USC Repository :: Browsing by Author "Rosero Moreano, Milton"

Browsing by Author "Rosero Moreano, Milton"

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Alternative Ecosorbent for the Determination of Trihalomethanes in Aqueous Samples in SPME Mode
(2022-12) Sánchez Duque, Gustavo; Lozada Castro, Juan José; Hara, Emerson Luis Yoshio; Grassi, Marco Tadeu; Rosero Moreano, Milton; Ríos Acevedo, Jhon Jairo
A new sorbent material based on modified clay with ionic liquid immobilized into an agarose film was developed as part of this study. It was applied to determine organochlorine pollutants, like disinfection byproducts, through headspace solid-phase microextraction-gas chromatography-electron capture detection (HS-SPME-GC-ECD). The disinfection byproducts determined in this study were used as model molecules because they were volatile compounds, with proven severe effects on human health. Their presence in aquatic environments is in trace concentrations (from pg L−1 to mg L−1). They are classified as emergent pollutants and their determination is a challenge for analytical chemists. The parameters which affected the extraction efficiency, i.e., number and distance between SPME discs, salt concentration, the temperature of extraction, extraction time, and desorption time, were optimized. A wide linear dynamic range of 10–1000 ng mL−1 and coefficients of determination better than 0.997 were achieved. The limits of detection and the limits of quantitation were found in the ranges of (1.7–3.7) ng mL−1 and (5.6–9.9) ng mL−1, respectively. The precision, expressed as relative standard deviation (RSD), was better than 8%. The developed sorbent exhibits good adsorption affinity. The applicability of the proposed methodology for the analysis of trihalomethanes in environmental and water samples showed recoveries in the range of 86–95%. Finally, the newly created method fully complied with the principles of green chemistry. Due to the fact that the sorbent holder was made of agarose, which is a wholly biodegradable material, sorbent clay is a widespread material in nature. Moreover, the reagents intercalated into the montmorillonite are new green solvents, and during the whole procedure, low amounts of organic solvents were used.
Green method to determine triazine pesticides in water using Rotating Disk Sorptive Extraction (RDSE)
(2021) Velasco, Edouard; Ríos Acevedo, Jhon Jairo; Sarria Villa, Rodrigo; Rosero Moreano, Milton
The following work presents the development of the solid phase extraction technique with rotary disk (RDSE) in which the analysis for seven triazines in surface waters was first implemented. All the variables involved in extraction have been studied and optimized using a solid phase of octadecyl (C18) deposited on surface of the disk. Triazines were analyzed quantitatively by gas chromatography with simple quadruple mass detector, recoveries obtained for seven triazines were between 80% and 120%, accuracy expressed as RSD was between 3.21% and 6.34%, and detection limit of the method was between 0.020-0.056 μgL-1 according to each analyte, which indicates a good reproducibility and precision of the method. Finally, the method was applied to analyze the objective compounds in water samples obtained in the Bolo River (Palmira-Colombia), in which triazines were not detected
New solid phase microextraction fibers with green clay coating via radio frequency magnetron sputtering for detecting low-polar compounds in water samples
(2024-12-15) Fiscal Ladino, Jhon; Lozada Castro, Juan Jose; Rios Acevedo, Jhon Jairo; Montaño Montoya, Diego; Carasek, Eduardo; Richter, Pablo; Pulzara Mora, Alvaro; Martínez, Liliana Moncayo; Rosero Moreano, Milton
Background Developing highly sensitive and selective measurement techniques to detect trace compounds in diverse matrices is a significant challenge in analytical chemistry. These techniques must adhere to green chemistry principles by minimizing organic solvent use, simplifying sample preparation, and streamlining process steps. Additionally, there is a growing need for sustainable analytical methods due to increased environmental awareness. The problem addressed in this work is the need for an eco-friendly and efficient method for the extraction and detection of trace organochlorine pesticides in water samples. Results We employed SPME using a novel clay thin film sorbent, deposited on a nickel-titanium alloy wire via magnetron sputtering. Montmorillonite clay was chosen for its excellent adsorption properties and eco-friendly nature, aligning with green chemistry principles. The approach involved coating the SPME fiber with hydrophobic modified montmorillonite clay, followed by silylation. The method was tested for extracting 12 model organochlorine pesticides, including BHC, lindane, and DDT, demonstrating high isolation efficiency. The coated thin film and its silylation modification were characterized using standard spectroscopic techniques, confirming the successful creation of a new adsorbent phase. The direct immersion SPME approach achieved relative recoveries ranging from 65 % to 99 %, with reproducibility (RSD) below 6 %. This method provided low detection limits (10–15 ng L−1) and quantitation limits (32–50 ng L−1). Significance Our approach offers an eco-friendly, highly efficient solution for the extraction and detection of trace organochlorine pesticides. The significant improvement in recovery rates and reproducibility, combined with low detection and quantitation limits, underscores the potential of this method to enhance analytical practices in environmental monitoring and public health. Furthermore, the use of sustainable materials and processes aligns with global efforts to reduce environmental impact in analytical chemistry.
New solid phase microextraction fibers with green clay coating via radio frequency magnetron sputtering for detecting low-polar compounds in water samples
(Elsevier B.V., 2024) Fiscal Ladino, Jhon; Lozada Castro, Juan Jose; Rios Acevedo, Jhon Jairo; Montaño Montoya, Diego; Carasek, Eduardo; Richter, Pablo; Pulzara Mora, Alvaro; Martínez, Liliana Moncayo; Rosero Moreano, Milton
Background: Developing highly sensitive and selective measurement techniques to detect trace compounds in diverse matrices is a significant challenge in analytical chemistry. These techniques must adhere to green chemistry principles by minimizing organic solvent use, simplifying sample preparation, and streamlining process steps. Additionally, there is a growing need for sustainable analytical methods due to increased environmental awareness. The problem addressed in this work is the need for an eco-friendly and efficient method for the extraction and detection of trace organochlorine pesticides in water samples. Results: We employed SPME using a novel clay thin film sorbent, deposited on a nickel-titanium alloy wire via magnetron sputtering. Montmorillonite clay was chosen for its excellent adsorption properties and eco-friendly nature, aligning with green chemistry principles. The approach involved coating the SPME fiber with hydrophobic modified montmorillonite clay, followed by silylation. The method was tested for extracting 12 model organochlorine pesticides, including BHC, lindane, and DDT, demonstrating high isolation efficiency. The coated thin film and its silylation modification were characterized using standard spectroscopic techniques, confirming the successful creation of a new adsorbent phase. The direct immersion SPME approach achieved relative recoveries ranging from 65 % to 99 %, with reproducibility (RSD) below 6 %. This method provided low detection limits (10–15 ng L−1) and quantitation limits (32–50 ng L−1). Significance: Our approach offers an eco-friendly, highly efficient solution for the extraction and detection of trace organochlorine pesticides. The significant improvement in recovery rates and reproducibility, combined with low detection and quantitation limits, underscores the potential of this method to enhance analytical practices in environmental monitoring and public health. Furthermore, the use of sustainable materials and processes aligns with global efforts to reduce environmental impact in analytical chemistry.

Browsing by Author "Rosero Moreano, Milton"

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