasing the pressure in the sampling vessel without moving the capillary. This sampling procedure minimizes experimenter activity because it is controlled by software. Experimenter only changes vessel containing the sample solution for one with separation electrolyte. The experimental parameters, the sampling time and pressure, are optimized to achieve maximum separation efficiency and adequate detection sensitivity. In the second part of the work, the developed method is tested for the separation of amino-acids in a biological sample (urine).

Volvo Cars är ett välkänt företag som säljer bilar över hela världen. Idag skickar Volvo Cars sin kylvätska till leverantörer för analys. Processen är komplicerad och tar mycket tid. Det finns ett intresse hos Volvo Cars att själva kunna analysera kylvätskan. För att kunna göra detta krävs det att en metod som de kan använda för att analysera kylvätskan utvecklas. Examensarbetet syftar till att utveckla en metod som gör det möjligt att analysera koncentrationen av organiska syror i Volvos kylvätska. Analysen ska göras med hjälp av en High Performance Liquid Chromatography - HPLC. De organiska syrorna är inhibitorer som skyddar material i motorn från korrosion när det kommer i kontakt med kylvätskan. Metoden utvecklas i flera steg, det är viktigt att veta hur olika organiska syror kan analyseras med en HPLC. HPLC-analyser är mycket beroende av de intrumentella inställningarna. Inställningarna som ändrar när metoden utvecklas är pH, typ av kolonn, våglängd på detektorn, flödeshastighet i kolonnen, injektionsvolymen, sammansättning av eluent (lösningsmedel) och analystid. Kalibreringskurvor konstrueras för att sedan kunna användas i fortsatta studier. Tre av fem organiska syror som skulle analyseras var möjliga att analysera med två olika metoder. Den enda skillnaden mellan metoderna var våglängden på detektorn. En av de organiska syrorna hade en mer linjär kalibreringskurva vid en högre våglängd. / Volvo Cars is a well-known company and they are selling their cars all over the world. Today, Volvo Cars send their engine coolant to the supplier of engine coolant for analysis. This process is complicated and takes a lot of time. It is in the interest of Volvo Cars to be able to analyze the engine coolant themselves. In order to do that, a method where they can analyze the engine coolant must be developed. This exam work aim to develop a method where it is possible to analyze the concentration of organic acids in Volvo´s engine coolant with a High Performance Liquid Chromatography - HPLC. The organic acids are inhibitors that protect the materials in the engine from corrosion when in contact with the engine coolant. The method is developed in several steps. First it is important to know how different organic acids could be analyzed with an HPLC. HPLC-analysis is very dependent of the instrumental parameters. The parameters you change when developing a method are pH, kind of column, wavelength of the detector, kind of detector, flow rate in the column, injections volume, composition of the eluent (solvent) and, analysis time. Calibration curves are created and could be used as a reference in further analysis. Three of the five organic acids that were supposed to be analyzed were possible to analyze. Three organic acids were analyzed with one method and the two remaining organic acids with another method. The only difference between the methods is the wavelengths of the detector.

This diploma thesis deals with determination of carbohydrates in wine. Theoretical part attends to production of wine from grape to treatment and training of wine. It refers saccharides in wine, especially glucose and fructose. The study provides an overview of the available sources concerning the possibilities of determination of carbohydrates in wine by chromatographic methods and Skalar automated chemistry analyser. The study shortly refers simple analytical methods for determination of wine saccharides. The experimental part based on this search deals with analysis of saccharides by high performance liquid chromatography with refractive index detector and UV detector on aminoalkyl column and determination of reducting sugars by Skalar automated chemistry analyser. Finally, the results of these methods were compared.