Química

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https://usc.scimago.es/handle/20.500.12421/91

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Degradación del Fluconazol mediante Foto-Fenton: Aplicaciones en la agroindustria
(Universidad Santiago de Cali, 2023) Martínez Sarria, Nicoll Andrea; Obeso Hurtado, Evelin Tatiana; Castro Narváez, Sandra Patricia (Directora)
Fluconazole (FCZ) is one of the most widely used fungicides to combat plant pathogens which has a Fluconazole (FCZ) is one of the most widely used fungicides to combat plant pathogens which has a low degradation rate making it an emerging contaminant. The monitoring of FCZ photooxidation by UV-vis spectroscopy under different conditions such as pH, wavelength, contaminant vs. hydrogen peroxide ratio (FCZ:H2O2) and concentration of ions such as iron (II), sulfate, carbonate and phosphate establish pseudo first order kinetics by graphical method with rate constant between 0.1796 to 0.0604 min-1 and half-life between 2.41 and 11.40 min, depending on pH, FCZ:H2O2 ratio and type of ion present in the sample. The addition of carbonate (200 mg/L) to the FCZ sample evidenced a removal rate higher than 99% in 25min at pH 2.0 and a 1:4 FCZ:H2O2 ratio. Gas chromatographic studies coupled to mass detector (GC-MS) establish the obtaining of low molecular weight by-products.
Empleo de melaza industrial en la síntesis de óxidos metálicos mixtos con potencial aplicación industrial
(Universidad Santiago de Cali, 2023) Castellanos Bernal, Cindy Vanessa; Morales Morales, Jimmy Alexander
In this work, lanthanum ferrite was prepared by mixing solutions of LaNO3•6H2O and Fe(NO3)3•9H2O with molasse and stirring continuously using a standard stirrer until a porous solid was obtained. It was macerated with agate mortar after being calcined in a muffle at various temperatures between 800 and 900ºC. This substance is placed in a vial for subsequent analysis using analytical methods like thermogravimetry (TGA), infrared vibrational spectroscopy (IR), and X-ray diffractometry (XRD). LaFeO3 nanoparticles measuring 89.2 nm were produced by employing ultrasound to aid in the synthesis and a 9-hour calcination period with a molasses/lanthanum ratio of 1.125. The increase in stated ratio and the shorter calcination time led to a larger crystallite size. The produced mixed metal oxide's electroconductive activity indicated how it might be used to catalyze important reactions, like the electrogeneration of oxygen.
Determinación de mercurio mediante análisis por espectroscopía de absorción atómica con vapor frío en aguas del río Palo en su paso por los municipios de Guachené y Puerto tejada
(Universidad Santiago de Cali, 2023) Viafara Ramos,Yancy Mayerly; Rios Acevedo, Jhon Jairo
The Palo river is located along the department of Cauca, one of the departments with the greatest legal and illegal mining exploitation, which is a topic of growing interest since the contamination of rivers due to the presence of mercury (Hg) is very critical, due to the bioaccumulation that prevents its elimination and the serious effects it has on human health and the deterioration of the environment. In this study, a method for quantification of Hg in raw water samples was validated by means of atomic absorption spectrometry with cold vapor; under the criteria of accuracy, precision, stability, linearity, detection and quantification limit and uncertainty, a working range of 0.805 ug/L Hg to 60 ug/L Hg was defined. Sampling was carried out in the Palo River at five (5) points of interest between the municipalities of Guachené and Puerto Tejada, in accordance with the mining activity reported in the area, and the mercury concentration was determined in three different seasons. Thus, Hg concentrations of between 0.2 and 2.0 μg/L were obtained at all sampling points, concluding that both mining and dredging activities as well as climate and hydrological conditions influence mercury concentration in the river studied.
Incidencia pos-cosecha en frutos de aguacate var. Hass frente a la aspersión de un bioestimulante foliar de silicio
(Universidad Santiago de Cali, 2023) Forero Rodríguez, Oswaldo; Castro Narváez, Sandra Patricia; Patiño, Oscar
The commercial and agroindustrial progress of avocado var. Hass in the country leads to the search for agronomic strategies to improve fruit quality, both in terms of shelf life and resistance to transport. This study establishes for the first time the impact of a silicon foliar fertilizer on Hass avocado crops. Incidence was evaluated by pre-harvest spraying and post-harvest fruit quality criteria. The addition of calcium silicate foliar fertilizer (Si: Ca ratio of 0.66) reduced the presence of free water in leaves, stems and fruit, which led to a decrease in the loss of weight and firmness of the fruit in postharvest storage. Likewise, a delay in the ripening process of the fruit was observed between one and two weeks with respect to the control. Physicochemical parameters such as increase in °brix, % titratable oleic acid and decrease in respiration rate with respect to CO2 and ethylene generation were found with the foliar treatment. The respiratory quotient (CR) in treated fruits are aerobic with carbohydrate consumption and in high dosages via fermentative anaerobic due to the creation of a silicon cuticle that decreases the respiratory processes. Photographic studies establish a 50% decrease of fruits in poor condition in week 5 of storage. The project benefits avocado farmers and also favors the commercialization of the fruit nationally and internationally by making the fruit less vulnerable to deterioration during transport. Likewise, the research opens new studies towards the determination of water stress in this avocado variety with and without the application of silicon-based stimulants.
Diseño del muestreo y caracterización fisicoquímica para la determinación de compuestos xenobióticos en el fruto de la piña (Ananás Comosus (L.) Merr) comercializadas en la ciudad de Santiago de Cali
(Universidad Santiago de Cali, 2023) Solarte Benavides, Diego Alexander; Gutiérrez Moreno, Nini Johanna; Peña Herrera, Juan Manuel
This Project presents the physicochemical results obtained from the sampling of pineapples sold in the city of Santiago de Cali, collected in different points of sale, for a subsequent study that will evaluate the presence of residual pesticides in the pineapple pulp. The determination of the physicochemical parameters of the fruit was carried out in accordance with the NTC 729-1 standard for fresh pineapple fruits, as well as the guidelines stipulated in the Codex Alimentarius, specifically in the CXS Standard 182-1993 for pineapples. The results show that the weight of the specimens for the honey gold pineapple is in the range between 1239,5g – 2051,6g, and for smooth cayenne it is in the range of 1572,4g – 1932,2g. The mature pineapples presented higher pH values: 3,78 for honey gold and 3.80 for smooth cayenne, while the medium ripe ones for honey gold a pH value of 3,61 and green pineapples with pH values of 3,52 and 3,64 for honey gold and smooth cayenne were obtained, respectively. The average ash percentage of the pulp was 0,11 to 0,37%, and the humidity was calculated in the range between 82,86 – 88,17%. The degrees Brix (°Brix) values indicated a higher sugar content and sensory maturity. For mature pineapples, 13,77 °Brix were obained, while medium ripe pineapples have a value of 10,35 °Brix and green pineapples have 7,78 °Brix. Regarding the percentage of acidity, an average value of 0,52% was obtained without variability between mature and moderately ripe pineapples, however, a value of 0,40% was obtained for green pineapple pulp. It is important to highlight between the conclusions that part of the physicochemical results are influenced by the state of maturity of the fruit. This project is the first part of a macroproject, in which the first phase will be the results of the physicochemical properties of pineapple samples sold in the city of Santiago de Cali, and subsequently a second phase with the study of identification of the agrotoxic compounds that would be present in the pulp of the fruit.
Espectroscopía en el Infrarrojo Cercano para la determinación de contaminantes Hídricos: “Revisión sistemática”
(Universidad Santiago de Cali, 2024) Gómez García, Valentina; Ríos Acevedo, Jhon Jairo
Near-infrared spectroscopy (NIRS) emerges as a promising method for large-scale tablet production due to its ability to collect multiparametric data quickly and accurately. However, despite the growing number of NIRS identification methods, only a few have been approved by regulatory authorities. This may be due to difficulties in clearly documenting these methods in official reports and audits. In another context, remote sensing of lakes in boreal and Arctic regions faces challenges due to high concentrations of organic matter, which significantly reduce reflectance signals in the visible part of the spectrum (400-700 nm). Similarly, in detecting organic compounds where reflectance is nearly null in the visible range due to absorption, peaks in the near-infrared spectrum (710 nm and 810 nm) become the primary detectable signals. Although the 710 nm peak has been used for over two decades to assess eutrophic waters, it has been demonstrated that the 810 nm peak is also useful for obtaining data on water constituents in seemingly clean water bodies, especially in lakes where the 710 nm peak is still affected by climatic and atmospheric conditions. These findings underscore the importance of adapting remote sensing methods to improve accuracy in complex aquatic environments
Cuantificación de sulfitos en las etapas de cocimiento y fermentación de cerveza y evaluación de su efecto sobre las propiedades sensoriales
(Universidad Santiago de Cali, 2024) Caicedo Roldan, Daly Dayanna; Tusso, Ricardo Andres; Agredo, William Alexander
This research addressed the low production of sulfites in the Corona brand of Cervecería del Valle, which resulted in non-compliance with the quality indicator known as the flavor stability index (FSI) and caused negative economic impacts. To resolve this situation, trials were conducted that modified parameters in the fermentation and brewing stages. The evaluated variables included the amount of ZnCl₂, which improved fermentation; the time and temperature of diacetyl release, which increased interaction with the yeast; and the amount of air injected into the wort, which elevated the concentration of SO₂. As a result, SO₂ values exceeding 3 ppm were obtained, acting as an antimicrobial and antioxidant agent that preserves the freshness of the beer. Additionally, FSI compliance was achieved at 95%, ensuring a high-quality product that meets consumer expectations and remains competitive in the market.
Aplicación de la espectroscopia de infrarrojo cercano (NIRS) en productos cárnicos
(Universidad Santiago de Cali, 2024) Rosero Martínez, José Miguel; Castro Narváez, Sandra Patricia (Directora)
An approximation is made to near infrared spectroscopy (NIRS) as a tool for evaluating the quality and authenticity of meat products. Given the growing demand for organic meat products and the need to guarantee their integrity, NIRS stands out as an effective alternative to traditional methods. The methodology employed included literature review, data analysis and method comparison, highlighting the importance of developing more robust calibration and standardization techniques. Quality parameters that NIRS can assess, such as moisture, fat, protein, color and pH, were identified, demonstrating its ability to provide rapid and non-destructive results. Comparison between NIRS and traditional techniques such as proximate analysis revealed that NIRS offers significant advantages in terms of speed and reduced need for sample preparation. However, limitations have been identified, including the need for specific calibrations for each type of meat and the dependence on the quality of the equipment used. Recommendations include advancing the development of calibration techniques and exploring the integration of NIRS technology in real-time computing environments.
Obtención de péptidos con potencial farmacológico a partir de hidrolisis enzimática in silico de la proteína de quinua con pepsina
(Universidad Santiago de Cali, 2024) Moreno Vivas, Valentina; Garcia Leon, Nathaly; Oñate Garzon, Jose Fernando
Peptides are protein fragments, whose amino acid sequence determines their structure and function, they have various biological functions and have antimicrobial, anticancer, antioxidant, anti-inflammatory activities, among others. They are obtained through enzymatic or acid hydrolysis processes that catalyze the breaking of peptide bonds, thus obtaining bioactive peptides used in various industries due to their ability to selectively interact with other molecules, being of interest in medical research for the development of new therapies. and diagnoses. Quinoa is a rich source of peptides that contain bioactive compounds beneficial for health. Performing peptide synthesis with enzymatic hydrolysis in vitro can be complex and expensive, requiring precision in the union of amino acids and with low yields. Cheaper alternatives, such as in silico enzymatic hydrolysis, have been developed using bioinformatics tools to predict bioactive peptides. In some studies, the pharmacological potential of peptides obtained from quinoa by in silico enzymatic hydrolysis has been evaluated. This approach could significantly impact the pharmaceutical industry, facilitating the development of new drugs for chronic diseases and improving quality of life. This implies an advance in scientific and technological knowledge, especially in the pharmaceutical industry
Desarrollo de una técnica miniaturizada para la determinación de nitrosaminas en productos cárnicos mediante HS-SPME-GC/MS
(Universidad Santiago de Cali, 2024) Gamboa Castillo, Miller Arbey; Ríos Acevedo, Jhon Jairo
Several studies have shown that the consumption of processed meat products is strongly linked to cancer associated with nitrosamines formed by the addition of nitrate or nitrite salts and certain amines. In this work, a method was developed for the determination of volatilenitrosamines in commercial sausages using headspace sampling by solid-phase microextraction and gas chromatography coupled to a mass spectrometer (HS-SPME-GC-MS). Two fused silica fibers were evaluated, one coated with polydimethylsiloxane (PDMS) and the other with carboxen/polydimethylsiloxane (CAR/PDMS). A fractional factorial design was employed to evaluate the influence of equilibrium time, ionic strength, extraction time, extraction temperature, and the addition of methanol on the extraction of Nnitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-butylamine (NDBA), and N-nitrosopiperidine (NPIP) in sausages. The method was validated and applied for the determination of nitrosamines in sausages, with linear ranges between 0-50 µg/L. The coefficients of determination for the calibration curves ranged from 0.9906 to 0.9976; the limits of quantification were between 0.254 and 0.389 µg/L. The precision and accuracy of the method were within the ranges of 2.7-7.3% and 70.286.4%, respectively. The implemented method proved to be simple, rapid, and exhibited adequate accuracy, sensitivity, and precision.
Caracterización fisicoquímica de tres aceites de cocina usados para freír diferentes alimentos y los respectivos biodiesel obtenidos por transesterificación en la ciudad santiago de cali, colombia.
(Universidad Santiago de Cali, 2024) Guerra Cuaran, Lina Alexandra; Bonilla Ramírez, Luis Fernando; Tusso, Ricardo Andrés; Zambrano Salgado, Yesid Fabián
The increase in global energy demand and the environmental concerns related to the use of fossil fuels, creates the need to find more sustainable alternatives, highlighting the relevance of biofuels to reduce dependence on oil. This study focuses on obtaining three types of biodiesel from Used Cooking Oils (UCO), from the frying of empanadas, fritters, breaded chicken and a new palm oil biodiesel used as a reference. Physicochemical tests were carried out to characterize the oils and biodiesel obtained to evaluate their potential as biofuel. Their yield was determined and 93.1% fritters, 87.5% empanadas and 90.6% breaded chicken were obtained. Based on the results of the characterization and their yield, it was determined that the biodiesel from the breaded chicken ACU has the greatest potential as biofuel and the biodiesel from the breaded chicken ACU proved to be the least suitable for such use.
Caracterización térmica y espectroscópica de sulfato de calcio dihidratado y sulfato de calcio hemihidratado
(Universidad Santiago de Cali, 2024) Correa Castaño, Leonel; Gutiérrez Moreno, Nini Johanna (Director); Castillo Gómez, Duván Fernando (Director)
The main objective of the present work was the thermal and spectroscopic characterization of calcium sulfate dihydrate and hemihydrate. Differential scanning calorimetry (DSC) and thermogravimetry (TGA) thermal analysis techniques were applied, finding characteristic peaks at 102 °C for the hemihydrate, 52.5 and 126.7 °C for the dihydrate. TGA showed a weight loss of 1.5% at 38.27 °C, 3% at 73.14 °C and 8.5% at 110 °C for the hemihydrate, the dihydrate showed weight losses of 17% at 56 °C, 31.6% at 110 ° C and 41.4% at 130 °C. Analysis by FT-IR revealed absorption bands between 3700 and 3500 cm-1 typical of the water molecules present and bands between 1200 and 900 cm-1 characteristic of the S=O double bond. The 20.72°, 23.38° and 29.14° for the dihydrate form. The determination of heavy metals by atomic absorption showed concentrations below 60 ppm in Na, Fe, Pb, As and Cd. The micrographs taken by SEM revealed the morphology of the crystals for the study compounds, exposing a varied number of sizes. It was found that the product has high purity, without the presence of anhydrites and low concentrations of metals such as Na, Fe, Pb, As and Cd.
Evaluación de calidad, infestaciones e identificación de componentes en cítricos mediante espectroscopia de infrarrojo cercano (NIRS)
(Universidad Santiago de Cali, 2024) Díaz Hurtado, Karol Lisbeth; Castro Narváez, Sandra Patricia
Near infrared spectroscopy (NIRS) has established itself as a crucial technology in modern agriculture, especially for citrus evaluation. This article reviewed and compared recent studies on the application of NIRS in citrus fruit quality assessment, infestation detection, and chemical component identification. The methodology employed includes the analysis of various NIRS techniques, such as reflectance and Fourier transform spectroscopy (FT-NIR), applied in different equipment and wavelength ranges. The results show that reflectance and FT-NIR techniques provide high accuracy in the evaluation of quality parameters such as soluble solids, titratable acidity, and fruit maturity and require methods validated by multivariate models. NIRS allows identification of pests not visible to the naked eye and in the determination of bioactive components such as flavonoids and organic acids, offering rapid and non-destructive evaluations, has the potential to optimize the citrus supply chain, improving product quality and facilitating real- time monitoring.
Aplicación del diseño de mezclas en la formulación de sidra de manzana
(2020) RAMÍREZ NARANJO; NATHALIA, SINISTERRA AMÚ; DIANA; Ramirez Navas; Juan Sebastian
Cider is a drink with very marked characteristics with respect to other spirits; It has abundant carbon dioxide, but produces less foam than a regular beer, acquires shades of yellow in transparent and bright appearance. (Drilleau, 2005). Cider. 2. The objective of this research was to evaluate the ratio of cider mixtures from three varieties of apple (Malus Domestica): Gala, Golden and Green.
Estudio de las interacciones del péptido Alyteserin 1C y de su análogo catiónico con modelos de membranas
(2019) Sanchez Arias; Kevin; Oñate Garzón; José Fernando
Antimicrobial peptides are part of the innate immunity of most living things and have antimicrobial activity against bacterium, viruses, fungi and parasites. Their cationic characteristics make them selective towards bacterial membranes with anionic surfaces.
Estudio electrocrómico de películas de óxido de molibdeno obtenidas por dip coating
(Universidad Santiago de Cali, 2020) Gómez Campo, David Alejandro; Castro Narváez; Sandra Patricia
Aspects related to the influence of acetic acid and hydrogen peroxide in the synthesis of xerosols from different sources of molybdenum (MoO3, (NH4)6Mo7O24.4H2O and Na2MoO4) for the Dip Coating deposition on conductive glass substrates of dioxide. Fluorine-doped tin (FTO) applicable in the construction of electrochromic energy conversion systems. The xerosols were characterized by IR-TF, TGA, DSC and voltammetric techniques that evidence the presence of crystalline systems with thermal treatment at temperatures above 176 °C, except for Na2MoO4 sources, with crystallization enthalpies of -0.047kJ/g. Xerosols are stable between 400-750 °C and films cannot be exposed to temperatures above 800 °C because they undergo thermal decomposition. The optical band gaps (Eg) of the films range between 3,282 eV and 3,810 eV with thicknesses between 736 and 1477 nm for MoO3 and (NH4)6Mo7O24.4H2O sources and for Na2MoO4 sources they present an average band gap of 3,899 eV. The electrochemical activation of the films consisting of potential step (-2.0 V to 2.0 V vs AgCl), in the presence of 1.0 M LiClO4 solution in PC established a color change in the light brown film with an increase in absorbance at 490 nm. Annealing films show yields of changes in transmittance between the light and dark state between 1.38 and 49.3%, coloring efficiencies () that range between 58.25 to 0.037 cm2 C-1 that are dependent on temperature and the type of xerosol used in the deposition. The use of acetic acid and hydrogen peroxide in the synthesis of xerosols imparts greater electrochromic efficiency to the films compared to those that not are treated.
Moluscos de el charco Nariño: una mirada desde la exploración bioquímica
(2020) Caicedo Perlaza, Yaneth Angelica; Nieto Ramírez, Luisa María; Pantoja Pulido, Kriss Dayana
Mollusks are non-segmented soft-bodied invertebrates protected by a shell and constitute the basis of the diet of many communities. Our objective was to determine the biochemical composition of two species of mollusks Littorina zebra (piacuil) and Anadara tuberculosa (piangua), which are an important nutritional source in El Charco, Nariño. In total, 30 samples of L. zebra with average sizes of approximately 3cm were collected, and 30 samples of A. tuberculosa differentiated by sex, identifying 13 females with average lengths of 8.4cm and 17 males with average lengths of 6.3cm.
Mejoramiento de la calidad de agua residual de una industria gráfica por método fisicoquímico y tratamiento Fotofenton
(Universidad Santiago de Cali, 2020) Castro Ordoñez, Oscar Eduardo; Morales Lame, Ronal Leonel; Castro Narváez, Sandra Patricia
Wastewater samples from flexographic printing machines of the graphic industry characterized by having high coloration, low pH, high oxygen demand and low biodegradability to primary physicochemical treatment followed by photofenton process with the objective of reducing chemical oxygen demand (COD). Initially, the pouring generator washing process was standardized, the primary treatment consisted of coagulation with aluminum polyhydroxychloride or ferric chloride, followed by filtration with activated carbon. The Fenton process was optimized by varying the pH, and the particles of iron and peroxide. The standardization of the washing process generated a 50% COD reduction, in the primary treatment, aluminum polyhydroxychloride was the best performance. After one hour of treatment with the photofenton process with UV lamp at pH: 4.0; 40.0 mgL-1 of Fe2+ and 200 mgL-1 of hydrogen peroxide, a 97% removal was processed. Thus, by coupling the physicochemical treatment with the photofenton process, the environmental impact of the wastewater of the graphic industry is reduced.
Caracterización fisicoquímica funcional del Almidón extraído de la papa china (Colocasia Esculenta) cultivada en el pacífico colombiano
(Universidad Santiago de Cali, 2019) Hurtado Herrera, Janer Guillermo; Castillo Ayala, Jorge Enrique
The evaluation of the physicochemical and functional properties of the starch extracted from the Chinese potato tubers (Colocasia esculenta) from the municipality of Timbiquí and López de micay – Cauca was carried out. The granules had particle size around (3.5-7.8 µm in diameter for sample 1 and 3.5-7.0 µm in diameter for sample 2); a high content of % amylose (67.6 and 70.7 respectively for M1 and M2) was found compared to other botanical sources, through the colorimetric method recommended by ISO 6647. The gelatinization temperatures were (78, 6 and 81.9 ° C, respectively) by heating a solution of the starch until a stable paste formed for a few seconds. The samples showed low water solubility (0.13 M1 and 0.23 M2 g / 100 mL) and a high water retention capacity (280.3 and 391.7% at 60 ° C) compared to 226% of the cassava and 162.8% for sago: which makes it a good quality starch. The gel pastes when subjected to a % processing of light at 650 nm in a Thermo Evo 201 UV spectrophotometer was (3.4 and 4.1%) respectively. Comparing these characteristics found in this tuber with other sources of starch commonly used in the industry, it is concluded that it can be used as a promising alternative in the food industry; In addition to having a high amylose content, it is a resistant starch, providing physiological health benefits.
Diseño, implementación y certificación del sistema de gestión de la calidad bajo los requisitos de la norma ntc-iso 9001:2015 para el laboratorio de ciencias básicas de la universidad Santiago de Cali
(Universidad Santiago de Cali, 2020) Pineda Quintero, Cindy Alejandra
The Laboratory of Basic Sciences, as part of its strategic development, decides to initiate the implementation and documentation of a Quality Management System under the requirements of the International Standard ISO 9001: 2015, with the objective of guaranteeing the continuous improvement of its processes, Increase customer satisfaction and be competitively located in the local and regional market by offering a timely service and ensuring the validity and traceability of the reported data. To establish a work route aimed at achieving certification, a work plan was defined that began with the diagnosis of the Laboratory in terms of compliance with standard requirements, for this, the entire existing document base was compiled. With the information obtained, the methodology based on the PHVA cycle was designed, which resulted in the study of the context of the Laboratory, the identification of the needs and expectations of the interested parties, the definition of the process quality objectives, the scope , the identification, evaluation, analysis and map of risks associated with the process, all this to finally structure the quality manual and facilitate the revision of the Quality Management System implemented, first by an internal quality audit that delivered a favorable concept for the presentation to external quality audit, which certified compliance with the requirements of the audited standard, ISO 9001: 2015, and granted the extension of the scope for the Subsystem to which the Basic Sciences Laboratory belongs.

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