O uso intensivo do solo na agricultura associado ao consumo de fertilizantes nitrogenados tem causado a degradação acelerada dos recursos naturais e dos mananciais. A presente pesquisa teve como objetivo avaliar a lixiviação dos íons nitrato (NO3-) e amônio (NH4+) em colunas indeformadas de solo de uma pedossequência (cabeceira de drenagem), no município de Ponta Grossa, Paraná, analisando o comportamento dos solos em relação à susceptibilidade à contaminação da água pela lixiviação destes íons. Foram coletadas amostras de solo indeformadas de 0,5 m de comprimento, nas profundidades de 0 a 0,50 m e de 0,50 a 1,00 m. Nas amostras à granel foram efetuadas análises de macro e micronutrientes, da acidez atual e potencial, do teor de matéria orgânica e da granulometria nas camadas de 0-0,1 m, 0,1-0,2 m, 0,2-0,3 m, 0,3-0,5 m e 0,5-1,0 m de profundidade. Para determinação das porosidades (macro, micro e total) dos solos foram feitas coletas de amostras em anéis volumétricos nas mesmas profundidades das amostras à granel. Os solos descritos e amostrados foram os seguintes: Latossolo Bruno* Distrófico rubrico (não-hidromórfico), Cambissolo Húmico Distrófico gleissólico (semi-hidromórfico) e Gleissolo Melânico Tb Distrófico típico (hidromórfico). Nas colunas foram adicionadas quantidades de ureia e NPK equivalente a adubação recomendada para um ano e o volume de água adicionado foi equivalente a um ano de precipitação pluvial. Foram determinadas as concentrações de NO3- pelo método colorimétrico do salicilato e de NH4+ pelo sistema FIA (Análise de Injeção de Fluxo) nas amostras de água eluídas nos solos. Os resultados das análises foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade, utilizando o programa SAS. A partir dos resultados obtidos concluiu-se que: o volume de eluição para os solos da coluna de superfície foi maior para o Gleissolo e Latossolo em relação ao Cambissolo, provavelmente devido a compactação desse último. Ao contrário do solo das colunas de superfície, a subsuperfície do Cambissolo apresentou o maior volume de eluição em relação ao Latossolo; as colunas de solo de superfície apresentaram maior lixiviação de N-NH4+ e N-NO3- no Latossolo em relação ao Cambissolo e Gleissolo. Na subsuperfície, tanto a lixiviação de N-NH4+ como a lixiviação de N-NO3- não diferenciou estatisticamente no Latossolo e Cambissolo. Para o N-NH4+ houve maior retenção no Latossolo em relação ao Cambissolo e o Gleissolo na camada 0,0-0,1 m e maior retenção no Cambissolo e o Gleissolo na camada de 0,1-0,2 m; nas demais camadas não houve diferença estatística. Com relação ao N-NO3- praticamente não houve retenção nos solos estudados; a lixiviação de nitrogênio nos três solos foi maior na forma N-NH4+ em relação a forma N-NO3- / The intensive use of soil in agriculture associated with the nitrogen fertilizers consumption has caused accelerated degradation of natural resources and water sources. This study aimed to evaluate leaching of nitrate (NO3-) and ammonium (NH4+) ions in undisturbed soils columns of a pedossequence in the county of Ponta Grossa, Paraná (Brazil) (25o09\' S, 50o16\' W) and to analyse the behavior of soils in relation to water contamination susceptibility by leaching of these ions. Undisturbed soil columns were colleted in these soils, in the depths from 0 to 0.5 m and from 0.5 to 1.0 m. In the disturbed soil samples were measured both macro and micronutriens, current and potential acidity, organic matter contend and particle size at depths of 0-0.1 m, 0.1-0.2 m, 0.2-0.3 m, 0.3-0.5 m and 0.5-1.0 m. To determine the porosity (macro, micro and total) of soil, undisturbed soil samples were colleted using Uhland extractor at the same depths of the disturbed ones. Soils described and sampled were the following: Latosol (non-hydromorphic), Cambisol (semi-hydromorphic) and Gleisol (hydromorphic). Urea and NPK equivalent to fertilization for one year and water equivalent to one year of rainfall were added into the soil columns. Concentrations of NO3- and NH4+ in eluate (water) samples and in the soils were determined by salicylate colorimetric method and FIA system (Flow Injection Analysis), respectively. The results were subjected to variance analysis and means compared by Tukey test at 5% probability, using the SAS program. From this experiment it a could be concluded that: (i) the elution water volume for surface soil columns (0.0-0.5 m) was higher for Gleisol and Latosol in relation to Cambisol, probably due to compaction of Cambisol and, in contrast, for subsurface soil columns (0.5-1.0 m), the elution water volume was higher in Cambisol than Latosol; (ii) in surface soil columns, N-NH4+ and N-N0-3 lixiviations were higher in Latosol in relation to Cambisol and Gleisol and, in subsurface soil columns, both N-NH4+ and N-N0-3 lixiviations were not significantly different in Latosol and Cambisol; (iii) there was higher N-NH4+ retention in Latosol in relation to Cambisol and Gleisol only in 0.0-0.1 m soil layer and a higher N-NH4+ retention in Cambisol and Gleisol in relation to Latosol only in 0.1-0.2 m soil layer, whereas with respect to N-N03-, there was no retention in any soil layers in studied soils; (iv) nitorogen lixiviation in the three soils was higher as N-NH4+ than N-N0-3.

A new analytical technique to measure the chemical composition distribution (CCD) of polyolefins, crystallization elution fractionation (CEF), was introduced in 2006 during the First International Conference on Polyolefin Characterization. CEF is a faster and higher resolution alternative to the previous polyolefin CCD analytical techniques such as temperature rising elution fractionation (TREF) and crystallization elution fractionation (CRYSTAF) (Monrabal et al., 2007). Crystallization elution fractionation is a liquid chromatography technique used to determine the CCD of polyolefins by combining a new separation procedure, dynamic crystallization, and TREF. In a typical CEF experiment, a polymer solution is loaded in the CEF column at high temperature, the polymer is allowed to crystallize by lowering the solution temperature, and then the precipitated polymer is eluted by a solvent flowing through the column as the temperature is raised. CEF needs to be calibrated to provide quantitative CCD results. A CEF calibration curve consists of a mathematical relationship between elution temperature determined by CEF and comonomer fraction in the copolymer that could be estimated by Fourier transform infrared spectroscopy (FTIR) and carbon-13 nuclear magnetic resonance (13C NMR). Different comonomer types in ethylene/α-olefin copolymers will have distinct calibration curves. The main objective of this thesis is to obtain CEF calibration curves for several different ethylene/α-olefin copolymers and to investigate which factors influence these calibration curves. A series of homogeneous ethylene/α-olefin copolymers (1-hexene, 1-octene and 1-dodecene) with different comonomer fractions were synthesized under controlled conditions to create CEF calibration standards. Their average chemical compositions were determined by 13C NMR and FTIR and then used to establish CEF calibration curves relating elution temperature and comonomer molar fraction in the copolymer.

Aleutian mink disease virus (AMDV) causes significant loss to the mink industry in Nova Scotia (NS). Contaminated water is a speculated virus source therefore my objective was to develop a method for detection of AMDV in water samples. Initially, the quality and quantity of AMDV DNA extracted by four commercial kits was evaluated by PCR. Next, viral capture by adsorption-elution filtration was tested using spiked water samples. The 1MDS filter method was superior or comparable to the MgCl2 filter method and outperformed the AlCl3 method. Lastly, 16 watershed samples from Southwest NS and 11 samples from two AMDV-infected ranches were tested. Five ranch samples from the two ranches tested positive. Three samples, containing more than 22 virus copies/µL after concentration were quantifiable. Pre-concentration, these samples contained 16,787 to 33,471 virus copies/mL. In conclusion, although further optimization is required, a method for the detection of AMDV in water samples was developed.

A new analytical technique to measure the chemical composition distribution (CCD) of polyolefins, crystallization elution fractionation (CEF), was introduced in 2006 during the First International Conference on Polyolefin Characterization. CEF is a faster and higher resolution alternative to the previous polyolefin CCD analytical techniques such as temperature rising elution fractionation (TREF) and crystallization elution fractionation (CRYSTAF) (Monrabal et al., 2007). Crystallization elution fractionation is a liquid chromatography technique used to determine the CCD of polyolefins by combining a new separation procedure, dynamic crystallization, and TREF. In a typical CEF experiment, a polymer solution is loaded in the CEF column at high temperature, the polymer is allowed to crystallize by lowering the solution temperature, and then the precipitated polymer is eluted by a solvent flowing through the column as the temperature is raised. CEF needs to be calibrated to provide quantitative CCD results. A CEF calibration curve consists of a mathematical relationship between elution temperature determined by CEF and comonomer fraction in the copolymer that could be estimated by Fourier transform infrared spectroscopy (FTIR) and carbon-13 nuclear magnetic resonance (13C NMR). Different comonomer types in ethylene/α-olefin copolymers will have distinct calibration curves. The main objective of this thesis is to obtain CEF calibration curves for several different ethylene/α-olefin copolymers and to investigate which factors influence these calibration curves. A series of homogeneous ethylene/α-olefin copolymers (1-hexene, 1-octene and 1-dodecene) with different comonomer fractions were synthesized under controlled conditions to create CEF calibration standards. Their average chemical compositions were determined by 13C NMR and FTIR and then used to establish CEF calibration curves relating elution temperature and comonomer molar fraction in the copolymer.

1ABSTRACTCarbohydrate-deficient transferrin (CDT) is a biomarker for excessive and long-running intake of alcohol. It is a form of transferrin called disialotransferrin that under normal circumstances is <2 % of total transferrin in human blood. An increase is seen when alcohol consumption exceeds450 g per week. CDT is analyzed in serum usinghigh performance liquid chromatography (HPLC) and UV/VIS detection. The purpose of this study was to investigate if an “in routine” method could be improved by switching columns.With ion exchange chromatography transferrin glycoforms are separated and quantified. The carbohydrate-deficient transferrin glycoforms have an isoelectric point between 5,7-5,9 that depends on the number of sialic acids on the molecule. With the use of a salt gradient and pH above the isoelectric point the glycoforms can beseparated depending on their affinity to the stationary phase. Batches with patient and control serum was first analyzed on the routine column Source 15Q PE and then on the alternative column Reprospher 200 SAX 5μm.Student’s t-test showed that the two methods’results correlated but were significantly different. A Bland-Altman plot illustrated differences between the two columns. High and low control serum values from Reprospher were lower than the accepted interval. In this study Reprospher’s stationary phase seemed to be affected to such an extent that stabile retention time, better resolution, and stabile values could not be achieved and because the information about the column was lacking an attempt to regeneratethe columnwas not conducted.

La technique d’échantillonnage passif DGT (« Diffusive Gradients in Thin Films ») possède de nombreux avantages (intégration des variations temporelles, abaissement des limites de quantification) qui font d’elle une méthode prometteuse pour une utilisation en réseaux de mesure pour quantifier les éléments traces dans les eaux naturelles. Cependant, il existe encore des zones d’ombre qui constituent des freins à son utilisation dans un contexte réglementaire. Ce travail a donc pour objectif d’identifier des biais potentiels et ainsi contribuer à fiabiliser la méthode. Cette étude montre que l’obtention d’un résultat avec une incertitude minimisée doit passer par la détermination expérimentale des facteurs d’élution ; cependant, l’utilisation d’une valeur standard de 0,8 pour le Cr(III) et de 0,85 pour Al(III), Cd(II), Co(II), Cu(II), Ni(II), Pb(II) et Zn(II) est proposée afin d’alléger les manipulations tout en conservant une incertitude raisonnable (<10%). L’étude de l’influence de l’encrassement des dispositifs DGT a montré que la sorption des cations Cd(II), Cu(II) et Pb(II) sur les filtres encrassés affectent respectivement peu, modérément et fortement leur accumulation dans les échantillonneurs et donc leur quantification. Des durées d’exposition de moins d’une semaine sont alors préconisées pour ces éléments. En revanche, l’encrassement a eu un impact négligeable sur le Ni(II) et sur les oxyanions As(V), Cr(VI), Sb(V) et Se(VI). Enfin, une méthode de quantification simultanée du Cr(III), essentiel à la vie, et du Cr(VI), toxique, a été développée en vue d’améliorer l’évaluation de la toxicité d’une eau. Un unique échantillonneur DGT fixe les deux formes tandis qu’elles sont ensuite sélectivement séparées par une étape d’élution. Cette méthode est robuste sur une large gamme de forces ioniques et de concentrations en sulfate mais sur une gamme de pH plus restreinte ne couvrant pas toutes les eaux naturelles (4 à 6). / The passive sampling DGT technique (Diffusive Gradients in Thin Films) has a lot of benefits (time-weighted average concentrations, low limits of quantification) and would therefore be a useful tool for monitoring studies to quantify trace elements in natural water. However, there are still some limitations and grey areas that put the brakes on the development of the method for regulatory applications. The aim of this work is to identify potential biases and contribute to increase the method reliability. This study shows that a minimized uncertainty on results can be obtained only if elution factors are experimentally determined; however, standard values of 0.8 for Cr(III) and 0.85 for Al(III), Cd(II), Co(II), Cu(II), Ni(II), Pb(II) and Zn(II) are suggested to reduce manipulations while keeping reasonable uncertainty (<10%). Studying the influence of fouling developed on DGT devices showed that the sorption of cations Cd(II), Cu(II) and Pb(II) had, respectively, a slight, moderate and strong impact on their accumulation in DGT samplers and therefore on their quantification. Samplers should then be deployed for less than one week. In contrast, fouling had a negligible impact on oxyanions As(V), Cr(VI), Sb(V) and Se(VI). Finally, a method was developed to simultaneously quantify both Cr oxidation states naturally occurring in natural waters, which are Cr(III), essential to life, and Cr(VI), toxic. Both forms are accumulated in a single DGT sampler before being selectively separated during an elution step. This method is robust for wide ranges of ionic strengths and sulfate concentrations but for a narrower range of pH (4 to 6).

Magister Scientiae Dentium - MSc(Dent) / Resin filled dental composite materials has been introduced into dental practice since mid-1960s as an aesthetic restorative material for anterior teeth (Bowen, 1962 cited in Peutzfeldt, 1997). Since then, they have undergone several developments in order to enhance the longevity and performance of these materials. Resin filled dental composites consist of three main components namely, organic resin matrix which consists of a monomer, an initiator system and a stabilizer system, inorganic filler such as quartz, silica, etc. and coupling agent such as organo-silane coupling agent that chemically bonds the inorganic fillers to the organic resin matrix (Phillips, 1973). The properties and the performance of the resin filled dental composites are basically dependent upon the components of the materials. Some properties are related to the resin matrix, whereas others are related to the inorganic fillers and coupling agent. Furthermore, properties such as polymerization shrinkage and water sorption are dependent on both the inorganic fillers and the organic resin matrix (Asmussen, 1975; Hashinger and Fairhust, 1984; Munksgaard et al., 1987). Aim and objectives: The aim and the objectives of this study was to compare the water sorption and solubility of four bulk-fill dental resin composite materials namely, two conventional viscosity bulk-fill (Surefil bulk fill composite and Tetric N Ceram Bulk Fill) and two low viscosity bulk-fill flowable dental composite materials (Filtek Bulk Fill flowable restorative and Surefil SDR Flow). Materials and methods: Four types of bulk-fill composite restorative materials (2 bulk-fill conventional viscosity (Surefil bulk fill composite and Tetric N Ceram Bulk Fill) and 2 bulk-fill flowable low viscosity (Filtek Bulk Fill flowable restorative and Surefil SDR Flow) were used to analyse the water sorption and solubility for each resin composite type. Thirty specimens for each type of material were prepared, giving the total number of specimens to be 120 (n=120). To standardize this study Vita shade A2 was used for all the material types. All specimens were prepared in a Teflon mould with internal diameter of 15±1mm and thickness of 1±0.1mm in accordance with ISO 4049. The light curing unit used for all specimens was Elipar™ S10, (3M ESPE, Germany) at an output of 1200 mW/cm2 and used according to the manufacturer’s instructions. Prior to curing, the intensity of the light was checked using Cure Rite visible curing light meter (Caulk, USA) to ensure light output consistency between specimens and was found to be 1200 mW/cm2 . All the specimens were first removed from the Teflon mould as prepared and described previously and placed in an oven at 37 ºC until their weights were constant and these weights were recorded as m1 by using an analytic balance (OHAUS, TS400D, USA). Ten specimens of each type of resin filled composite were then immersed individually in glass containers filled with 10 ml distilled water and placed in the oven at 37±1 ºC for 24 hours, 7 days, 14 days respectively. The specimens were removed; surface water was blotted with tissue paper until free from visible moisture and weighed using the analytic balance (OHAUS, TS400D, USA). The resultant weights were recorded as m2. The specimens were then placed in a desiccator containing silica gel (Associated Chemical Enterprises, ZA) and freshly dried for two hours in an oven at 58 ºC and then weighted to obtain m3. According to Oysaed and Ruyter formula (Oysaed and Ruyter, 1986), the water sorption and solubility was calculated using the following equation: i.Water sorption (SP) = m2 -m3 / v., ii.Water solubility (SI) = m1 -m3 / v - where v is the volume of the specimen. For monomer leakage high performance liquid chromatography (HPLC) was used to identify monomers. The water that contained stored specimens was transferred to a refrigerator immediately after the specimens were removed until HPLC analysis was carried out to determine the amount of monomers that leached out of the cured composite specimens. Results: A significant difference between the materials (p<0.05, ANOVA Analysis of Variance) showed that Surefil SDR Flow composite had the lowest overall mean water sorption values (10.191) over the three time intervals (24 hrs, 7 days and 14 days) which was significantly smaller than the other means, followed by Filtek Bulk Fill flowable restorative composite (11.135) and Tetric N Ceram Bulk Fill composite (16.419). The highest water sorption mean value was recorded for Surefil bulk fill composite (21.515). The overall means of water solubility for the two bulk-fill flowables i.e. Filtek Bulk Fill flowable restorative and Surefil SDR Flow were smaller than bulk-fill conventional viscosity Surefil bulk fill and Tetric N Ceram Bulk Fill. However, all the test materials displayed no statistically significant increase in water solubility over the time period (p > 0.05 two way ANOVA test). The amounts of eluted monomers from bulk-fill conventional viscosity materials (Surefil bulk fill and Tetric N Ceram Bulk Fill) were higher than bulk-fill flowable materials (Surefil SDR Flow and Filtek Bulk Fill flowable restorative). Of all the monomers tested UDMA eluted more than Bis-GMA and TEGDMA. Overall UDMA monomer eluted the most, followed by Bis-GMA and the TEGDMA. Conclusion: Within the limitation of this study, the results of this study did not support the null hypothesis that there is no significant difference in the water sorption. The bulk-fill low viscosity flowables showed lower water sorption than the conventional viscosity bulk-fills. Surefil SDR Flow was significantly lower than the other materials followed by Filtek Bulk Fill flowable restorative and Tetric N-Ceram Bulk Fill and the highest overall means were recorded for Surefil bulk fill. For water solubility the overall means for the flowables of Filtek and SDR were smaller than Surefil and Tetric N-Ceram. For monomer elution three monomers were detected of which UDMA monomer eluted the most, followed by Bis-GMA and the TEGDMA. With regards to the elution of monomers, it was found that 3 monomers named UDMA eluted more than Bis-GMA and TEGDMA.

O uso intensivo do solo na agricultura associado ao consumo de fertilizantes nitrogenados tem causado a degradação acelerada dos recursos naturais e dos mananciais. A presente pesquisa teve como objetivo avaliar a lixiviação dos íons nitrato (NO3-) e amônio (NH4+) em colunas indeformadas de solo de uma pedossequência (cabeceira de drenagem), no município de Ponta Grossa, Paraná, analisando o comportamento dos solos em relação à susceptibilidade à contaminação da água pela lixiviação destes íons. Foram coletadas amostras de solo indeformadas de 0,5 m de comprimento, nas profundidades de 0 a 0,50 m e de 0,50 a 1,00 m. Nas amostras à granel foram efetuadas análises de macro e micronutrientes, da acidez atual e potencial, do teor de matéria orgânica e da granulometria nas camadas de 0-0,1 m, 0,1-0,2 m, 0,2-0,3 m, 0,3-0,5 m e 0,5-1,0 m de profundidade. Para determinação das porosidades (macro, micro e total) dos solos foram feitas coletas de amostras em anéis volumétricos nas mesmas profundidades das amostras à granel. Os solos descritos e amostrados foram os seguintes: Latossolo Bruno* Distrófico rubrico (não-hidromórfico), Cambissolo Húmico Distrófico gleissólico (semi-hidromórfico) e Gleissolo Melânico Tb Distrófico típico (hidromórfico). Nas colunas foram adicionadas quantidades de ureia e NPK equivalente a adubação recomendada para um ano e o volume de água adicionado foi equivalente a um ano de precipitação pluvial. Foram determinadas as concentrações de NO3- pelo método colorimétrico do salicilato e de NH4+ pelo sistema FIA (Análise de Injeção de Fluxo) nas amostras de água eluídas nos solos. Os resultados das análises foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade, utilizando o programa SAS. A partir dos resultados obtidos concluiu-se que: o volume de eluição para os solos da coluna de superfície foi maior para o Gleissolo e Latossolo em relação ao Cambissolo, provavelmente devido a compactação desse último. Ao contrário do solo das colunas de superfície, a subsuperfície do Cambissolo apresentou o maior volume de eluição em relação ao Latossolo; as colunas de solo de superfície apresentaram maior lixiviação de N-NH4+ e N-NO3- no Latossolo em relação ao Cambissolo e Gleissolo. Na subsuperfície, tanto a lixiviação de N-NH4+ como a lixiviação de N-NO3- não diferenciou estatisticamente no Latossolo e Cambissolo. Para o N-NH4+ houve maior retenção no Latossolo em relação ao Cambissolo e o Gleissolo na camada 0,0-0,1 m e maior retenção no Cambissolo e o Gleissolo na camada de 0,1-0,2 m; nas demais camadas não houve diferença estatística. Com relação ao N-NO3- praticamente não houve retenção nos solos estudados; a lixiviação de nitrogênio nos três solos foi maior na forma N-NH4+ em relação a forma N-NO3- / The intensive use of soil in agriculture associated with the nitrogen fertilizers consumption has caused accelerated degradation of natural resources and water sources. This study aimed to evaluate leaching of nitrate (NO3-) and ammonium (NH4+) ions in undisturbed soils columns of a pedossequence in the county of Ponta Grossa, Paraná (Brazil) (25o09\' S, 50o16\' W) and to analyse the behavior of soils in relation to water contamination susceptibility by leaching of these ions. Undisturbed soil columns were colleted in these soils, in the depths from 0 to 0.5 m and from 0.5 to 1.0 m. In the disturbed soil samples were measured both macro and micronutriens, current and potential acidity, organic matter contend and particle size at depths of 0-0.1 m, 0.1-0.2 m, 0.2-0.3 m, 0.3-0.5 m and 0.5-1.0 m. To determine the porosity (macro, micro and total) of soil, undisturbed soil samples were colleted using Uhland extractor at the same depths of the disturbed ones. Soils described and sampled were the following: Latosol (non-hydromorphic), Cambisol (semi-hydromorphic) and Gleisol (hydromorphic). Urea and NPK equivalent to fertilization for one year and water equivalent to one year of rainfall were added into the soil columns. Concentrations of NO3- and NH4+ in eluate (water) samples and in the soils were determined by salicylate colorimetric method and FIA system (Flow Injection Analysis), respectively. The results were subjected to variance analysis and means compared by Tukey test at 5% probability, using the SAS program. From this experiment it a could be concluded that: (i) the elution water volume for surface soil columns (0.0-0.5 m) was higher for Gleisol and Latosol in relation to Cambisol, probably due to compaction of Cambisol and, in contrast, for subsurface soil columns (0.5-1.0 m), the elution water volume was higher in Cambisol than Latosol; (ii) in surface soil columns, N-NH4+ and N-N0-3 lixiviations were higher in Latosol in relation to Cambisol and Gleisol and, in subsurface soil columns, both N-NH4+ and N-N0-3 lixiviations were not significantly different in Latosol and Cambisol; (iii) there was higher N-NH4+ retention in Latosol in relation to Cambisol and Gleisol only in 0.0-0.1 m soil layer and a higher N-NH4+ retention in Cambisol and Gleisol in relation to Latosol only in 0.1-0.2 m soil layer, whereas with respect to N-N03-, there was no retention in any soil layers in studied soils; (iv) nitorogen lixiviation in the three soils was higher as N-NH4+ than N-N0-3.

No description available.

The rapid growth of the biopharmaceutical industry has led to increasing demands on the protein production process. An important aspect is the yield of functional protein, which can be greatly affected by the choice of downstream purification. Purification based on acidic elution can be an issue for pH-sensitive proteins, since dramatic changes in pH can lead to protein aggregation and loss of function. The harsh, acidic elution conditions used in conventional purification of antibodies by Protein A affinity chromatography can thus be problematic. To address this, a calcium-dependent protein domain, called ZCa, has previously been developed for mild purification of antibodies, with elution close to physiological pH. Presented here are engineered variants of ZCa with novel affinity towards other biotherapeutics, which could also benefit from mild purification. Phage display selection, using a ZCa-based library, was applied to isolate promising ZCa-based binders against antigen-binding fragments, tissue plasminogen activator, and granulocyte colony stimulating factor, yet to be characterized. Additionally, three ZCa-based variants from a previous selection, with affinity for single-chain variable fragments (scFvs), have been identified and characterized. In a purification setup, they were shown to elute the scFv protein at neutral pH in a calcium-dependent manner. The reported results demonstrate that novel affinity can be introduced to the ZCa domain, while maintaining the calcium-dependent behavior that enables gentle purification. This offers a strategy for broadening the range of proteins that can be purified under mild conditions, with the benefit of reducing protein aggregation and thus increasing the yield of functional protein. / Den snabba tillväxten inom bioläkemedelsindustrin har lett till ökade krav på processen för proteinproduktion. En viktig aspekt är utbytet av funktionellt protein, där valet av reningsmetod kan ha stor påverkan. Proteinrening med syraeluering kan utgöra ett problem för pH-känsliga proteiner, då stora förändringar i pH kan leda till aggregering och försämrad funktionalitet. Det låga pH som används för eluering i den traditionella reningen av antikroppar med Protein A-baserad affinitetskromatografi kan därmed vara problematiskt. Som ett svar på detta har en kalciumberoende proteindomän, vid namn ZCa, tidigare utvecklats för mild rening av antikroppar med eluering nära fysiologiskt pH. I det här arbetet presenteras nya varianter av ZCa som modifierats för att binda till andra bioläkemedel, vilka också skulle kunna gynnas av mild proteinrening. Fagdisplay av ett ZCa-baserat bibliotek har applicerats för att isolera lovande ZCa-baserade bindare mot antikroppsfragment (Fab), vävnadsplasminogenaktivator och granulocytkolonistimulerande faktor, vilka ännu inte karaktäriserats. Utöver detta identifierades och karaktäriserades tre ZCa-baserade varianter från en tidigare selektion, med affinitet för enkelkedjiga antikroppsfragment (scFv). Då dessa varianter utvärderades för rening visade alla på kalciumberoende eluering av scFv vid neutralt pH. Det här demonstrerar att ny affinitet kan introduceras till ZCa-domänen, där det kalciumberoende beteende som möjliggör mild proteinrening bevaras. Detta erbjuder en strategi för att utöka antalet proteiner som kan renas under milda kalciumberoende förhållanden, vilket med fördel kan minska aggregering och därmed öka utbytet av funktionellt protein.