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Inspired by the easy intercalation of quinoxaline heterocyclic aromatic amines (HAAs) in double-stranded DNA (dsDNA), we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of an impedimetric chemosensor for the selective determination of a 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. HAAs are generated in meat and fish processed at high temperatures. They are considered to be potent hazardous carcinogens. The MIP film was prepared by potentiodynamic electropolymerization of a pre-polymerization complex of two adenine- and one thymine-substituted bis(2,2′-bithien-5-yl)methane functional monomer molecules with one 7,8-DiMeIQx template molecule, in the presence of the 2,4,5,2′,4′,5′-hexa(thiophene-2-yl)-3,3′-bithiophene cross-linking monomer, in solution. The as-formed MIP chemosensor allowed for the selective impedimetric determination of 7,8-DiMeIQx in the 47 to 400 μM linear dynamic concentration range with a limit of detection of 15.5 μM. The chemosensor was successfully applied for 7,8-DiMeIQx determination in the pork meat extract as a proof of concept.

In the global market era, food product control is very challenging. It is impossible to track and control all production and delivery chains not only for regular customers but also for the State Sanitary Inspections. Certified laboratories currently use accurate food safety and quality inspection methods. However, these methods are very laborious and costly. The present review highlights the need to develop fast, robust, and cost-effective analytical assays to determine food contamination. Application of the molecularly imprinted polymers (MIPs) as selective recognition units for chemosensors' fabrication was herein explored. MIPs enable fast and inexpensive electrochemical and optical transduction, significantly improving detectability, sensitivity, and selectivity. MIPs compromise durability of synthetic materials with a high affinity to target analytes and selectivity of molecular recognition. Imprinted molecular cavities, present in MIPs structure, are complementary to the target analyte molecules in terms of size, shape, and location of recognizing sites. They perfectly mimic natural molecular recognition. The present review article critically covers MIPs' applications in selective assays for a wide range of food products. Moreover, numerous potential applications of MIPs in the food industry, including sample pretreatment before analysis, removal of contaminants, or extraction of high-value ingredients, are discussed.

We investigated the effects of two metal salts, lithium trifluoromethanesulfonate (LiCF3SO3) and lithium bromide (LiBr), on the glass transition temperature (Tg) of poly(methyl methacrylate) (PMMA). Both LiCF3SO3 and LiBr greatly enhanced the Tg of PMMA under dry conditions. However, once the sample films were exposed to humidity, the PMMA containing LiCF3SO3 absorbed a large amount of water, which acts as a plasticizer. As a result, the Tg shifted to a lower temperature, which limits the utility of this polymer in industrial applications. In contrast, the Tg of PMMA containing LiBr was minimally affected by the absorption of water. This phenomenon can be explained by the ion–dipole interactions with the small number of dissociated lithium cations. Tg of PMMA was greatly enhanced by introducing ion–dipole interaction between lithium cations and carbonyl groups in PMMA as pseudo crosslinking points.

Quinoxaline heterocyclic aromatic amines (HAAs), are formed during meat and fish cooking, frying, or grilling at high temperatures. HAAs are classified as potent hazardous carcinogens, even though the HAAs are usually generated at very low concentrations (~ng per g of a food sample). This is because the HAA food contaminants effectively damage DNA by intercalation or strand break. Hence, chronic exposure to HAAs, even in low doses, can cause cancers of the lung, stomach, breast, etc. Currently, HPLC is used for the determination of these toxins in food matrices. However, this technique is expensive, tedious, and time-consuming. Therefore, fast, simple, inexpensive, and reliable HAAs determination procedures, without the need for separation of these toxins, in the protein food matrices are in demand. Molecularly imprinted polymers (MIPs) are excellent examples of bio-mimicking recognition materials. Therefore, they have found numerous applications in selective chemosensing. Within the present project, we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of an electrochemical sensor for selective DPV and capacitive detection and determination of 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. MIP-(7,8-DiMeIQx) film-coated electrodes were sensitive and selective to 7,8-DiMeIQx. The linear dynamic concentration range of the devised chemosensor extended from 12 µM to 0.4 mM 7,8-DiMeIQx and the imprinting factor was high, IF = 13. The present work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 711859. Scientific work was funded from the financial resources for science in the years 2017-2021 awarded by the Polish Ministry of Science and Higher Education for the implementation of an international co-financed project and National Science Centre Poland (grant No. NCN 2014/15/B/NZ7/01011 to W.K.)

Quinoxaline heterocyclic aromatic amines (HAAs), are formed during meat and fish cooking, frying or grilling at high temperatures. HAAs are classified as potent hazardous carcinogens, even though the HAAs are usually generated at very low concentration (~ng per g of a food sample). This is because the HAA food contaminants effectively damage DNA by intercalation or strand break. Hence, chronic exposure to HAAs, even in low doses, can cause cancers of lung, stomach, breast, etc. Currently, HPLC is used for determination of these toxins in food matrices. However, this technique is expensive, tedious, and time-consuming. Therefore, fast, simple, inexpensive, and reliable HAAs determination procedures, without need of separation of these toxins, in the protein food matrices are in demand. Molecularly imprinted polymers (MIPs) are excellent examples of bio-mimicking recognition materials. Therefore, they have found numerous applications in selective chemosensing. Within the present project, we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of a chemosensor for selective detection and determination of 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. MIP-(7,8-DiMeIQx)-film coated electrodes were sensitive and selective with respect to 7,8-DiMeIQx. The linear dynamic concentration range of the devised chemosensor extended from 12 µM to 0.4 mM 7,8-DiMeIQx and the imprinting factor was high, IF = 14. This work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 711859. Scientific work was funded from the financial resources for science in the years 2017-2021 awarded by the Polish Ministry of Science and Higher Education for the implementation of an international co-financed project and National Science Centre Poland (grant No. NCN 2014/15/B/NZ7/01011 to W.K.)

The effect of ion-dipole interaction between lithium cations and oxygen atoms in poly(methyl methacrylate) (PMMA), which leads to the great enhancement of glass transition temperature (Tg), on the linear viscoelastic properties is studied using binary blends of PMMA and lithium trifluoromethanesulfonate (LiCF3SO3). The strong interaction at low temperature leads to the high modulus in the glassy region even near Tg. The interaction becomes weak as increasing the temperature. Consequently, the rheological terminal region is clearly detected without a marked enhancement of steady-state compliance, although the zero-shear viscosity increases by the LiCF3SO3 addition. The result indicates that the crosslinking due to the ion-dipole interaction has a lifetime that decides the longest relaxation time. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2388–2394

Introduction: Poly(methyl methacrylate) (PMMA) has various attractive properties such as transparency, mechanical toughness, light weight and good weatherability [1]. Therefore, it is a candidate as a substitute for inorganic glass especially in the automobile industry due to high demand for a lightweight vehicle. In order to replace an inorganic glass, however, the thermal stability must be improved as it has a low glass transition temperature (Tg) (ca. 105 oC). Generally, the introduction of cross-linking and hydrogen bonding is known to enhance Tg of a polymer. Nevertheless, these methods have disadvantages such as losing thermoplastic nature. In this study, a salt with low lattice energy is mixed with PMMA by the solution blend technique. The salt used in this study is well mixed with PMMA and enhances the Tg without sacrificing the transparency and flowability of the material. Experiment: PMMA and 5 to 60 wt% of lithium trifluoromethanesulfonate (LiCF3SO3, LiFMS) or lithium perchlorate (LiClO4) were dissolved in the mixture solvent of dichloromethane (90 wt%) and methanol (10 wt%) and stirred for 1 hour. The solution was cast on the Teflon plate and dried at 160 ºC for 30 hours. The obtained mixtures were compressed into flat sheets with a thickness of 300 μm by a compression-molding machine for 3 min at 240 ºC under 10 MPa and subsequently cooled at 25 ºC. Tg of the samples was measured by using a dynamical mechanical analyzer and a differential scanning calorimeter. 3. Results and Discussion: Figure 1 shows Tg, measured by differential scanning calorimeter of the blends containing various amounts of the salts, in which the salt amount is expressed by the molar ratio of the lithium to the carbonyl group in PMMA. The result indicates that the salt addition greatly enhances Tg without scarifying its transparency. The Tg enhancement is presumably caused by the electrostatic interaction between Li-cation and carbonyl group in PMMA as indicated in attenuated total reflection results. As a result, the blends show high Tg. Moreover, all the blends are found to be transparent for PMMA/ LiFMS in the experimental range, while the blends with more than 50 wt% of LiClO4 are opaque. 4. Conclusion: The Tg enhancement of PMMA was observed by the addition of the lithium salts. Electrostatic interaction between lithium cation and the carbonyl group is responsible for the Tg enhancement., Supervisor:山口 政之, マテリアルサイエンス研究科, 修士, Contents Abstract i Acknowledgements ii Chapter 1 General Introduction 1 1.1 Amorphous polymer 1 1.2 Glass transition temperature of amorphous polymer 2 1.2.1 Williams-Landel-Ferry equation 3 1.2.2 Factor affecting Tg 6 1.2.3 Methods to enhance Tg 7 1.2.3.1 Addition of nanofiller 7 1.2.3.2 Cross-linking 8 1.3 Ionic interaction 9 1.3.1 Poly(electrolyte) 10 1.3.2 Ionomer 11 1.4 Processing method 14 1.4.1 Melt intercalation 14 1.4.2 Solution mixing 15 1.5 Objective 16 References 18 Contents v Chapter 2 PMMA Containing LiFMS 23 2.1 Introduction 23 2.2 Experimental 25 2.2.1 Materials 25 2.2.2 Method 25 2.2.3 Measurements 26 2.3 Results and Discussion 27 2.3.1 Transparency 27 2.3.2 Thermal properties 28 2.3.3 Functional group 31 2.3.2 Rheology 33 2.4 Conclusion 36 References 37 Chapter 3 Effect of cations and anions 39 3.1 Introduction 41 3.2 Experimental 41 3.2.1 Materials 42 3.2.2 Method 42 3.2.3 Measurements 42 3.3 Results and Discussion 44 Contents vi 3.3.1 Effect of molar ratio 44 3.3.2 Effect of anions 50 3.3.2.1 Halogens 50 3.3.2.1 Other salts 52 3.3.3 Effect of cations 55 3.3.3.1 Perchlorate 55 3.3.3.2 Trifluoromethane sulfonate 57 3.4 Conclusion 60 References 61 Chapter 4 Polar Polymers Containing Lithium Salt 63 4.1 Introduction 63 4.2 Experimental 65 4.2.1 Materials 65 4.2.2 Method 66 4.2.3 Measurements 68 4.3 Results and Discussion 69 4.3.1 Polystyrene 69 4.3.2 Polyamide 70 4.3.3 Poly(lactic acid) 71 4.3.4 Polyacrylonitrile 72 Contents vii 4.3.5 Poly(ethylene terephthalate-co-ethylene isophthalate) 73 4.4 Conclusion 77 References 78 Chapter 5 General Conclusion 80 Achievements 82

A molecularly imprinted polymer (MIP) film based electrochemical sensor for selective determination of tyramine was devised, fabricated, and tested. Tyramine is generated in smoked and fermented food products. Therefore, it may serve as a marker of the rottenness of these products. Importantly, intake of large amounts of tyramine by patients treated with monoamine oxidase (MAO) inhibitors may lead to a “cheese effect”, namely, a dangerous hypertensive crisis. The limit of detection at S/N = 3 of the chemosensor, in both differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) determinations, with the use of the Fe(CN)64-/Fe(CN)63- redox probe, was 159 and 168 µM tyramine, respectively. The linear dynamic concentration range was 290 µM to 2.64 mM tyramine. The chemosensor was highly selective with respect to the glucose, urea, and creatinine interferences. Its DPV determined apparent imprinting factor was 5.6. Moreover, the mechanism of the “gate effect” in the operation of the polymer film-coated electrodes was unraveled.