Dissertations / Theses on the topic 'Ethylene sensor'

En la presente tesis doctoral se han desarrollado dispositivos electroquímicos de estado sólido para la detección selectiva de hidrocarburos en los gases de escape de coches. Diversos materiales fueron empleados para ello. También se llevó a cabo la activación catalítica del electrodo de trabajo para mejorar la reacción electroquímica del analito objetivo. El etileno fue seleccionado como el analito objetivo para cuantificar la cantidad total de hidrocarburos ya que es uno de los hidrocarburos más abundantes en un gas de escape. Pero el dispositivo no solo debe proporcionar una respuesta selectiva al etileno, sino que también debe tener una baja sensibilidad cruzada a otros compuestos también abundantes en un gas de escape como monóxido de carbono, agua, dióxido de nitrógeno, etc. El dispositivo consiste en un sensor potenciométrico de estado sólido en el que óxido de zirconio estabilizado con 8% de óxido de itrio (8YSZ) es empleado como electrolito. Dos electrodos son impresos en la superficie de cada cara. Primero, diversos óxidos fueron empleados como electrodo de trabajo utilizando a su vez platino como electrodo de referencia a 550ºC. Muchos de los materiales fueron descartados por su falta de selectividad al etileno, su alta sensibilidad cruzada al monóxido de carbono o por su respuesta no estable. Finalmente, Fe0.7Cr1.3O3 mezclado con 8YSZ fue seleccionado como el material más prometedor dada su buena selectividad al etileno con baja sensibilidad cruzada al monóxido de carbono. Esta configuración fue expuesta a agua como a fenantreno y metilnaftaleno. Esto produjo un aumento de la sensibilidad cruzada del dispositivo al monóxido de carbono, motivo por el que el sensor no sea adecuado para los objetivos de esta tesis. La estrategia adoptada consistió en actuar sobre el electrodo de referencia. El Platino, empleado habitualmente en la bibliografía como electrodo de referencia, fue cambiado por un conductor mixto iónico-electrónico activo al oxigeno: La0.8Sr0.2MnO3 mezclado con 8YSZ (LSM/8YSZ). Desgraciadamente, esto provocó un aumento de la sensibilidad cruzada al monóxido de carbono. Diversas nanopartículas fueron añadidas en el electrodo de trabajo para mejorar la actividad catalítica y aumentar la reacción electroquímica al etileno. Níquel, titanio y aluminio (especialmente la combinación de los dos últimos con níquel) dieron la mejor respuesta: el sensor era selectivo al etileno con baja sensibilidad cruzada al monóxido de carbono, agua y fenantreno. El efecto del espesor del electrolito en la respuesta del sensor también fue evaluado en un rango de 0.1 a 1.2 mm. Aunque no había una gran diferencia en la respuesta, la sensibilidad cruzada al monóxido de carbono era menor en el caso del dispositivo más fino. Otras alternativas al 8YSZ como electrolito también fueron evaluadas para trabajar a menores temperaturas (400 a 550ºC): oxido de cerio dopado con gadolinio (CGO) y óxido de zirconio estabilizado con un 10% de óxido de escandio (ScSZ). El dispositivo basado en ScSZ mostró un buen comportamiento a etileno a bajas temperaturas y en condiciones secas pero la adición de agua provocaba un aumento de la sensibilidad cruzada al monóxido de carbono. Una vez infiltrado el electrodo de trabajo con níquel, ambos dispositivos mostraron un buen comportamiento a bajas temperaturas en condiciones secas para concentraciones de etileno inferiores a 100 ppm, aunque la mejor respuesta fue obtenida a 550ºC. Ambos dispositivos mostraron una respuesta selectiva al etileno con baja sensibilidad cruzada al monóxido de carbono, agua y fenantreno. Se estudió también el efecto de mezclar el electrodo de trabajo con un conductor iónico (8YSZ). Se mezcló La0.87Sr0.13CrO3 (LSC) con 8YSZ sin observarse un cambio en la respuesta comparado con el electrodo solo. Además la mejor configuración Fe0.7Cr1.3O3/8YSZ//8YSZ//LSM/8YSZ (infiltrado con níquel) fue expuesto a dioxide de nitr
The present thesis is focused on the development of solid-state electrochemical devices for the selective detection of hydrocarbons in car exhaust gases. For this purpose, several materials were tested as electrodes and electrolytes. Catalytic activation of the working electrode has also been taken into account to boost the electrochemical reaction of the target analyte. Ethylene is one of the most abundant hydrocarbons in an exhaust gas and was selected as the target analyte to quantify the total amount of hydrocarbons. Not only the device has to be selective to ethylene but it must also have a low cross-sensitivity toward other pollutants abundant in an exhaust gas such as carbon monoxide, water, other hydrocarbons, nitrogen dioxide, etc. Thus, a solid-state potentiometric sensor was selected based on 8% Ytria-stabilized Zirconia (8YSZ) as electrolyte. Two electrodes were screen-printed on top of each face. First, several metal oxides were tested as working electrode with platinum (Pt) as reference electrode at 550ºC. Most of the materials were discarded because of their lack of selectivity to ethylene, high cross-sensitivity toward carbon monoxide or problems regarding stability. Fe0.7Cr1.3O3 mixed with 8YSZ was finally selected as the most promising material because of its selective response to ethylene with relatively low cross-sensitivity toward carbon monoxide. This sensor configuration was then exposed to water and phenanthrene and methylnaphthalene. This led to an increase of the cross-sensitivity of the device toward carbon monoxide making the device not suitable for the purposes of the present thesis. The approach to improve the sensor performance was to modify the reference electrode. Platinum, usually employed in literature as reference electrode, was exchanged for a mixed ionic-electronic conductor active to oxygen: La0.8Sr0.2MnO3 mixed with 8YSZ (LSM/8YSZ). Unfortunately, this increases the device activity toward carbon monoxide increasing its cross-sensitivity. Several nanoparticles were added onto the working electrode to improve the catalytic activity and boost the electrochemical reaction of ethylene. Nickel, titanium and aluminum (the last two elements combined with nickel) provided the best performance: selectivity to ethylene with low cross-sensitivity toward carbon monoxide, water and phenanthrene. The effect of the electrolyte thickness was also checked in the range from 0.1 to 1.2 mm. Although there was not a huge difference between them, the cross-sensitivity toward carbon monoxide was slightly lower for the thinnest sensor. Other alternatives to 8YSZ electrolyte were tested at lower working temperatures (400 to 550ºC) with the same electrodes materials: gadolinium-doped cerium oxide (CGO) and 10% scandia-stabilized Zirconia (ScSZ). ScsZ-based device showed a good performance in dry conditions but the addition of water decreased its suitability. Once improved the catalytic activity of the working electrode, both devices showed a good performance at lower temperature in dry conditions for ethylene concentration above 100 ppm but the best response was achieved at 550ºC. Both devices were selective to ethylene with low cross-sensitivity toward carbon monoxide, water and phenanthrene. The effect of mixing the working electrode with an ionic conductor (8YSZ) was also tested by mixing La0.87Sr0.13CrO3 (LSC) with 8YSZ and no change in response was observed when compared to the bare electrode. Finally, the best sensor configuration Fe0.7Cr1.3O3/8YSZ//8YSZ//LSM/8YSZ (after infiltration with nickel) was exposed to nitrogen dioxide to check the cross-sensitivity. The response was still selective to ethylene even with the addition of nitrogen dioxide plus water.
En la present tesi doctoral s'han desenvolupat dispositius electroquímics d'estat sòlid per a la detecció selectiva d' hidrocarburs als gasos d'escapament dels automòbils. Diversos materials van ser empleats per a tal fi. També es va dur a terme l'activació catalítica de l'elèctrode de treball per a millorar la reacció electroquímica al anàlit objectiu. L' etilè va ser seleccionat com anàlit objectiu per a quantificar la quantitat total d' hidrocarburs, ja que és un dels hidrocarburs més abundants en un gas d'escapament. Però el dispositiu no ha de ser tan sols selectiu a l'etilè, sinó que també deu proporcionar una baixa sensibilitat creuada a altres elements força abundants en un gas d'escapament com són el monòxid de carboni, l'aigua, el diòxid de nitrogen, etc. Així, el dispositiu consisteix en un sensor potenciomètric d'estat sòlid en el que l'òxid de zirconi estabilitzat amb un 8% d'òxid d'itri (8YSZ) és empleat como a electròlit. Els elèctrodes van impresos a cadascuna de les superfícies del dispositiu. Primer, diversos òxids es van emprar com a elèctrode de treball fent servir platí com elèctrode de referència a 550ºC. Molts dels materials van ser descartats per motiu de la seva manca de selectivitat al etilè, la seva alta sensibilitat creuada al monòxid de carboni o perquè la resposta no era estable. Finalment, el Fe0.7Cr1.3O3 mesclat amb 8YSZ va ser seleccionat com el material més prometedor atès a la selectivitat a l'etilè i la baixa sensibilitat creuada al monòxid de carboni. Aquesta configuració és doncs exposada tant a l'aigua com al fenantrè i al metilnaftalè. Això va produir un increment de la sensibilitat creuada al monòxid de carboni, fent que el dispositiu no resulti idoni per als objectius de la present tesi. Es va adoptar com a estratègia modificar l'elèctrode de referència. Platí, empleat sovintment com a elèctrode de referència a la bibliografia, va ser canviat per un conductor mixt iònic-electrònic actiu a l'oxigen: La0.8Sr0.2MnO3 mesclat amb 8YSZ (LSM/8YSZ). Malauradament, això va provocar l'augment de la sensibilitat creuada al monòxid de carboni. Diverses nanopartícules van ser afegides al elèctrode de treball per tal de millorar la seva activitat catalítica i així augmentar la reacció electroquímica de l'etilè. Níquel, titani i alumini (especialment la combinació dels dos darrers amb níquel) van donar la millor resposta: el sensor era selectiu a l¿etilè amb una baixa sensibilitat creuada al monòxid de carboni, l'aigua i al fenantrè. L'efecte del espessor del electròlit a la resposta del sensor també va ser avaluada en un rang de 0.1 a 1.2 mm. Malgrat que no hi ha una gran diferència en la resposta, la sensibilitat creuada al monòxid de carboni és menor en el cas del dispositiu més prim. Altres alternatives al 8YSZ com a electròlit van ser també avaluades per tal de treballar a temperatures menors (400 a 550ºC): òxid de ceri dopat amb gadolini (CGO) i òxid de zirconi estabilitzat amb un 10% d'òxid d'escandi (ScSZ). El dispositiu basat en ScSZ va mostrar un bon comportament a l'etilè a baixes temperatures en condiciones seques, però la adició d'aigua provocava un augment de la sensibilitat creuada al monòxid de carboni. Una vegada que l'elèctrode de treball es infiltrat amb níquel, ambdós dispositius mostraren un bon comportament a baixes temperatures en condicions seques per a concentracions d'etilè menors de 100 ppm, encara que la millor resposta fou obtinguda a 550ºC. La resposta era selectiva a l'etilè amb una baixa sensibilitat creuada al monòxid de carboni, l'aigua i el fenantrè. Es va comprovar també l'efecte de mesclar l'elèctrode de treball amb un conductor iònic (8YSZ). Es va mesclar La0.87Sr0.13CrO3 (LSC) amb 8YSZ sense observa cap canví en la resposta comparada amb l'electrode sense 8YSZ. la millor configuració Fe0.7Cr1.3O3/8YSZ//8YSZ//LSM/8YSZ (infiltrado con níquel) fou exposada
Toldra Reig, F. (2018). Development of electrochemical devices for hydrocarbon sensing purposes in car exhaust gases [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/110968
TESIS

In smart textiles, electrical conductivity is often required for several functions, especially contacting (electroding) and interconnecting. This thesis explores electrically conductive textile surfaces made by combining conventional textile coating methods with the intrinsically conductive polymer complex poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). PEDOT:PSS was used in textile coating formulations including polymer binder, ethylene glycol (EG) and rheology modifier. Shear viscometry was used to identify suitable viscosities of the formulations for each coating method. The coating methods were knife coating, pad coating and screen printing. The first part of the work studied the influence of composition of the coating formulation, the amount of coating and the film formation process on the surface resistivity and the surface appearance of knife-coated textiles. The electrical resistivity was largely affected by the amount of PEDOT:PSS in the coating and indicated percolation behaviour within the system. Addition of a high-boiling solvent, i.e. EG, decreased the surface resistivity with more than four orders of magnitude. Studies of tear strength and bending rigidity showed that textiles coated with formulations containing larger amounts of PEDOT:PSS and EG were softer, more ductile and stronger than those coated with formulations containing more binder. The coated textiles were found to be durable to abrasion and cyclic strain, as well as quite resilient to the harsh treatment of shear flexing. Washing increased the surface resistivity, but the samples remained conductive after five wash cycles. The second part of the work focused on using the coatings to transfer the voltage signal from piezoelectric textile fibres; the coatings were first applied using pad coating as the outer electrode on a woven sensor and then as screen-printed interconnections in a sensing glove based on stretchy, warp-knitted fabric. Sensor data from the glove was successfully used as input to a microcontroller running a robot gripper. These applications showed the viability of the concept and that the coatings could be made very flexible and integrated into the textile garment without substantial loss of the textile characteristics. The industrial feasibility of the approach was also verified through the variations of coating methods.

The sensing needs for the fresh produce industry can be split into two primary stages: during maturation in the field, also referred to as Precision Farming, and during storage and transport of the produce, or Postharvest Storage. This work seeks to improve the accuracy and reliability of commercially available electrochemical and spectroscopic sensors tailored to the sensing needs of the fresh produce industry. For electrochemical sensing, this study proposes the use of an inline filter to remove polar organic compounds, which can interfere with the readings of a platinum-based electrochemical sensor. A 50% improvement in measurement accuracy was achieved when monitoring the storage headspace of a container of apples. For portable spectroscopy instruments, this study suggests improvements for the alignment of the optical bench and the spectral collect protocol. Methods to reduce the influence of environmental noise, such as variability of background light (sunlight in the field) and thermal effects on hardware performance, are presented. This study also presents the first report of the calibration transfer of spectral regressions developed with Karl Norris's Derivative Quotient Method. The motivation for this aspect of research was to develop methods to collect stable and accurate data in the field, which can be used to improve the quality of fresh produce reaching the customer and reduce premature food spoilage.

 

Control of protein immobilization at sensor surfaces is of great interest within various scientific fields, since it enables studies of specific biomolecular interactions. To achieve this, one must be able to immobilize proteins with retained native structure, while minimizing non-specific protein binding. The high affinity interaction between streptavidin (SA) and biotin is extensively used as a linker between a surface, where SA is immobilized, and the (biotinylated) molecule of interest. Self- assembled monolayers (SAMs) of poly- and oligo ethylene glycol (PEG and OEG) derivatives have been proven in literature to minimize non-specific protein binding, and biotin-exposing SAMs have been shown efficient for immobilization of SA.

The aim of this master's thesis project was to develop biotinylated gold surfaces for quartz crystal microbalance with dissipation monitoring (QCM-D) applications through the self-assembly of mixed monolayers of thiolated OEG (or PEG) derivatives with or without a terminal biotin head group. For this, different thiol compounds were to be compared and evaluated. For the systems under study, the required biotin density for maximum specific SA immobilization was to be established, while keeping the non-specific serum adsorption at a minimum. Model experiments with biotinylated proteins immobilized to the SA-functionalized surfaces were to be performed to evaluate the possibilities for commercialization.

A protocol for the preparation of a novel biotinylated surface was developed based on the immersion of gold substrates in an ethanolic incubation solution of dithiols with OEG chains (SS-OEG and SS-OEG-biotin, 99:1) and found to give reproducible results with respect to low non-specific protein binding and immobilization of a monolayer of SA. The modified surfaces allowed for subsequent immobilization of biotinylated bovine serum albumin (bBSA) and biotinylated plasminogen (bPLG). PLG was the subject of a challenging case study, using a combination of QCM-D and surface plasmon resonance (SPR), where the immobilized protein was subjected to low molecular weight ligands that were believed to induce conformational changes. The high control of the surface chemistry allowed for the interpretation of the increased dissipation shift upon ligand binding in terms of conformational changes.

An obstacle before commercialization of the described biotinylated surfaces is that they do not seem stable for storage > 7 days. The reasons for this have to be investigated further.

A goiaba vermelha é pouco conhecida pelos mercados importadores, porém tem um potencial de comercialização bastante grande, pois a goiaba é considerada um dos frutos mais completos em termos nutricionais. Porém, a presença de moscas-das-frutas nos frutos leva países importadores a impor restrições comerciais por motivos fitossanitários. Os EUA permitem que a irradiação seja utilizada para controle quarentenário de Anastrepha spp. E Ceratitis capitata, com dose mínima de 150 Gy e 225 Gy, respectivamente. Como existe variação de dose dentro do container irradiado, que pode ser de 1:3, frutos deverão apresentar qualidade comercial mesmo quando submetidos a doses até três vezes maiores que a dose mínima de controle. Portanto, este trabalho verificou a qualidade de goiabas Pedro Sato irradiadas com 150 e 450 Gy e, também, com 225 e 675 Gy que representam as doses mínimas e máximas para controle quarentenário de Anastrepha spp. e C. Capitata, respectivamente. No primeiro experimento, goiabas foram irradiadas com 0, 150, 225, 450, 675 Gy e avaliadas a 0, 2, 4 e 6 dias após a irradiação para as análises físico-químicas. As determinações de incidência de doenças e escurecimento da casca, taxa respiratória e produção de etileno foram realizadas diariamente. As análises sensoriais ocorreram 5 dias após irradiação, sendo que as organolépticas foram irradiadas com 0, 225 e 675 Gy. As goiabas deste experimento foram armazenadas a 23 mais ou menos 1oC e 85 mais ou menos 5% UR. Os resultados indicaram que a irradiação acelerou o amadurecimento das goiabas, predispôs os frutos a doenças e favoreceu a perda de massa. A taxa respiratória e a produção de etileno foram maiores para os frutos irradiados até o quarto dia de armazenagem. Em relação às análises sensoriais, foi verificada qualidade organoléptica superior dos frutos não irradiados. No segundo experimento as doses aplicadas foram idênticas ao primeiro experimento. Goiabas foram armazenadas sob temperatura de refrigeração (TR) de 10 mais ou menos 1oC e 80 mais ou menos 5% UR e analisadas a 0, 7 e 14 dias, sendo que aos 7 e 14 dias as goiabas foram transferidas à temperatura ambiente (TA) de 23 mais ou menos 1oC e 70 mais ou menos 5% UR durante dois dias quando foram novamente analisadas. As análises sensoriais foram realizadas nas goiabas armazenadas por 7 e 14 dias a TR + 2 a TA. Os resultados demonstram que goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA estavam amolecidas e as irradiadas com 450 e 675 Gy apresentaram coloração interna menos intensa. Além destas alterações, frutos irradiados armazenados por 14 dias a TR + 2 a TA apresentaram incidência de casca escurecida e maior perda de massa. Em relação às análises sensoriais, goiabas irradiadas armazenadas por 7 dias a TR + 2 a TA apresentaram qualidade organoléptica aceitável, embora inferior às não irradiadas. Já as goiabas armazenadas por 14 dias a TR + 2 a TA apresentaram qualidade inaceitável quando irradiadas com 675 Gy, enquanto que as não irradiadas e as irradiadas com 225 Gy foram apenas um pouco superiores ao limite aceitável
Red guava is not a well-known fruit by importing markets; however, it has a great commercial potential, since it is considered one of the most complete fruits in terms of nutritional quality. However, the presence of fruit-flies in fruits leads importing countries to impose commercial restrictions due to phytosanitary risk. The USA permit the use of irradiation to the quarantine control of Anastrepha spp. and Ceratitis Capitata with a minimum dose of 150 and 225 Gy, respectively. Since, there is a dose variation inside na irradiated container, which can be of 1:3, fruits must present commercial quality, even after irradiation with doses of up to three times higher than the minimum required dose. Therefore this works objective was the study of the quality of Pedro Sato guavas irradiated with 150 and 450 Gy and, also, 225 and 675 Gy, which represented minimum and maximum doses of quarantine control of Anastrepha spp. and C. capitata, respectively. In the first experiment, guavas were irradiated with 0, 150, 225, 450, 675 Gy and evaluated at 0, 2, 4 e 6 days after irradiation for the physic-chemical analysis. The determinations of disease incidence, peel darkening incidence, respiration rate and ethylene production was done in a daily basis. The sensory assessments took place 5 days after irradiation, in which the organoleptic assessments were irradiated with 0, 225 e 675 Gy. Guavas during this experiment were stored at 23 more or less 1oC e 85 more or less 5% RH. The results indicate that irradiation speeded up the ripening of guavas, increased disease incidence and mass loss. The respiratory rate and ethylene production was higher to the irradiated fruits until the fourth day of storage. In relation to the sensory analysis, superior organoleptic quality was found in non-irradiated fruits. In the second experiment, applied doses were identical to the ones of the firs experiment. Guavas were stored under refrigerated temperature (RT) at 10 more or less 1oC and 80 more or less 5% UR and analyzed at 0, 7 and 14 days; at 7 e 14 days guavas were transferred to ambient temperature (AT) of 23 more or less 1oC and 70 more or less 5% UR during two days to be analyzed again. Sensory analysis were made in guavas stored for 7 and 14 days at RT + 2 at AT. The results showed that irradiated guavas stored by 7 days at RT + 2 at AT were softened and the ones irradiated with 450 e 675 Gy presented pulp color less intense. In addition to these alterations irradiated guavas stored for 14 days at RT + 2 at AT presented incidence of peel darkening and higher mass loss. In relation to the sensory analysis, irradiated guavas stored for 7 days at RT + 2 at AT presented acceptable organoleptic quality, although inferior to the non-irradiated ones. In the other hand, guavas stored for 14 days at RT + 2 a AT presented unacceptable quality when irradiated with 675 Gy, whereas the non-irradiated and the irradiated with 225 Gy were only barely acceptable

碩士
輔仁大學
食品科學系碩士班
103
Horticultural products are rich in bioacitive compounds, such as lycopene and anthocyanins. Those phytochemicals lead to bright colors, and impart good antioxidant capacity. The aims of this study were to use an ethylene sensor in intelligent package to indicate quality of horticultural products during storage. The ethylene sensor was prepared using molybdenum, palladium and tin ions, and immobilized on surface-modified LDPE, then applied to horticultural products. Packaged banana and tomato exposed to ethyelen or 1-MCP during storage, and Phalaenopsis exposed to ethylene during transportation for 0.5 - 4 hrs were accomplished, and quality attributes of appearance, texture and flowering were analyzed from those horticultural products during storage. Bioactive compounds, including solvent extracted lycopene and anthocyanins, were then subjected to HPLC for identification and quantification. Results showed that ethylene was produced in banana package during storage, what caused ripeness including weight loss, texture softening, discoloration and Brix increase. However, ripening was significantly suppressed in the presence of 1-MCP. Increase of color development (ΔE) on sensor was found corresponding to ethylene content, indicating the ethylene sensor is effective to monitor banana storage quality. Ethylene exposure resulted to fewer lycopene formation in tomato, resulting in less peel redness during ripening. Additionally, no significant difference between air and ethylene-treated tomatos from color development on ethylene sensor was found. Phalaenopsis exposed to ethylene for 2 and 4 hr led to significantly increase the percentage of withered flowers, and lower cyanidin contents. Those conditions caused ΔE on sensor to 3.68 and 6.79, respectively, indicating the sensor is effective to monitor flowering life of Phalaenopsis in vase. Conclusively, ethylene sensor composed of multi-metal ions is efficacy for ethylene detection, and determination of horticultural product quality.

碩士
國立臺灣大學
化學工程學研究所
90
Ethylene is an important plant growth hormone. It regulates the growth and development of a plant. Measurement of the concentration of ethylene during plant cell culture is necessary for elucidating a cultivation system. Electrochemical sensor was fabricated by chemical deposition gold onto a Nafion membrane ( Type 117, H+ form ). Oxidation current of ethylene was at 1100 mV ( vs. Ag / AgCl ). When preparing the Gold / Nafion electrode, the hydrogen bubbles generated from electrochemical reaction adhered onto the membrane, causing the deterioration of the adsorptivity of gold on Nafion. To improve this problem, the chemical deposition apparatus was modified by incorporating the magnetic stirrers. This was effective in dispelling the hydrogen gas and resulted in a rather tough Gold / Nafion electrode with high roughness factor. The detecting limit of sensor was 0.055 ppm and the sensitivity was 0.39 A / ppm. The sensor devised in this study was employed to an on-line monitoring of PC2H4 of a bioreactor ( 2L working volume ) cultivating ginseng cells ( Panax ginseng ).

碩士
輔仁大學
食品科學系碩士班
102
Ethylene gas has been used as an indicator to monitor ripening. Traditional analyses of ethylene are complicated and require expensive instrumentation, thus, fast and handy methods are of importance. Sensors used in smart packaging provide a quick and easy to determine the product quality, thus, the aim of this study was to develop an ethylene biosensor used in smart packaging. The sensing reagent was composed of molybdenum (Mo) chromophore and palladium (Pd) on PVP/PVA/cellulose, and then immobilized on a surface modified LDPE. The effects of metal ions (e.g. tin or tungsten) on sensitivity / selectivity of sensor were also analyzed. Results showed that significant color development (ΔE) was noticed from Mo-Pd mix reagent in responding to 100 ppm/min ethylene stream for 30 min, while no interact with air. In the presence of 1mM metal ion including tin, tungsten, zinc, copper and iron in the reagent, ΔEs on the sensor were determined 2.3-8.8 as exposed to 50 ppm/min ethylene stream. Among metal ions added, tin ion showed a catalytic activity for color development, however, zinc and iron ions suppressed the reaction. Ethylene sensor prepared by molybdenum, palladium, tin ions mix (8:1:1) functioned to generate ΔE of 8.77 ± 1.55 exposed to 10 ppm ethylene atmosphere in 4 hr, which was significantly greater than in air (ΔE = 6.10 ± 0.94). Additionally, ΔEs were 18.41 ± 2.24 and 13.55 ± 1.63 in ethylene and control atmosphere, respectively. With greater ethylene exposure (25 ppm), ΔEs were 19.89 ± 1.58 and 14.94 ± 0.92 to ethylene and air for 4d, and 23.18 ± 1.05 and 17.45 ± 1.04 for 10d, respectively. Moreover, color development on sensor was found in association with extent of ethylene reaction, which was determined from residual ethylene in headspace by GC. In the selectivity test consisting of 10 ppm ethanol and/or acetic acid mixed with 10 ppm ethylene, the sensor primarily reacted ethylene for color development. An ethylene sensor made of multi-metal ions is capable of detecting ethylene in headspace by visible color development, and this is beneficial to indicate product quality. Keywords：ethylene, biosensor, metal ion, surface modified film

博士
國立臺灣大學
生化科技學系
104
An ethylene receptor gene named BoERS1 was cloned from a bamboo (Bambusa oldhamii) cDNA library. The open reading frame of BoERS1 was 1899 bp which encoded a 632-amino acid polypeptide. The encoded BoERS1 contained three domains, a sensor domain with three transmembrane regions, a GAF domain and a histidine kinase domain that contained all the conserved motifs (H, N, G1, F, and G2) that are present in the histidine kinases of the bacterial two-component systems and shared 90% sequence similarity with other ethylene receptors in plants such as rice or maize. According to real-time PCR analysis, the levels of BoERS1 mRNA in the shoots of field-grown bamboo were elevated along with the growth of the emerging shoots, especially in internodes and shoot meristems. Furthermore, the expression levels of BoERS1 were decreased under benzyladenine (BA, a cytokinin) and ABA treatments in multiple shoots of bamboo. The upstream sequences of BoERS1 were obtained using TAIL-PCR (thermal asymmetric interlaced polymerase chain reaction) and some cis-acting elements related to phytohormones, light, and dehydration were found. With in vitro kinase assay, the recombinant histidine kinase domain of BoERS1 (Ala 331 to Gly 611, BHK) showed autophosphorylation activity in the presence of Mn2+ and Mg2+, but not in the presence of Ca2+ and H2O. LC-ESI-MS/MS analysis indicated that four amino acid residues of BHK, namely Thr 442, Ser 444, Ser 489 and Ser 503, were phosphorylated by an in vitro kinase assay. Site-directed mutagenesis of these amino acids did not affect the phosphorylation activity of BHK. It indicated BHK was multiphosphorylated or had other phosphorylation residues. The model of BHK was built according to the structure of AtETR1 (PDB ID: 4PL9) and a histidine kinase of Thermotoga maritima (PDB ID: 2C2A). The three dimensional model of BHK had two flexible loops, namely L1 and L2. It is interesting to note that Ser 489 and Ser 503 were located in the both ends of L1 which was unique to the plant histidine kinase-containing enzymes and the phosphorylation may regulate the interactions between BoERS1 and other proteins; meanwhile L2 may be a gatekeeper of ATP binding pocket and regulate the entry of ATP. The identification of multiple phosphorylation sites on BoERS1 provides a new avenue for future structure–function studies of the ethylene receptor protein family.

碩士
國立臺灣大學
生物產業機電工程學研究所
100
A study of quartz crystal microbalance (QCM) modified by a silver ion (Ag+)-coordinated cellulose acetate (CA) membrane for ethylene (C2H4) monitoring is presented in this paper. Silver tetrafluoroborate (AgBF4) and cellulose acetate were dissolved in tetrahydrofuran (THF) and were spun on the surface of QCM to form the sensing membrane. Real-time detection of ethylene was carried out using the oscillator circuit and universal counter is used for data acquisition. A series of membranes with various weight percentage of AgBF4 to cellulose were fabricated and the sensitivity to ethylene was investigated. The linear dynamic range was 104 - 105ppm and the average response time was 40s. The limit of detection (LOD) is expected to be around 1000ppm, which is in the range for agricultural use.

碩士
國立臺灣大學
化學工程學研究所
88
An Au/Nafion electrode was fabricated by T-T method. Using an Au/Nafion electrode to develop an electrochemical sensor for detecting trace amount of ethylene. The basic properties of Au/Nafion regarding surface and electrochemical analyses were investigated and the electrochemical behavior of ethylene on Au/Nafion was also examined. The design of a gas circulation system simulating gaseous composition control in a plant cell suspension culture system was designed to facilitate the effect of gaseous composition on plant cell growth and secondary metabolites production. The T-T method with 0.05 M NaBH4 and 0.01 M HAuCl4 as reducing and gold solution gave active surface area of 375.48 cm2 and R.F. of 187.74. The electrochemical behavior and the crystal structure of Au deposited on Nafion were the same as pure gold metal. The sensitivity of ethylene sensor was dependent on gas flow rate and its response exhibited more stable up to 400 ml/min. The Au/Nafion electrode decayed gradually, dropped to 11.6 % after detecting 24 hours. The poison and potential shift resulted in electrode aging. The active surface area of ~370cm2 showed the best sensitivity. The oxidation of ethylene at Au surface was found to be: C2H4+H2O→CH3CHO+2H++2e- The depletion of ethylene on Au/Nafion electrode was lower than 1 %. The detection limit of Au/Nafion electrode system with active surface are of 375.48 cm2, applied potential 1.05 V (vs Ag/AgCl) and gas flow rate of 200 ml/min and 400 ml/min were 0.33 and 0.34 μA/ppm C2H4, respectively. On-line measurement of ethylene in a ethylene producing reactor was devised. An ethylene producing agent, ethephon was dissolved into a reactor to simulate a plant cell bioreactor. Time course accumulation of C2H4 in the headspace of reactor was measured by C2H4 sensor which was consistent with the gas chromatography analysis within the detection limit.

碩士
大同大學
生物工程學系(所)
102
The main purpose of this study by (ethylene - vinyl alcohol) polymer molecular template in the form of slurry preparation of thin film coated on a quartz crystal chip, combined with the quartz crystal microbalance sensors (QCM), making the caffeine molecule imprinted templates for detection of caffeine. In different molar proportions of (ethylene - vinyl alcohol )polymer of the polymerization (27mol%, 32mol%, 38 mol% and 44 mol%), mixed with caffeine for the bonding between the polymer. Then, after removed the caffeine, the template generation of holes for detection of caffeine, is called Molecular imprinted polymer, (MIP). Based on research results indicated that the 27 mol% concentrations of ethylene - vinyl alcohol caffeine molecule template preparation of polymer materials was the better choice. The optimal reaction time for caffeine MIP template and caffeine molecular was determined to be 30 min. The 27 mol% caffeine molecularly imprinted template incubated with different concentration of caffeine at 30 min, in the amount of QCM measurement frequency difference can reach 159.8Hz. There is a linear relationship between 2 ppm ~ 16 ppm concentrations of caffeine. The caffeine molecule templates can be reused six times its frequency variation remained at 90%. In the present study has been established (ethylene - vinyl alcohol) preparation techniques, combined with caffeine molecule templates QCM chips produced are initially developed can be applied to non-biological detection system to detect the caffeine.

碩士
義守大學
材料科學與工程學系碩士班
98
The multifunctionality of saliva is including anti-organisms, digestion and lubrication. Several salivary proteins are involving the digestion function in human body, they are also found as the biomarkers of pancreatic cancer. Pancreatic cancer and liver cancer are sometimes called “silent killer”, because no symptoms is observed. The molecularly imprinted polymers (MIPs) could be cheaper, stable and reusable sensing element of biosensors for the homecare system application. In this study, biocompatible polymers, poly(ethylene-co-ethylene alcohol), are employed for the imprinting of some proteins with digestion functions (e.g. amylase, lipase and lysozyme). Those proteins which exist in saliva are imprinted on EVAL and coated on a QCM chip for saliva measurement. The frequency changes are converted to the mass increased on the QCM chip to calculate the coverage of the QCM chip. Finally, the real saliva are collected, measured and compared with the examination by the commercial instrument ARCHITECT ci 8200 system.

The development of catalysts that selectively oligomerize light olefins for uses in polymers and fuels remains of interest to the petrochemical and materials industry. For this purpose, two tantalum compounds, (FI)TaMe2Cl2 and (FI)TaMe4, implementing a previously reported phenoxy-imine (FI) ligand framework, have been synthesized and characterized with NMR spectroscopy and X-ray crystallography. When tested for ethylene oligomerization catalysis, (FI)TaMe2Cl2 was found to dimerize ethylene when activated with Et2Zn or EtMgCl, and (FI)TaMe4 dimerized ethylene when activated with B(C6F5)3, both at room temperature.

碩士
國立高雄大學
化學工程及材料工程學系碩士班
102
Pesticides causing organisms resistant, harm environment and humans in Taiwan. In this study, using cyclic voltammetry and poly (ethylene-co-vinyl alcohol) electrodes detect two common pesticides ( chlorpyrifos and permethrin ). In 27mole% of poly(ethylene-co-vinyl alcohol) imprinting chlorpyrifos molecule efficiency up to 25.4, and 44 mole% of poly (ethylene-co-vinyl alcohol) imprinting permethrin molecule efficiency up to 21.3. Chlorpyrifos molecules film surface can be detected nitrogen from 1.88% before cleaning, after cleaning 0.00% to re-adsorption 0.27%. Permethrin molecules film surface can detect chlorine from 1.50% before cleaning , after cleaning 0.00% to re-adsorption 1.08%. Indicating that this sensor can re-adsorption pesticide molecules. In 0.15ppm to 1.5ppm concentration of chlorpyrifos and permethrin, the chlorpyrifos electrode sensors can sense the current from 144.60μA to 166.88μA. And permethrin electrode sensors from 30.00μA to 64.45μA. In 0.15ppm of chlorpyrifos and permethrin sample testing , the accuracy rate can reach 97%.