Calculate content of vitamin C in a pharmaceutical compound. PBL used as a strategy to make easy to learn chemistry at university.

In Project-Based Learning, teacher transmits to the students the contents that the curriculum marks, helping to motivate them and awaken their concerns about the previous knowledge. This way of working intends that students discover and feel that what they are learning in class has an application, in some cases close to their reality, it is not simple content that they must pass to pass the course. It is intended that they are aware that the learning they are doing is helping them to prepare for life. This work focuses on the utility of the laboratory as a space with a problem-solving approach, that is, contextualizing problems and fulfilling a series of purposes. These purposes are the ability to internalize general and specific knowledge (know), acquire technical and procedural skills (know how), develop attitudes (know how to be) and social skills (know how to live together). The laboratories allow the student to be trained, since the students are responsible for their own learning, thus contributing to their self-learning; Teamwork implies assertive communication, both in oral and written communication, which contributes to improving their skills. The students learned to discuss and support their ideas. Therefore, it was revealed that it is a training for the students, and it is managing to improve the performance of the students. The results have shown, after the students completed a questionnaire, after the laboratories, 59% of the students indicated that the experience contributed to their learning (aspects such as comprehension and self-learning) compared to 41% who thought that it did not help in this regard; 88% indicated that it helped them better understand the experience they were carrying out and only 14% stressed that there was no coherence between theory and practice.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Simultaneous determination of traces of PT, PD, OS, IR, RH, AG and AU by using magnetic nanoparticles solid phase extraction coupled with ICP OES

The direct analysis of these target analytes is very limited being essential sample pre-treatment techniques and the use of very sensitive instrumental techniques to carry out determinations. The inductively coupled plasma optical emission spectrometry shows a poor sensitivity because the concentration of some elements in environmental samples is below the detection limit of ICP OES. To solve this problem, preconcentration separation procedures have been proposed, minimizing the spectral and matrix interferences. Thus, enrichment is a very important issue for achievement of low detection limits [1-4]. In this study, a chelating resin 1,5 bis (di 2 pyridil) methylene thiocarbonohydrazide bonded to iron oxide magnetic nanoparticles (DPTH-MNPs) were synthesized. These magnetic nanoparticles were employed as a solid phase extraction (SPE) adsorbent for the separation and concentration of trace amounts of 7 elements (Au, Ag, Pd, Pt, Ir, Rh and Os) from environmental water samples. The main aim of this work was to develop a precise and accurate method for the simultaneous determination of the maximum possible number of elements by using this new absorbent and a multimode sample introduction system (MSIS). The MSIS acts as a system for the generation, separation and introduction of chemical vapours (CVG) and also as an introduction system for sample aerosols, in a simultaneous form, into an inductively coupled plasma-optical emission spectrometer. The on-line SPE-CVG-ICP-OES system developed was applied in the determination of the aforementioned metals in natural water samples (sea water, estuarine, lake and river water), with the least demanding and simple sample preparation procedure. The developed method was validated by analysing natural water certified reference materials (TMDA 54.4 fortified lake waters and SRM 1643e, trace elements in water; and National Institute of Standards and Technology (NIST), NIST-2557 autocatalyst). Sea water, tap water and well water samples collected from Malaga (Spain) were also analysed. The procedure has been demonstrated to be fast, easy, automatic, selective and economical, and the sensitivity was good. The main advantage of DPTH-MNPs is its very good stability and resistance because chemisorption of chelating molecules on the surface of solid supports provides immobility, mechanical stability and insolubility. The precision (RSD), accuracy (by standard addition or recovery) and limit of detection (LOD) were used to evaluate the characteristics of the procedure. Furthermore, the proposed method was applied in the simultaneous determination of the 7 elements mentioned above with a sample throughput of about 13 h-1, thereby, reducing the time of analysis and the volume of reagents and sample required. References [1] M. Tuzen, M. Soylak, D. Citak, H.S. Ferreira, M.G.A. Korn, M.A. Bezerra, A pre-concentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry, Journal of Haz-ardous Materials 162 (2009) 1041–1045. [2] Y. Cui, X. Chang, Y. Zhai, X. Zhu, H. Zheng, N. Lian, ICP-AES determination of trace elements after preconcentrated with p-dimethylaminobenzaldehyde-modified nanometer SiO2 from sample solution, Microchem. J. 83 (2006) 35–41. [3] P. Liang, B. Hu, Z. Jiang, Y. Qin, T. Peng, Nanometer-sized titanium dioxide micro-column on-line preconcentration of La, Y, Yb, Eu, Dy and their determination by inductively coupled plasma atomic emission spectrometry, J. Anal. Atom. Spectrom. 16 (2001) 863–866. [4] B. Feist, B. Mikula, K. Pytlakowska, B. Puzio, F. Buhl, Determination of heavy metals by ICP-OES and F-AAS after preconcentration with 2,2-bipyridyl and erythrosine, J. Hazard. Mater. 152 (2008) 1122–1129.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Sequential determination of traces of As, Sb and hg by on-line magnetic solid phase extraction coupled with Hr-Cs-Cvg-Gfaas

A green and rapid method was developed for the simultaneous separation/preconcentration and sequential monitoring pf arsenic, antimony and mercury by flow injection magnetic solid phase extraction coupled with on-line chemical vapor generation and determination by high resolution continuum source graphite furnace atomic absorption spectrometry. The system is based on chelating/cationic retention of the analytes onto a magnet based reactor designed to contain functionalized magnetic nanoparticles (MNPs). The MNP score allows overcoming the back-pressure problems that usually happen in SPME methods with NPs thanks to the possibility of inmobilizing the MNPs by applying an external magnetic field. Several chemical and flow variables were considered as factors in the optimization process using central composite designs. With the optimized procedure the detection limits obtained were 0.2, 0.003 and 0.4 µg/L for As, Sb and Hg respectively. For the quality control of the analytical performance and the validation of the developed method the analysis of two certified samples TM 24.3 and TMDA 54.4 Fortified Lake Waters was addressed. The results showed good agreement with the certified values.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Rapid Magnetic Dispersive solid phase extraction to preconcentration/determination of Cd and Pb in aqueous samples

A new magnetic dispersive solid phase extraction (MDSPE) method and graphite furnace atomic absorption spectrometry (GFAAS) have been combined for the analysis of Cd and Pb in environmental samples. For the preconcentration, a shell structured Fe3O4@graphene oxide nanospheres was synthetized and characterized. The material was suspended in the ionic liquid 1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4], the obtained stable colloidal suspension is named ferrofluid. GO presents excellent adsorbent properties for organic species due to the presence of the electronic π system. For this reason, the organic ligand [1,5-bis-(2-dipyridyl) methylene] thiocarbonohydrazide (DPTH) was used in order to form organic complexes of Cd and Pb. Once the DPTH ligand has been added to sample, the ferrofluid was injected and finely dispersed in the sample solution in order to extract the formed chelates. The complete adsorption of the chelates took place within few seconds then, the solid was separated from the solution with the aid of a strong magnet. Cd and Pb ions were desorbed from the material with 1 mL of acid nitric 5% solution and quantified by GFAAS. All experimental and instrumental variables were optimized. The analytical performances of the optimized method were: EF (Enrichment factor): 200 with LODs (detection limit): 0.005 and 0.004 µg L-1 and LOQs (determination limit): 0.017 and 0.013 µg L-1, for Cd and Pb, respectively. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be < 5%. The accuracy of the proposed method was verified using certified reference materials (SLRS-5, SPS-SW2, and BCR-723) and by determining the analyte content in spiked aqueous samples. Sea waters and tap water samples collected from Málaga (Spain) were also analysed. The determined values were in good agreement with the certified values and the recoveries for the spiked samples were around 100% in all cases.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Cold vapour generation electrothermal atomic absorption spectrometry and solid phase extraction based on a new nanosorbent for sensitive HG determination in environmental samples (sea water and river water)

Reunión bianual del Grupo Regional Andaluz de la Sociedad Española de Química AnalíticaMercury is not an essential element for plant or animal life and it is a potential environmental toxic because of its tendency to form covalent bonds with organic molecules and the high stability of the Hg-C bond. Reports estimate a total mercury concentration in natural waters ranging from 0.2 to 100 ng L-1. Due to this fact, highly sensitive methods are required for direct determination of such extremely low levels. In this work, a rapid and simple method was developed for separation and preconcentration of mercury by flow injection solid phase extraction coupled with on-line chemical vapour generation electrothermal atomic absorption spectrometry. The system is based on chelating retention of the analyte onto the mini column filled with a mesoporous silica functionalized with 1,5 bis (di-2-pyridyl) methylene thiocarbohydrazide. The main aim of this work was to develop a precise and accurate method for the determination of the Hg. Under the optima conditions and 120 s preconcentration time, the detection limit obtained was 0.009 μg L-1, with RSDs 3.7 % for 0.2 μg L-1, 4.8 % for 1 μg L-1 and enrichment factor 4, Furthermore, the method proposed has permitted the determination of Hg with a reduction in the analysis time, the sample throughput was about 18 h-1, low consumption of reagents and sample volume. The method was applied to the determination of Hg in sea water and river water. For the quality control of the analytical performance and the validation of the newly developed method, the analysis of two certified samples, TMDA 54.4 Fortified Lake, and LGC6187 River sediment was addressed. The results showed good agreement with the certified values.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Determination of Pb using F3eO4 GO join to DPTH for ferrofluid based dispersive solid phase extraction

In this work has been described a green and rapid method the synthesis of Fe3O4@GO nanospheres via chemical covalent bonding method. The Fe3O4@GO DPTH was applied to ferrofluid based dispersive solid phase extraction of lead as a model analyte using an ionic liquid carrier. The ferro fluid allows the rapid extraction of lead ions using a low amount of sorbent material. Besides, the magnetic separation greatly improved the separation rate. The presented method is highly time saving due to the high dispersion of the sorbent in the aqueous phase and also there is no need to shake the sample solution. The other benefits of the proposed methods are simplicity of operation, low cost, high sorption capacity, high recovery and high preconcentration. In order to optimize the method the following parameters were studied: sample solution pH, concentration of DPTH, extraction time, amount of sorbent, desorption conditions, influence of ionic strength, and tolerance of potentially interfering ions. The sample or standard solution containing Pb(II), DPTH (0.05% ethanol w/v), NaCl (0.5 %, w/v) and buffer (pH = 5.6) was poured into high volume. Then 240 µL of ferrofluid was injected rapidly into the sample solution through a syringe. Thereupon, a dark cloudy suspension was formed, ferrofluid was dispersed thoroughly in solution and the complex of Pb-DPTH was extracted in a few seconds. Subsequently, a strong magnet was placed at the bottom of the tube to let the extractant settle. After about 3 min, the solution became clear and the supernatant was discarded simply by decanting it. Afterwards, the magnet was removed and 1 mL of nitric acid (2.0 mol L−1) was introduced to the vial to desorb the Pb by sonication. Finally, the sorbent was separated by positioning the magnet to the outside of the tube and the concentration of Pb in acidic aqueous phase was determined by ETAAS.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

New methodologies to improve the chemistry learning at University

The main objective was to improve the learning of Chemistry subject using Flipped classroom, because it makes class time more engaging. The lecture portion of General Chemistry courses in engineers degrees have been pushed outside the classroom using pre recording technology and steaming delivery of content, to make classes more interactive and participative. The Flipped classroom model has become one of the main topics in the higher education space in recent years thanks to improvements in technology. Those videos where recorded by the students about themes like radioactivity, chemistry bonds, the evolution of the atom theory, and so on. Those videos were showed on classes and after the videos were evaluated using a rubric. Statistical significance of the data has shown, and proved with, that implementing the Flipped classroom model could not only benefit professors, but also it could also help us adapt the classes to the various learning styles that exist among the students.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Green chemistry: advancing planetary phosphorus sustainability through the synergy of graphene oxide modified with magnetic nanoparticles (M@GO) for extracting tertiary effluent phosphorus in sewage treatment plants.

Securing the enduring sustainability of global phosphorus (P) utilization has become a key societal priority. The application of green chemistry and green engineering presents an opportunity to mitigate these challenges and contribute to the sustainable closure of the global phosphorus cycle by addressing the extraction of phosphorus from waste and subsequent reuse. In this manuscript the feasibility of a novel magnetic graphene oxide for wastewater phosphorus recovery/removal is described. The primary technical benefit of this solid adsorbent lies in its easy separation from treated water through magnetic field application. The key factors affecting the sorption efficiency (contact time, pH, and adsorbent dosage) are studied. During the first 30 min, at pH 8 and with a dosage of 0.8 g L−1, 25% of the initial concentration is reduced. Among the 3 thermodynamic models proposed, the Langmuir isotherm provides the best fit to the experimental results, with a maximum adsorption capacity of 2.69 mg g−1. Four kinetic models are evaluated to describe the adsorption of phosphorus on this magnetic graphene oxide for different initial adsorbate concentrations and adsorbent dosages. Among them, Langmuir kinetics provide the best fit to the experimental data. The adsorption rate constant is 0.72 L mg−1 h−1, and the desorption rate is 0.58 h−1, in accordance with the identified Langmuir isotherm. Parameter values calculated from a mass transfer kinetic model indicate that the mass transfer of phosphorus between the bulk liquid and the solid surface is not the rate-limiting step of the adsorption process. Following the separation of this magnetic solid from the treated wastewater, an ammonia aqueous solution can recover the phosphorus from the solid adsorbent. Preliminary results show absorbed phosphorus recovery yields above 99% with a solid–liquid ratio up to 5 times higher than that used in the adsorption process.Spanish Ministry of Science and Innovation [Research Project PID2021-126794OB-I00] University of Málaga [Support for Prototypes E3/05/21], [II Plan Propio (B1-2022_20 and B4-2023-19)] CEI MAR funds. Spanish Ministry of Science and Innovation. Collaboration grant and fellowship FPU18/05371 Funding for open access charge: Universidad de Malaga/CBUA

Influence of Atg5 Mutation in SLE Depends on Functional IL-10 Genotype

Increasing evidence supports the involvement of autophagy in the etiopathology of autoimmune diseases. Despite the identification of autophagy-related protein (Atg)-5 as one of the susceptibility loci in systemic Lupus erythematosus (SLE), the consequences of the carriage of these mutations for patients remain unclear. The present work analyzed the association of Atg5 rs573775 single nucleotide polymorphism (SNP) with SLE susceptibility, IFNα, TNFα and IL-10 serum levels, and clinical features, in 115 patients and 170 healthy individuals. Patients who where carriers of the rs573775 T* minor allele presented lower IFNα levels than those with the wild genotype, whereas the opposite result was detected for IL-10. Thus, since IL-10 production was regulated by rs1800896 polymorphisms, we evaluated the effect of this Atg5 mutation in genetically high and low IL-10 producers. Interestingly, we found that the rs573775 T* allele was a risk factor for SLE in carriers of the high IL-10 producer genotype, but not among genetically low producers. Moreover, IL-10 genotype influences SLE features in patients presenting the Atg5 mutated allele. Specifically, carriage of the rs573775 T* allele led to IL-10 upregulation, reduced IFNα and TNFα production and a low frequency of cytopenia in patients with the high IL-10 producer genotype, whereas patients with the same Atg5 allele that were low IL-10 producers presented reduced amounts of all these cytokines, had a lower prevalence of anti-dsDNA antibodies and the latest onset age. In conclusion, the Atg5 rs573775 T* allele seems to influence SLE susceptibility, cytokine production and disease features depending on other factors such as functional IL-10 genotype

Phosphorus removal and recycled from tertiary effluent in sewage treatment plant using graphene modified with magnetic nanoparticles (M@GO).

Phosphorus is employed in detergents, as fertilizers in agriculture, etc. As a nutrient for plants, too much phosphorus can cause increased growth of algae and large aquatic plants, which can result in decreased levels of dissolved oxygen– a process called eutrophication. On the other hand, P is a relatively limited resource, considered by the European Union as a strategic interest material. Thus, the removal and recycled of P from the sewage treatment plants is of great interest to the society. In this work, a new patented magnetic graphene oxide (M@GO) for the removal of phosphorus from wastewater is studied. The main technical advantage of this solid adsorbent is its easy separation from the treated water by applying a magnetic field. The key factors affecting the sorption and elution efficiency are studied. The thermodynamic adsorption model that provides a best fit was the Langmuir isotherm. The mass transfer kinetic model indicates that the mass transfer of P between the bulk liquid and the solid surface is not the rate-limiting step of the adsorption process. The P adsorption on M@GO was demonstrated by TEM, XPS, FTIR. After the adsorption, an ammonia aqueous solution has provided to be the best eluent to recover the phosphorus from the solid adsorbent, as ammonium phosphate, with recovery yields above 90%. The results of this work have driven to the design of a new magnetic reactor for the treatment of waste water. Acknowledgements The authors thank to Spanish Ministerio de Ciencia e Innovación, Project PID2021-126794OB and the II Plan Propio UMA.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech