Technical optimization of the synthesis of flavours

The goal of this thesis is the investigation and optimization of the synthesis of potential fragrances. This work is projected as collaboration between the University of Applied Sciences in Merseburg and the company Miltitz Aromatics GmbH in Bitterfeld‐Wolfen (Germany). Flavoured compounds can be synthesized in different ways and by various methods. In this work, methods like the phase transfer catalysis and the Cope‐rearrangement were investigated and applied, for getting a high yield and quantity of the desired substances and without any by‐products or side reactions. This involved the study of syntheses with different process parameters such as temperature, solvent, pressure and reaction time. The main focus was on Cope‐rearrangement, which is a common method in the synthesis of new potential fragrance compounds. The substances synthesized in this work have a hepta‐1,5‐diene‐structure and that is why they can easily undergo this [3,3]‐sigma tropic rearrangement. The lead compound of all research was 2,5‐dimethyl‐2‐vinyl‐4‐hexenenitrile (Neronil). Neronil is synthesized by an alkylation of 2‐methyl‐3‐butenenitrile with prenylchloride under basic conditions in a phase‐transfer system. In this work the yield of isolated Neronil is improved from about 35% to 46% by according to the execution conditions of the reaction. Additionally the amount of side product was decreased. This synthesized hexenenitrile involved not only the aforementioned 1,5‐diene‐structure, but also a cyano group, that makes this structure a suitable base for the synthesis of new potential fragrance compounds. It was observed that Neronil can be transferred into 2,5‐dimethyl‐2‐vinyl‐4‐hexenoic acid by a hydrolysis under basic conditions. After five hours the acid can be obtained with a yield of 96%. The following esterification is realized with isobutanol to produce 2,5‐dimethyl‐2‐vinyl‐4‐hexenoic acid isobutyl ester with quantitative conversion. It was observed that the Neronil and the corresponding ester can be converted into the corresponding Cope‐product, with a conversion of 30 % and 80%. Implementing the Cope‐rearrangement, the acid was heated and an unexpected decarboxylated product is formed. To achieve the best verification of reaction development and structure, scrupulous analyses were done using GC‐MS, 1H‐NMR and 13C‐ NMR.

Numerical simulation of galvanized rebars pullout

The usage of rebars in construction is the most common method for reinforcing plain concrete and thus bridging the tensile stresses along the concrete crack surfaces. Usually design codes for modelling the bond behaviour of rebars and concrete suggest a local bond stress – slip relationship that comprises distinct reinforcement mechanisms, such as adhesion, friction and mechanical anchorage. In this work, numerical simulations of pullout tests were performed using the finite element method framework. The interaction between rebar and concrete was modelled using cohesive elements. Distinct local bond laws were used and compared with ones proposed by the Model Code 2010. Finally an attempt was made to model the geometry of the rebar ribs in conjunction with a material damaged plasticity model for concrete.

Consumers’ sensory acceptability of pork from immunocastrated male pigs

Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common method of controlling boar taint is surgical castration. However, immunocastration has been used in some parts of the world as an alternative to surgical castration. The aim of this study was to evaluate the sensory acceptability of meat from immunocastrated pigs (IM) compared with meat from females (FE), surgically castrated (CM) and entire males (EM). Twenty animals of each type were evaluated by 201 consumers in 20 sessions. Longissimus thoracis muscle of the different animals was cooked in an oven at 180 °C for 10 min. Consumers scored the odour and the flavour of the meat in a 9-point category scale without an intermediate level. There were no significant differences in consumer’s evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a higher percentage of dissatisfied scores and was significantly (P & 0.05) less accepted than meat from CM, IM and FE. Consumers’ acceptability of EM meat was always lower, independently of its androstenone levels. However meat with low levels of androstenone was more accepted that meat with medium or high levels of this substance. It can be concluded that immunocastration produced pork that was accepted by the consumers, and was indistinguishable from pork from CM or FE.

On making causal claims: A review and recommendations

Social scientists often estimate models from correlational data, where the independent variable has not been exogenously manipulated; they also make implicit or explicit causal claims based on these models. When can these claims be made? We answer this question by first discussing design and estimation conditions under which model estimates can be interpreted, using the randomized experiment as the gold standard. We show how endogeneity--which includes omitted variables, omitted selection, simultaneity, common methods bias, and measurement error--renders estimates causally uninterpretable. Second, we present methods that allow researchers to test causal claims in situations where randomization is not possible or when causal interpretation is confounded, including fixed-effects panel, sample selection, instrumental variable, regression discontinuity, and difference-in-differences models. Third, we take stock of the methodological rigor with which causal claims are being made in a social sciences discipline by reviewing a representative sample of 110 articles on leadership published in the previous 10 years in top-tier journals. Our key finding is that researchers fail to address at least 66 % and up to 90 % of design and estimation conditions that make causal claims invalid. We conclude by offering 10 suggestions on how to improve non-experimental research.

Les enjeux spatiaux et sociaux d'une dynamique interethnique en transition dans les quartiers de centre-ville. La construction des diverses formes de représentation dans la manière de définir un quartier de Nice.

Résumé Cette thèse de doctorat se fixe comme objectif général de définir la spécificité d'un espace urbain situé en centre-ville à travers sa dynamique sociale et interethnique. Il s'agit de relever les différentes formes et manifestations ethniques, mais également de comprendre la manière dont est vécue cette socialité, tout en tenant compte du contexte urbain dans lequel elles se situent. La particularité de ce travail est le fait de proposer une démarche alliant deux disciplines à savoir la géographie et la sociologie, dans le but de proposer une recherche transdisciplinaire, avec comme conséquence la mise en oeuvre d'une démarche commune nourrie des deux disciplines. Les quartiers ethniques situés en centre-ville ne se présentent pas comme des espaces figés, puisque des changements fréquents sont observés aussi bien au niveau de leur population que de l'affectation des locaux commerciaux et des logements. Ils semblent davantage se caractériser comme des « espaces à l'avenir indéterminé » dans le sens où leur avenir aussi bien au niveau de leur structure urbaine que de leurs rapports sociaux ne peut être prévisible et qu'ils sont par ailleurs susceptibles d'être soumis à de nombreux changements, d'où l'idée également d' « espaces en mutations ». Pour aborder ces thématiques de recherche, nous avons opté pour une étude fondée sur le principe de la représentation et de l'une des formes essentielles à travers lesquelles elles se produisent et se manifestent, à savoir les images. Cette recherche privilégie ainsi une analyse dynamique du phénomène interethnique, l'inscrivant dans le courant constructiviste qui s'intéresse notamment à l'étude des pratiques des acteurs sociaux et leurs représentations, dans le sens qu'elles sont le fruit d'une construction sociale. Dans ce type de démarche analytique, il s'agit de prendre en considération à la fois l'analyse du chercheur et la réalité objective et subjective du vécu des acteurs urbains qui regroupent les riverains, les commerçants, les membres associatifs, les politiques et les médias. C'est justement l'association de ces deux approches qui permet de définir un quartier urbain. Abstract "The spatial and social stakes of an interethnic dynamics in transition in the downtown area. The construction of the various forms of representations in order to define an urban quarter in Nice" The general objective of this PHD is to define the specificity of an urban space located in the downtown area with social and interethnic dynamics. Specifically the diverse ethnic form and sign to include the understanding mariner where society has lived in a specific urban context. The particularity of this work is to advance an analytic method using two disciplines: geography and sociology, in order to bring up a transdisciplinarian research with a common method. The ethnic quarters in the inner-city area are not presented as fixed spaces, since frequent changes were observed in the population level and at the allotment level of the commercial premises and the lodgings. Defined as "undetermined future spaces" as their future in the urban structure or the social relations can not be foresee and are supposed to be subjective to many changes. Therefore speaking of "mutations spaces". The option of this type of thematic research is the study of the principle of representation and essential form which shows and produces the images. Research promotes a dynamic analyses of the interethnic phenomena, inside the constructivist which is focused the practices of social actors, their own representations, and products of a social construction. The production of analytical approach is necessary in order to consider the analyses of the research worker and the objective and subjective reality of the life of the urban actors. It gathers the residents, tradesmen, members of associations, politicians and the press. The association of these types of approach define a urban quarter.

Estimation du débit de filtration glomérulaire par la formule DFG = K x T/Pcr [Estimation of glomerular filtration rate by the formula GFR = K x T/Pc].

BACKGROUND: Creatinine clearance is the most common method used to assess glomerular filtration rate (GFR). In children, GFR can also be estimated without urine collection, using the formula GFR (mL/min x 1.73 m2) = K x height [cm]/Pcr [mumol/L]), where Pcr represents the plasma creatinine concentration. K is usually calculated using creatinine clearance (Ccr) as an index of GFR. The aim of the present study was to evaluate the reliability of the formula, using the standard UV/P inulin clearance to calculate K. METHODS: Clearance data obtained in 200 patients (1 month to 23 years) during the years 1988-1994 were used to calculate the factor K as a function of age. Forty-four additional patients were studied prospectively in conditions of either hydropenia or water diuresis in order to evaluate the possible variation of K as a function of urine flow rate. RESULTS: When GFR was estimated by the standard inulin clearance, the calculated values of K was 39 (infants less than 6 months), 44 (1-2 years) and 47 (2-12 years). The correlation between the values of GFR, as estimated by the formula, and the values measured by the standard clearance of inulin was highly significant; the scatter of individual values was however substantial. When K was calculated using Ccr, the formula overestimated Cin at all urine flow rates. When calculated from Ccr, K varied as a function of urine flow rate (K = 50 at urine flow rates of 3.5 and K = 64 at urine flow rates of 8.5 mL/min x 1.73 m2). When calculated from Cin, in the same conditions, K remained constant with a value of 50. CONCLUSIONS: The formula GFR = K x H/Pcr can be used to estimate GFR. The scatter of values precludes however the use of the formula to estimate GFR in pathophysiological studies. The formula should only be used when K is calculated from Cin, and the plasma creatinine concentration is measured in well defined conditions of hydration.

On making causal claims: A review and recommendations

Social scientists often estimate models from correlational data, where the independent variable has not been exogenously manipulated; they also make implicit or explicit causal claims based on these models. When can these claims be made? We answer this question by first discussing design and estimation conditions under which model estimates can be interpreted, using the randomized experiment as the gold standard. We show how endogeneity--which includes omitted variables, omitted selection, simultaneity, common methods bias, and measurement error--renders estimates causally uninterpretable. Second, we present methods that allow researchers to test causal claims in situations where randomization is not possible or when causal interpretation is confounded, including fixed-effects panel, sample selection, instrumental variable, regression discontinuity, and difference-in-differences models. Third, we take stock of the methodological rigor with which causal claims are being made in a social sciences discipline by reviewing a representative sample of 110 articles on leadership published in the previous 10 years in top-tier journals. Our key finding is that researchers fail to address at least 66 % and up to 90 % of design and estimation conditions that make causal claims invalid. We conclude by offering 10 suggestions on how to improve non-experimental research.

Puupolttoaineiden kuivausmenetelmien kartoitus

Työssä kartoitetaan käytössä olevia pilkkeen ja hakkeen keinokuivausmenetelmiä. Lisäksi arvioidaan menetelmien energiankulutusta ja kustannuksia, sekä käydään läpi kuivaajan suunnittelussa huomioon otettavia seikkoja. Työn ohessa on tehty Excel-laskentataulukko, jonka avulla voidaan arvioida lämpöyrittäjyyden kannattavuutta koko tuotantoketju huomioon ottaen. Lopussa tutkitaan kolmen erityyppisen pilkekuivurin käyttöä ja arvioidaan laskentataulukon avulla niiden vaikutuksia pilkeyrittäjän talouteen. Yleisin puupolttoaineiden keinokuivausmenetelmä on kylmäilmakuivaus. Sääriippuvuudesta ja usein epätasaisesta kuivauslaadusta johtuen se soveltuu vain pienimuotoiseen ja sivutoimiseen polttoainetuotantoon. Lisälämmityksellä parannetaan ilman kuivauskykyä, jolloin kuivaus on nopeampaa, loppukosteudet alhaisempia ja vuotuinen käyttöaika pitempi. Lämmitysratkaisun valinta riippuu kuivurin halutusta vuotuisesta käyttöajasta ja tuotantomääristä. Ammattimaiseen ja ympärivuotiseen pilketuotantoon soveltuu parhaiten korkeita, 70 - 90 °C lämpötiloja käyttävä kuivuri. Korkealämpötila-kuivurissa on tärkeää huolehtia riittävästä eristyksestä ja säädellystä ilmanvaihdosta. Suurilla polttopuun tuotantomäärillä kuljetuskustannukset korostuvat. Samalla kasvaa markkinoinnin tarve. Mainonnassa voidaan hyödyntää tehokasta kuivausmenetelmää.

Ympäristöteknologioiden verifioinnin mahdollisuudet pilaantuneiden maiden laadukkaan käsittelyn edistämisessä

EU on käynnistämässä ympäristöteknologioiden verifiointijärjestelmää, jonka avulla voidaan tarjota käyttäjille ja sijoittajille riippumatonta tietoa innovatiivisten teknologioiden toimivuudesta ja suorituskyvystä ja parantaa niiden markkina-asemaa. Verifioinnilla tarkoitetaan kolmannen osapuolen suorittamaa prosessia tai mekanismia, jonka avulla tuotteen toiminta ja suorituskyky voidaan todentaa. Kansallinen ympäristöteknologioiden verifiointijärjestelmä on käytössä mm. Yhdysvalloissa ja Kanadassa. Euroopassa järjestelmä otettaneen käyttöön vuonna 2011–2012. Suomessa tehdään nykyisin noin 300 pilaantuneen maan puhdistushanketta koskevaa lupa- ja ilmoituspäätöstä vuosittain. Noin 85 prosentissa kohteista käytetään kunnostusmenetelmänä massanvaihtoa. Massanvaihto tulee ainakin toistaiseksi säilymään yleisimpänä kunnostusmenetelmänä, mutta mm. in situ -menetelmien käytön arvioidaan lisääntyvän. Tämän diplomityön tavoitteena oli arvioida voidaanko verifiointia hyödyntää pilaantuneiden maiden laadukkaan käsittelyn edistämisessä ja voiko verifiointi nopeuttaa innovatiivisten kunnostusmenetelmien markkinoillepääsyä. Aihetta tarkasteltiin mm. kahden erityyppisen pilaantuneen maan ja pohjaveden kunnostusmenetelmän, reaktiivisten seinämien (in situ) ja bitumistabiloinnin (ex situ) kautta. Pilaantuneiden maiden kunnostusmenetelmien toimivuus riippuu monista eri tekijöistä, joista osaa ei voida hallita tai mallintaa luotettavasti. Verifiointi soveltuukin parhaiten laitteiden tai PIMA-menetelmiä yksinkertaisempien puhdistusmenetelmien suorituskyvyn todentamiseen. Verifiointi saattaa kuitenkin hyvin toimia PIMA-kunnostuksen kohdalla esimerkiksi tiedollisena ohjauskeinona. Reaktiivisten seinämien ja bitumistabiloinnin verifioinnin työvaiheet ovat hyvin samankaltaiset, suurimpana erona seinämien kohdalla tulee kuvata myös kohde johon seinämä on asennettu. Reaktiivisten seinämien toiminta on riippuvaista monista ympäristötekijöistä, toisin kuin erillisellä laitteistolla suoritettavan bitumistabiloinnin. Tulosten perusteella voidaan yleistää, että verifiointi soveltuu paremmin ex situ -, kuin in situ -kunnostusmenetelmille.

Computational and Experimental Investigation of the Grooved Roll in Paper Machine Environment

In the paper machine, it is not a desired feature for the boundary layer flows in the fabric and the roll surfaces to travel into the closing nips, creating overpressure. In this thesis, the aerodynamic behavior of the grooved roll and smooth rolls is compared in order to understand the nip flow phenomena, which is the main reason why vacuum and grooved roll constructions are designed. A common method to remove the boundary layer flow from the closing nip is to use the vacuum roll construction. The downside of the use of vacuum rolls is high operational costs due to pressure losses in the vacuum roll shell. The deep grooved roll has the same goal, to create a pressure difference over the paper web and keep the paper attached to the roll or fabric surface in the drying pocket of the paper machine. A literature review revealed that the aerodynamic functionality of the grooved roll is not very well known. In this thesis, the aerodynamic functionality of the grooved roll in interaction with a permeable or impermeable wall is studied by varying the groove properties. Computational fluid dynamics simulations are utilized as the research tool. The simulations have been performed with commercial fluid dynamics software, ANSYS Fluent. Simulation results made with 3- and 2-dimensional fluid dynamics models are compared to laboratory scale measurements. The measurements have been made with a grooved roll simulator designed for the research. The variables in the comparison are the paper or fabric wrap angle, surface velocities, groove geometry and wall permeability. Present-day computational and modeling resources limit grooved roll fluid dynamics simulations in the paper machine scale. Based on the analysis of the aerodynamic functionality of the grooved roll, a grooved roll simulation tool is proposed. The smooth roll simulations show that the closing nip pressure does not depend on the length of boundary layer development. The surface velocity increase affects the pressure distribution in the closing and opening nips. The 3D grooved roll model reveals the aerodynamic functionality of the grooved roll. With the optimal groove size it is possible to avoid closing nip overpressure and keep the web attached to the fabric surface in the area of the wrap angle. The groove flow friction and minor losses play a different role when the wrap angle is changed. The proposed 2D grooved roll simulation tool is able to replicate the grooved aerodynamic behavior with reasonable accuracy. A small wrap angle predicts the pressure distribution correctly with the chosen approach for calculating the groove friction losses. With a large wrap angle, the groove friction loss shows too large pressure gradients, and the way of calculating the air flow friction losses in the groove has to be reconsidered. The aerodynamic functionality of the grooved roll is based on minor and viscous losses in the closing and opening nips as well as in the grooves. The proposed 2D grooved roll model is a simplification in order to reduce computational and modeling efforts. The simulation tool makes it possible to simulate complex paper machine constructions in the paper machine scale. In order to use the grooved roll as a replacement for the vacuum roll, the grooved roll properties have to be considered on the basis of the web handling application.

Fecal cortisol metabolites as indicators of stress in crab-eating-fox (Cerdocyoun thous) in captivity

Abstract: Blood samples collection is a common method in biological research using domestic animals. However, most blood sampling techniques are complicated and highly invasive and may therefore not be appropriate for wildlife animals in research concerning stress. Thus, a non-invasive method to measure steroid hormones is critically needed. The first goal of this study was to determine how glucocorticoids concentrations are impacted by translocation and reproductive activity in crab-eating-fox (Cerdocyoun thous) in captivity. The physiological relevance of fecal glucocorticoid metabolites was further validated by demonstrating: (1) The translocation of a male to a females enclosure resulted in a 3.5-fold increase compared to baseline concentrations, (2) changes in adrenocortical activity, as reflected in concentrations of fecal cortisol metabolites during reproduction, gestation and lactation in females foxes, indicating that social interactions resulted in large increases of fecal glucocorticoids metabolites during the reproductive season. From these findings we conclude that fecal samples can be used for the non-invasive assessment of adrenocortical status in crab-eating-fox.

Value at Risk in Foreign Exchange Risk Management

This thesis examines the suitability of VaR in foreign exchange rate risk management from the perspective of a European investor. The suitability of four different VaR models is evaluated in respect to have insight if VaR is a valuable tool in managing foreign exchange rate risk. The models evaluated are historical method, historical bootstrap method, variance-covariance method and Monte Carlo simulation. The data evaluated are divided into emerging and developed market currencies to have more intriguing analysis. The foreign exchange rate data in this thesis is from 31st January 2000 to 30th April 2014. The results show that the previously mentioned VaR models performance in foreign exchange risk management is not to be considered as a single tool in foreign exchange rate risk management. The variance-covariance method and Monte Carlo simulation performs poorest in both currency portfolios. Both historical methods performed better but should also be considered as an additional tool along with other more sophisticated analysis tools. A comparative study of VaR estimates and forward prices is also included in the thesis. The study reveals that regardless of the expensive hedging cost of emerging market currencies the risk captured by VaR is more expensive and thus FX forward hedging is recommended

Finding Methods for Recognizing and Classifying Spare Part Criticality – Case Full Deposit Stripping Machines

The aim of this Master’s thesis is to find a method for classifying spare part criticality in the case company. Several approaches exist for criticality classification of spare parts. The practical problem in this thesis is the lack of a generic analysis method for classifying spare parts of proprietary equipment of the case company. In order to find a classification method, a literature review of various analysis methods is required. The requirements of the case company also have to be recognized. This is achieved by consulting professionals in the company. The literature review states that the analytic hierarchy process (AHP) combined with decision tree models is a common method for classifying spare parts in academic literature. Most of the literature discusses spare part criticality in stock holding perspective. This is relevant perspective also for a customer orientated original equipment manufacturer (OEM), as the case company. A decision tree model is developed for classifying spare parts. The decision tree classifies spare parts into five criticality classes according to five criteria. The criteria are: safety risk, availability risk, functional criticality, predictability of failure and probability of failure. The criticality classes describe the level of criticality from non-critical to highly critical. The method is verified for classifying spare parts of a full deposit stripping machine. The classification can be utilized as a generic model for recognizing critical spare parts of other similar equipment, according to which spare part recommendations can be created. Purchase price of an item and equipment criticality were found to have no effect on spare part criticality in this context. Decision tree is recognized as the most suitable method for classifying spare part criticality in the company.

Sydämen eteisvärinän tunnistaminen matkapuhelimen kiihtyvyysanturilla

Yli 140 miljoonaa ihmistä kärsii kroonisesta eteisvärinästä. Monilla ihmisillä on eteisvärinää, vaikkeivat siitä itse tiedä. Hoito on yksinkertainen, mutta hoidon piiriin eivät päädy kaikki yksinkertaisten seulontamenettelyjen tuloksena. Elektrokardiogrammi (EKG) sydämen toimintojen tunnistusmenetelmänä on tällä hetkellä yleisin vaihtoehto eteisvärinän seulontaan. EKG-laitteet ovat arvokkaita ja haasteellisia yksittäisen käyttäjän arkielämän kannalta. Vaihtoehtoinen sydämen monitorointimenetelmä on ballistokardiografinen (BKG) mittaus. EKG:n ja BKG:n ominaisia piirteitä käydään lävitse ja vertaillaan vahvuuksia sekä heikkouksia näiden kahden mittausmenetelmän välillä. BKG:ta on tutkittu jo pitkään, mutta mittaukseen soveltuvia tähän käyttökohteeseen varsinaisesti suunniteltuja laitteita ei ole paljoakaan tuotteistettu markkinoille asti. Työssä tutkitaan matkapuhelimen kiihtyvyysanturin soveltuvuutta BKG-mittauksen suorittamiseen. Tällä menetelmällä on mahdollista tuoda helposti sydänmonitori lähelle ihmisiä ja jokainen voi omalla matkapuhelimellaan tarkkailla sydämensä toimintaa. Diplomityössä selvitetään erilaisten markkinoilla olevien mobiililaitteiden soveltuvuutta kiihtyvyysanturitutkimukseen. Useampaa mallia koskevan selvitystyön tuloksena valitaan parhaiten toimiva vaihtoehto, jolla jatketaan tutkimusta suunnittelemalla mittausprosessi. Ensimmäisen vaiheen mittauksissa valitaan 20 perustervettä koehenkilöä tutkimukseen. Tutkimuksen tuloksena saadaan tutkimushypoteesin mukainen tulos ja sydämen lyönnit saadaan tunnistettua kaikilla koehenkilöillä. Ensimmäisen vaiheen aikana suoritetaan myös liikehäiriötutkimusta. Tässä suoritetaan yksinkertaiset käden, jalan ja pään liikkeiden vaikutuksen arvioinnit kiihtyvyysanturisignaaliin. Lisäksi selvitetään, miten puhuminen mittauksen aikana välittyy tutkimuslaitteeseen ja suoritetaan arvio siitä, miten tämä voidaan ottaa huomioon. Ensimmäisen vaiheen havaintojen perusteella jatkokehitetään mittausprosessia ja pyritään optimoimaan tätä, jotta laajempi otosjoukko on mahdollista saavuttaa mahdollisimman vähän aikaresursseja kuluttaen. Työssä valmistellaan laajemman, 1000 koehenkilöä sisältävän, toisen tutkimusvaiheen suoritusta. Diplomityön osana valmistellaan Varsinais-Suomen Sairaanhoitopiirin eettiselle toimikunnalle lausuntohakemus tutkimukselle. Hakemuksessa käsitellään laajasti tutkimuksen suorittamista eri osa-alueilla. Toisen vaiheen tuloksen noudattaessa tutkimushypoteesia, voidaan todeta matkapuhelimen kiihtyvyysanturin olevan soveluva menetelmä sydämen toiminnan tutkimiseen.

Gas chromatographic electron capture negative ionization mass spectrometric (GC/ECNI/MS) determination of unique fluorinated compounds in the sediments of Lake Ontario and the effect of high-boiling alcohols (as injection solvents) on chromatographic behaviour of polycyclic aromatic hydrocarbons in gas chromatography

Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of previously deposited contaminated sediments, and probable continued leaching from the dumpsite. Part II - Polycyclic Aromatic Hydrocarbons Gas chromatography/mass spectrometry is the most common method for the determination of polycyclic aromatic hydrocarbons (PAHs) from various matrices. Mass discrimination of high-boiling compounds in gas chromatographic methods is well known. The use of high-boiling injection solvents shows substantial increase in the response of late-eluting peaks. These solvents have an increased efficiently in the transfer of solutes from the injector to the analytical column. The effect of I-butanol, I-pentanol, cyclopentanol, I-hexanol, toluene and n-octane, as injection solvents, was studied. Higher-boiling solvents yield increased response for all PAHs. I -Hexanol is the best solvent, in terms of P AH response, but in this solvent P AHs were more susceptible to chromatographic problems such as peak splitting and tailing. Toluene was found to be the most forgiving solvent in terms of peak symmetry and response. It offered the smallest discrepancies in response, and symmetry over a wide range of initial column temperatures.