Browsing by Author "Senevirathne, S.A."

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    Assessment of the Omega-3 Fatty Acids Composition and Heavy Metals Content in Fish Oils in Sri Lankan Marine Fishes
    (Uva Wellassa University of Sri Lanka, 2021) Jayakody, J.A.K.S.; Senevirathne, S.A.; Senarathna, L.; Edirisinghe, E.M.R.K.B.
    The consumption of fish oil provides numerous speculated health benefits due to the presence of long chain omega-3 polyunsaturated fatty acids (PUFA). These health benefits may be challenged by the presence of heavy metals in fish oil. The objective of the present study was to compare the health benefits of omega-3 fatty acids and assess the risk of some heavy metals in fish oil extracted from marine fish. Sixteen species of fish were collected (n=3) from the Trincomalee fish market and fish oils were extracted using standard Bligh and Dyer method. Fatty acid composition of extracted fish oils were quantitatively determined by Gas Chromatography - Mass Spectrometry (GC-MS). The Arsenic (As), Cadmium (Cd) and Lead (Pb) contents were determined by using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS). The amount of fat present in fish varieties was varied over a wide range of 0.619% (Acanthocybium commersoni) to 8.626% (Carangoides fulvoguttatus). Among these species, the omega-3 content ranged from 7.814% - 31.818% of total fatty acids and the highest of omega-3 content was showed in Hemiramphus sp. (9.20 mg/100 g) and lowest level was reported in Auxis thazard (0.036 mg/100 g). In all species studied, Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) are the major omega-3 fatty acids and amounts of EPA and DHA have been exceeded 70% of the total omega-3 PUFAs. The content of As in extracted fish oils were ranged from 2.4353-18.3975 mg/kg in Nemapteryx caelata and Elagatis bipinnulata while Cd content were varied from 0.0262 - 1.2305 mg/kg in Scomberomorus commersoni and Nemapteryx caelata respectively. Platax sp. reported the lowest Pb content (0.467 mg/kg) while Acanthocybium commersoni reported the highest (2.282 mg/kg). Some of the fish oil samples had exceeded recommended human daily intake values of heavy metals, thus benefite of omega-3 fatty acids is challenged. Keywords: Fish oil; Omega-3 fatty acids; Heavy metals; GC-MS; ICP-MS
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    Comparative Study of Catalytic Reduction of Methylene Blue by Green Synthesized Copper Nanoparticles Using Syzygium cumini Leaves Extract
    (Uva Wellassa University of Sri Lanka, 2021) Sivirathne, S.M.S.W.; Senevirathne, S.A.; Jayaratna, N.B.
    Green synthesis using plant extracts is considered as an efficient, eco-friendly and inexpensive approach in metal nanoparticle synthesis. Copper nanoparticles are well known as catalysts in many organic reactions. The present study focuses on the green synthesis of heat and sunlight-induced copper nanoparticles using Syzygium cumini leaves aqueous extract as the source of reducing and capping agents. Synthesized nanoparticles were used to investigate and compare the catalytic effectiveness in the reduction reaction of Methylene Blue. The leaves extract was prepared by treating the leaves with distilled water at 50 °C for 1 hour. Copper nanoparticles were synthesized by mixing a known copper sulphate solution with leaves extract at a volume ratio of 5:3 followed by either heating (4 hours at 50 °C) or irradiating the mixture to sunlight for 4 hours. The synthesis of copper nanoparticles was initially recognized by the colour change of the extract solutions from pale yellow to dark brown. The formation of heat and sunlight derived copper nanoparticles were confirmed by UV-Visible peak maxima at 335 nm and 333 nm, respectively. Peak positions of Fourier transform infrared spectra of synthesized copper nanoparticles have revealed the activity of biomolecules as reducing and capping agents. Catalytic activities of synthesized copper nanoparticles were investigated using the reduction reaction of aqueous Methylene blue to Leucomethylene blue in the presence of excess NaBH4 as a model reaction. The reaction progress was monitored by UV– Visible spectrophotometry at room temperature. The apparent rate constants of the reaction in the presence of heat and sunlight derived copper nanoparticle catalysts were 51.1×10-3 min-1 and 32.6×10-3 min-1 respectively. The apparent rate constant of the reaction in the absence of copper nanoparticle catalyst was 8.1×10-3 min-1. The study confirms the catalytic activity of Syzygium cumini leaves derived copper nanoparticles while heat-induced copper nanoparticles showed 56% greater catalytic activity compared to sunlight-induced copper nanoparticles. Further characterization of nanoparticles and optimization of the biosynthesis parameters are needed to be performed. Keywords: Green synthesis; Dye degradation; Sunlight irradiation; Sustainability