Examinando por Materia "Espectrofotometría"

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    Determinación del SARS-CoV-2 en material particulado mediante método analítico por espectrofotometría ultravioleta visible (UV-VISIBLE): una revisión
    (2021-10-12) Montiel Murillo, Senis Beatríz; Paternina Uribe, Roberth de Jesús
    The coronavirus disease outbreak was first reported in Wuhan, China in late 2019 and early 2020. SARS-CoV-2 is a single-stranded RNA virus, the main cause of a serious respiratory disease called COVID-19, which is the cause of the current pandemic and which has spread rapidly in the human population. This review brings together the most relevant studies, carried out to date worldwide, which focus on knowing whether air pollution, especially particulate matter (PM2.5 and PM10), is considered a propitious transport agent for the virus, having taking into account that PM is identified as the main environmental cause of disease and premature death in the world, since it has a toxicity capacity that can increase by being able to absorb other substances such as polycyclic aromatic hydrocarbons (PAH), its heavy metals so that pathogens as long as they are below the radius of its diameter. Factor that affects the body's immunity, which makes people more vulnerable to contagions, therefore, it is important and crucial to elucidate the role of air pollution particles in the spread of the virus through a technique that is fast, accurate, versatile, easy to use and cost efficient like UV-visible spectroscopy. The method used to carry out this monograph was through a search, collection and bibliographic review of articles and scientific studies, graduate work, books, publications in scientific journals. Finding that there is a positive association between exposure to particulate matter and the presence of the virus. In addition, numerous studies highlight the potential links between exposure to air pollution and the severity of COVID-19, but there are very few investigative reports on the fast, accurate and economically viable diagnostic method such as UV-visible spectroscopy. Finally, according to the research carried out to date, they emphasize the importance of scientific studies to elucidate the role of air pollution particles in the spread of the virus and the performance of a technique for the sensitive and accurate detection of SARS-CoV viruses. -2 in the air.
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    Efecto del fotoperiodo sobre la producción de carotenoides y la morfología de la microalga Tetraselmis gracilis (Kylin)Butcher(1959).
    (2020-06-01) Pérez Cañas, Juan David; Gómez Montes, Yuliana; Arango Rivas, Carolina; Mogollón Arismendy, Martha
    Under normal conditions the microalgae are subject to periods of light / dark, and this alternation is generally also used in their cultivation. In this work, the effect of the photoperiod influence on the production of carotenoids and on the morphology of the microalgae Tetraselmis gracilis was evaluated, based on the biological method to determine population growth, the chemical method by spectrophotometry to estimate the concentration of carotenes and photographic record of cells for morphological measurements. The evaluation of population growth consisted of an experimental procedure, bioassay type, in which there were 3 experimental units each with 150 mL of F / 2 Guillard medium with 25% salinity, subjected to a photoperiod of 24: 0 and another 6 units which were maintained with a type of photoperiod 8:16 and 12:12, each with three replicates for a total of 9 units of each of the treatments, cell counts were performed each 48 hours in Neubauer chamber and variables of cell density, growth rate and doubling time were estimated, the determination of morphological changes was made by calculating cell volume. The photoperiod 24: 0 presented the highest cell density in growth with a value of 597958 cel / mL-1, the results of specific growth rate evidenced significant differences between treatments at 432 and 480 hours of culture, doubling times daily were on average very similar between treatments. The highest production of total carotenoids occurred when the microalgae was exposed to 8:16 photoperiod conditions in the exponential phase of growth, the 24: 0 treatment presented the highest values of cell volume as the phases of the experiment passed, in comparison to the other 2 photoperiods. The results showed that the photoperiod has a significant effect on the specific growth rate of Tetraselmis gracilis, as well as having a significant effect on the production of carotenoids. This study showed that T. gracilis, when exposed to variations in light intensity, that is, photoperiods, presents variations in growth, carotene content and cell volume, which serves as a basis for future research that has the object of study. massify its cultivation under controlled conditions for subsequent applications in various sectors of the industry.
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    Validación de un método analítico para la determinación de nitratos en agua natural y residual por espectrofotometría UV
    (Universidad de Córdoba, 2024-01-21) Petro Macea, Sayuri Elena; Lans Ceballos, Edineldo; Diaz Ponguta, Basilio; Burgos Galeano, Carlos Andrés
    El presente trabajo se realizó con el objetivo principal de validar un método analítico para la determinación de nitratos en aguas naturales y residuales mediante la espectrofotometría UV en el laboratorio de aguas de la Universidad de Córdoba según el método ultravioleta selectivo 4500- NO 3 B edición 24. Se hizo indispensable llevar a cabo la validación de este procedimiento analítico con el fin de presentar su adecuación con el propósito, de que el Laboratorio de Aguas de la Universidad de Córdoba pueda adquirir la acreditación de esta metodología, para que, en futuras investigaciones, estas tengan validez al ser publicadas. De esta manera, se lograría la generación de reconocimiento científico para el laboratorio, convirtiéndolo en un proveedor de servicios con un alto nivel de credibilidad a nivel departamental. Posteriormente se comprobó que los resultados obtenidos cumplieran con los criterios de aceptación dados por el standard methods, control de calidad analítica establecido por el laboratorio y cumplimiento de la norma NTC/ISO 17025:2017. Adicionalmente, el procedimiento efectuado para el análisis de nitratos, en aguas naturales y residuales consistió en la preparación de estándares con diferentes concentraciones a partir de una solución certificada de esta especie. Posteriormente para la medición de absorbancia de nitratos se tomaron estos estándares a diferentes concentraciones y, haciendo uso de un medio acido se llevó a cabo las lecturas en un espectrofotómetro de UV-VIS GENESYSTM 10s, a dos longitudes de onda a 220 y 275 nm para aguas naturales y residuales.