Professor and researcher at the Environmental Analytical Chemistry Group at the University of the Balearic Islands (UIB). Environmental Engineer from the National University of Colombia and PhD in Chemical Science and Technology (Palma de Mallorca, Spain). Research experience within the area of analytical chemistry, environmental monitoring and biotechnology.
EDUCATION
Environmental Engineer | MSc and PhD in Chemical Science and Technology
Portable platform for smartphone-enabled arsenic detection using hydride generation and a silver-based metal-organic framework sensor Luz Maza, M.A. Vargas-Muñoz, Edwin Palacio Sensors and Actuators B Chemical, 2026 A portable sensor device was developed for on-site detection of arsenic (As(III)) using the hydride generation technique. The 3D-printed millifluidic device includes two zones: one for sample preparation and another for detection. The sensor zone consists of a silver-based metal-organic framework (Ag-MOF) immobilized with a polyvinylidene fluoride (PVDF) coating on a 3D-printed lid. The arsenic hydride (AsH 3 ) generated in the sample preparation well reacts with the immobilized Ag-MOF, generating silver nanoparticles (AgNPs) that cause the color change from white to dark brown. Visual detection and colorimetric quantification were performed using a 3D-printed portable photo box with LED light panels, a smartphone for image capture, and ImageJ software for RGB analysis. The system required only 1 mL of sample and 5 min for the color reaction. Under optimal conditions, the method exhibited good linearity in two concentration ranges: 20–100 µg L −1 (low range) and 100–500 µg L −1 (high range). The detection limit (LOD) was 10 µg L −1 , and the quantification limit (LOQ) was 20 µg L −1 . Precision, expressed as relative standard deviation (RSD), ranged from 12.9 % to 9.5 %, with recoveries between 91 % and 104 % in milk and groundwater samples. Results were validated against ICP-OES and assessed using the AGREE and BAGI metric tools, confirming the method’s sustainability and practicality. • Portable system for on-site As(III) determination using 3D-printed devices. • Low-cost, rapid, user-friendly method with minimal reagent and sample volumes. • Validated against ICP-OES for accurate As(III) detection in water and milk. • Sustainable solution for real-time arsenic monitoring in food and environmental samples.
Vortex-assisted binary solvent dispersive liquid–liquid microextraction for the determination of two 4-alkylphenols and Bisphenol A in drinking water by HPLC-DAD M.A. Vargas-Muñoz, D.L. Montoya-Cárdenas, Lyseth Bonilla, Edwin Palacio Microchemical Journal, 2025 • A green VA-BS-DLLME method was developed for BPA and alkylphenols in water. • Optimized conditions achieved low LODs (0.08–0.21 μg L −1 ) and high enrichment factors. • Spike recoveries (91.8–104.7%) ensure accuracy and compliance with EU regulations. This work proposes a green and simple method for the determination of trace levels of Bisphenol A and two alkylphenols (4- tert -octylphenol (4-tOP) and 4- tert -butylphenol (4-tBP)) in water intended for human consumption. The method consisted of using vortex-assisted binary solvent dispersive liquid–liquid microextraction (VA-BS-DLLME) as a sample preparation technique, prior to analysis by high-performance liquid chromatography with a diode array detector (HPLC-DAD). The proposed method involved the combination of two microextraction techniques. The binary solvent technique significantly improved the extraction efficiency, while the vortex assistance was used to promote the dispersion of the solvent-sample mixture. A comprehensive multivariate experimental design was carried out to determine the optimal microextraction conditions. The optimal conditions were as follows: binary extraction solvent (100 µL 1-octanol and hexane, 20:80), 3 mL of acetone, and 4 min of vortex agitation. Under the optimum conditions, limits of detection (LOD) between 0.08, 0.13, and 0.21 μg L -1 were found for BPA, 4-tBP, and 4-tOP, respectively. The intra- and inter-day precision (expressed as relative standard deviation − RSD) were less than 7.3 % and enrichment factors ranged from 32 to 74. Spike recovery experiments were carried out on tap water, well water, and bottled water samples, obtaining relative recoveries between 91.8 % and 104.7 %. The results of the proposed method demonstrate that a rapid and sensitive analysis of the target analytes in water samples can be performed, facilitating compliance with regulatory requirements (EU Directive 2020/2184) for the safety and health of drinking water.
A sampling platform incorporating 3D-printed paddles-stirrers coated with metal-organic framework MIL-100(Fe) for in-situ extraction of phenolic pollutants in biodigester supernatant and wastewater effluent samples M.A. Vargas-Muñoz, Carlos Palomino, Gemma Turnes, Edwin Palacio Journal of Environmental Chemical Engineering, 2023 In this work, a portable paddle stirrer platform for solid-phase extraction of chlorophenols, p-nitrophenol, and bisphenol A is presented. These compounds are important environmental pollutants and toxic inhibitors of the anaerobic treatment of wastewater. The platform integrates 3D-printed paddle stirrers coated with the metal-organic framework MIL-100(Fe), which is prepared in 10 minutes using a green microwave-assisted synthesis. This coated stirrer serves as an adsorbent for the preconcentration of phenols. The device is assembled with an electric motor that agitates the sample in a sample container. The sampler can be used for in-situ extraction of the analytes, eliminating the need for transporting samples to the laboratory. The analytes are eluted through ultrasonic desorption before analysis by HPLC-DAD. An exhaustive study of the stirring and extraction parameters was conducted. Under optimum conditions, the detection limits ranged from 0.3 to 1.7 μg L-1, and the precision, expressed as the relative standard deviation, showed intraday and interday ranges of 1.2% to 5.1% and 4.5% to 6.8%, respectively. The accuracy was evaluated using spiked samples of wastewater effluent and biodigester supernatant, and it provided relative recoveries in the range of 91.5% to 108.5%.
Paper sensor-based method using a portable 3D-printed platform and smartphone-assisted colorimetric detection for ammonia and sulfide monitoring in anaerobic digesters and wastewater M.A. Vargas-Muñoz, Julián Morales, Víctor Cerdà, Laura Ferrer, Edwin Palacio Microchemical Journal, 2023 A simple and low-cost field-deployable method using paper sensors in combination with a 3D-printed portable platform to simultaneous determination of ammonia and sulfide has been developed. Ammonia and sulfide are harmful pollutants for the environment and important toxicants inhibiting anaerobic digestion, therefore, are key monitoring parameters during wastewater treatment. The sample preparation system consisted of a well microplate and sensor paper discs placed inside the microplate sealing system. Gas pervaporation and diffusion of ammonia and hydrogen sulfide across a Teflon membrane onto a paper discs, impregnated with bromothymol blue and methylene blue assay reagents, allowed the ammonia and sulfide determination, respectively. The detection system consisted in a 3D-printed photographic lightbox with LED plates and a smartphone. A code was developed in ImageJ for a fast colorimetric measurement of the digital images. Under optimal conditions, limits of detection of 1.3 and 1.7 mg L-1 and linear concentration ranges between 5 and 50 mg L-1 and 5–45 mg L-1, were obtained for ammonia and sulfide, respectively. The analysis of an anaerobic digester and wastewater samples revealed good precisions (RSDs < 10 %) and recoveries (91–105 %). This methodology shows advantages such as a high precision, a simple paper discs preparation and a reusable system.
Automated method for volatile fatty acids determination in anaerobic processes using in-syringe magnetic stirring assisted dispersive liquid-liquid microextraction and gas chromatography with flame ionization detector M.A. Vargas-Muñoz, Víctor Cerdà, L.S. Cadavid-Rodríguez, Edwin Palacio Journal of Chromatography A, 2021 Volatile fatty acids (VFAs) are key parameters to monitor anaerobic digestion processes. Thus, a fast, simple and precise determination of these analytes is necessary for a timely characterization of the biological processes present in municipal solid waste and wastewater treatment plants. In this work, an automated method for the extraction and preconcentration of VFAs, based on dispersive liquid-liquid microextraction with magnetic stirring in syringe, and gas chromatography with flame ionization detector for the separation and detection, is described. The effect of parameters such as the type and volume of extraction solvent, pH, salting out effect and stirring time, was studied using a multivariate and univariate experimental design. Extraction and preconcentration were performed simultaneously using tert-butyl methyl ether (TBME) as the extraction solvent, after stirring 100 s at a constant rate. The detection limits were in the range of 0.1 - 1.3 mg L−1 and a good linearity was observed up to 1000 mg L−1 of the studied VFAs, with a range of R2 between 0.9997 and 0.9999. The intra and interday precision expressed as relative standard deviation (n= 5) varied between 0.7 and 2.4% and between 1.7 and 7.0%, respectively. Subsequently, the developed method was successfully applied to evaluate the presence of VFAs in wastewater samples from anaerobic treatments and an average relative recovery of 102% was obtained.
*PhD Scholarship: Training University Teacher Aid - FPU, 2019. Grants for pre-doctoral contracts to carry out doctoral theses, in Spanish Universities.
*Santander Scholarship - Beca Santander (Iberoamérica 2018). Aid to study a university master's degree at the UIB.
Industry, Institute, or Organisation Collaboration
*Universitat de les Illes Balears (Mallorca, España).
*Universidad Nacional de Colombia (Palmira, Colombia).
INDUSTRY EXPERIENCE
*Scientific researcher - Monitoring of air quality/immissions for the control of the facilities managed by TIRME within the scope of the PDSGRUM (2018-2022).
*Scientific researcher - Radiological Surveillance Program (Radioactivity Environmental Monitoring - REM) of the Nuclear Safety Council (NSC).
