Laminaria hyperborea as a Source of Valuable Glyceroglycolipids—A Characterization of Galactosyldiacilglycerols in Stipe and Blade by HPLC-MS/MS

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Determination of MEA-nitramine in Soil Water and Assessing the Sorption Potential of MEA-nitramine to Soil

Small amounts of amines are emitted with the flue gas from amine based carbon capture plants. The amines atmospheric degradation have been studied in detail. The environmental impact of the degradation products, e.g. the possibly carcinogenic and mutagenic nitramines, is however insufficiently studied. This thesis investigates the capacity of nitramines to sorb to soil, depending on the soils physiochemical characteristics. To accomplish this, the analytical challenges with regards to determination of nitramines in soil water had to be solved. Soil samples were collected in the vicinity of Technology Center Mongstad (TCM) (~15 km) as this is a possible future deposition site for nitramines. The sampling sites were chosen with the aim of collecting soils with different physiochemical properties, with special emphasis on the content of soil organic matter and soil texture. All of the collected soil samples (n=16) were analysed for explanatory parameters expected to influence soil sorption, such as organic matter (OM) content, dissolved natural organic matter (DNOM) leached from the soil, texture, mineralogy, pH and conductivity. A selection of the samples (n=5) were used in soil sorption experiments to assess the sorption potential of N-Nitroethanolamine (MEA-nitramine). A batch experimental set-up was used, and sorption was measured as loss of MEA-nitramine from the aqueous phase after being added at known concentrations (24 h equilibrium). For these samples, elemental composition was also determined. Possible correlations between the sorption coefficients and the soils physiochemical characteristics were assessed. Determination of MEA-nitramine in soil water with LC-MS/MS proved to be a challenge due to matrix effects. Different calibration methods with and without matrix matched calibration solutions were tested. Another nitramine, N-nitromethylamine (MMA-nitramine), was tested as internal standard. Additionally, a couple of sample pretreatment techniques were tested to try and separate the analyte from the matrix (solid phase extraction (SPE), filtration). Sorption partitioning coefficients between soil and aqueous phase were determined (Kd) and the results imply that a significant amount of MEA-nitramine will remain in the aqueous phase. Correlation between the partition coefficients for the five studied soils and the soils OM content was observed (r > 0.788). Loss of internal standard (MMA-nitramine) was also observed, this loss correlated strongly with the DNOM concentration in the sample supernatant (r = 0.9924), implying that sorption to DNOM could be important. The relation between sorption and OM content implies that sorption will generally be higher in the top soil (organic) horizons than in the lower (mineral) soil horizons. As deposition of atmospherically formed nitramines will be to the soil surface, this can serve to hinder mobility. The analytical determination method for nitramines in soil water was improved, although not considered satisfactory at the end of the study. Major improvement resulted from the used of matrix matched calibration curves, which compensate for both ion suppression/enhancement effects and possible sorption to DNOM. Even though this is time- and labour consuming, the method was proven more successful than attempts made to separate the analyte from the matrix prior to analysis. The used of MMA-nitramine as an internal standard for determination of MEA-nitramine was not successful, possibly due to the difference in retention time and therefore possible different effect from the matrix components. An isotope-labelled internal standard should therefore be acquired. Investigation into other sample pretreatments could also be of interest. Note that previously reported sorption partition coefficients for sorption of nitramines to soil could be inaccurate if matrix matched calibration curves were not employed

Identification of fatty acids in fractionated lipid extracts from Palmaria palmata, Alaria esculenta and Saccharina latissima by off-line SPE GC-MS

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Fatty Acid Profiles of Stipe and Blade from the Norwegian Brown Macroalgae Laminaria hyperborea with Special Reference to Acyl Glycerides, Polar Lipids, and Free Fatty Acids

A thorough analysis of the fatty acid profiles of stipe and blade from the kelp species Laminaria hyperborea is presented. Lipid extracts were fractionated into neutral lipids, free fatty acids, and polar lipids, prior to derivatization and GC-MS analysis. A total of 42 fatty acids were identified and quantified, including the n-3 fatty acids -linolenic acid, stearidonic acid, and eicosapentaenoic acid. The fatty acid amounts are higher in blade than in stipe (7.42 mg/g dry weight and 2.57 mg/g dry weight, resp.). The highest amounts of n-3 fatty acids are found within the neutral lipid fractions with 590.6 ug/g dry weight and 100.9 ug/g dry weight for blade and stipe, respectively. The amounts of polyunsaturated fatty acids are 3.4 times higher in blade than stipe. The blade had the highest PUFA/SFA ratio compared to stipe (1.02 versus 0.76) and the lowest n-6/n-3 ratio (0.8 versus 3.5). This study highlights the compositional differences between the lipid fractions of stipe and blade from L. hyperborea. The amount of polyunsaturated fatty acids compared to saturated- and monounsaturated fatty acids is known to influence human health. In the pharmaceutical, food, and feed industries, this can be of importance for production of different health products.publishedVersio

Identification of fatty acids in fractionated lipid extracts from Palmaria palmata, Alaria esculenta and Saccharina latissima by off-line SPE GC-MS

publishedVersio

Laminaria hyperborea as a Source of Valuable Glyceroglycolipids—A Characterization of Galactosyldiacilglycerols in Stipe and Blade by HPLC-MS/MS

Laminaria hyperborea (Gunnerus) Foslie 1885 is a seaweed native to the North Atlantic, which is utilized in the production of alginate. Its potential as a source of bioactive lipids remains unexplored. In this study, mono- and digalactosyldiacylglycerols (MGDG and DGDG) were identified in stipe and blade from L. hyperborea for the first time. Samples were harvested off the west coast of Norway in May 2018. Lipids were extracted with chloroform:methanol (2:1, v/v) and fractionated using solid phase extraction, whereupon the fatty acid content was determined by gas chromatography-mass spectrometry. The fatty acid profile was used to predict the mass of the glyceroglycolipids. A total of 103 and 161 molecular species of MGDG, and 66 and 136 molecular species of DGDG were identified in blade and stipe, respectively, by HPLC-ESI-MS/MS. The most abundant molecular species were identified from the total ion chromatograms. According to these, MGDG(20:5/18:4, 18:4/18:4, 16:0/18:1, 14:0/18:2, 14:0/18:1) and DGDG(20:5/18:4, 16:0/18:1, 14:0/18:1) were the most abundant in blade. On the other hand, in stipe, the most abundant molecular species were MGDG (14:0/18:2, 14:0/18:1, 16:0/18:1) and DGDG (14:0/18:1). The purpose of this study is to highlight the potential application of L. hyperborea in a biotechnological context