cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14279071.v1
title: EXTRACTION OF PARACETAMOL AND MASS DISPERSION ANALYZES OF TABLETS: COMPARING GENERIC AND BRAND NAME DRUGS IN UNDERGRADUATE EXPERIMENT

description: Medicines are employed in undergraduate courses as motivational strategy. The experiment herein developed compares the extraction of paracetamol from generic and brand name drugs. Tablets were used from two commercial sources purchased from local drugstores. Twenty tablets of each drug type were individually weighed to average weight analysis and mass dispersion was statistically analyzed in simulating of quality control. Average weight had variation in accordance with the limit of ±5% specified by Brazilian Pharmacopeia. Tablets of each drug were pulverized and extracted in triplicate with ethyl acetate, and the active ingredient was obtained and identified by melting point and FTIR analyzes. Comparing different student groups at different times, there was change in the mass of paracetamol extracted by a simple extraction, affording mass recovery in the range of 59±17% to 28±1%. However, mass recovery of paracetamol extraction of generic and brand name drugs was similar in each student group. Under Soxhlet extraction condition mass recovery was 80-85%. The procedure developed was adequate to undergraduate laboratory, involves simple infrastructure and execution, tablets are easily obtained, and allows discussion on pharmaceutical equivalence and interchangeability.
DOI: 10.6084/m9.figshare.14279072.v1
title: PREPARATION AND VALIDATION OF INPUT FILES FOR USE IN THE AIR QUALITY SIMULATOR (CMAQ)

description: According to the inventories carried out by the air pollution control agencies, vehicle emissions are responsible for more than 70% of air pollutants in metropolitan regions. Proper handling of CMAQ input data is an important step in the formation of a database for the model. Thus, it is necessary to insert the meteorological data using the Weather Research and Forecasting (WRF) version 3.9 in the period of the 31 days of January 2013. Four domains with resolutions of 27, 9, 3 and 1 kilometers were used and 21 vertical layers. Spatial Allocator (SA) was used to format the maps and extract the data necessary for the construction of the SMOKE emissions inventory files. WRF was validated comparing the simulation results with data from two weather stations (Jardim Primavera and Nova Iguaçu), using the statistical methods MB, MAGE, RMSE and IOA. SMOKE presented a constant time profile, this occurred because the established hourly function only contemplated daily results without taking into account the variations over the week.
DOI: 10.6084/m9.figshare.14279075
title: MANUAL METHOD FOR THE DEPOSITION OF PHOTOLUMINESCENT INKS BASED ON MIXED LOFs APPLIED TO DOCUMENT ENCONDING

description: In this work, the process of synthesis of Metal-Organic Frameworks containing lanthanide ions (LOFs), accelerated via a precipitating agent, capable of accelerating the process of nucleation of MOF crystals, in order to explore the optical properties of this precursor solution (SP_Gd/EU-MOF), as a quick-response photoluminescent material in the coding of official documents. The SP_Gd/Eu-MOF was deposited on the paper substrates manually, using pilot board master liquid ink pens with medium tip. The SP_Gd/Eu-MOF, was characterized by photoluminescence spectroscopy after crystallization on a vial and at surface of the papers, and the spectra showed identical spectral profiles, showing that the interaction with the substrate surface did not promote significant changes in the site symmetry of Eu3+ ions. After being deposited, the material was excited by UV radiation (λ = 254 nm), and emitted the red color characteristic of the Eu3+ ion. The SP_Gd/Eu-MOF, showed good mechanical stability in the abrasiveness test carried out with a rubber remaining deposited on the substrate, demonstrating it is potential to act as proof of authenticity in the encoding of documents, revealing itself as another low cost alternative for the deposition of photoluminescent inks.
DOI: 10.6084/m9.figshare.14279075.v1
title: MANUAL METHOD FOR THE DEPOSITION OF PHOTOLUMINESCENT INKS BASED ON MIXED LOFs APPLIED TO DOCUMENT ENCONDING

description: In this work, the process of synthesis of Metal-Organic Frameworks containing lanthanide ions (LOFs), accelerated via a precipitating agent, capable of accelerating the process of nucleation of MOF crystals, in order to explore the optical properties of this precursor solution (SP_Gd/EU-MOF), as a quick-response photoluminescent material in the coding of official documents. The SP_Gd/Eu-MOF was deposited on the paper substrates manually, using pilot board master liquid ink pens with medium tip. The SP_Gd/Eu-MOF, was characterized by photoluminescence spectroscopy after crystallization on a vial and at surface of the papers, and the spectra showed identical spectral profiles, showing that the interaction with the substrate surface did not promote significant changes in the site symmetry of Eu3+ ions. After being deposited, the material was excited by UV radiation (λ = 254 nm), and emitted the red color characteristic of the Eu3+ ion. The SP_Gd/Eu-MOF, showed good mechanical stability in the abrasiveness test carried out with a rubber remaining deposited on the substrate, demonstrating it is potential to act as proof of authenticity in the encoding of documents, revealing itself as another low cost alternative for the deposition of photoluminescent inks.
DOI: 10.6084/m9.figshare.14279077.v1
title: INFLUENCE OF IONIC STRENGTH IN DETERMINATION OF pKA BY VOLTAMMETRY

description: The voltammetry is an important analytical technique and also useful for pKa determination. It is a usual procedure of this technique to employ inert electrolyte concentration 100 times higher than redox compound concentration further a pH buffer. However, the ionic strength changes with the solution pH. In this work, we study the consequences of this procedure by using a model system, aniline. A differential pulse voltammetry was used with a glass carbon electrode in 4.0 x 10-3 mol L-1 aniline, 0.04 mol L-1 Britton-Robinson Buffer, NaNO3 as inert electrolyte and pH from 2.0 up to 7.0. The first oxidation peak (0.67V ca.) was used. The pKa determination was performed by using intersection lines at Epeak versus pH. This method was also theoretically discussed for both the oxidant or reducing compound with Brönsted acid-base behavior. For the cited procedure, the ionic strength changed from 0.418 to 0.528 mol L-1, and the experimental pKa (5.691) was far from theoretical one (4.722), still a good fit of lines to experimental data. Using the correct procedure, the experimental pKa (4.938) was near the theoretical one. Therefore, we have proved the need for a more careful adjust of ionic strength in this application.
DOI: 10.6084/m9.figshare.14279077
title: INFLUENCE OF IONIC STRENGTH IN DETERMINATION OF pKA BY VOLTAMMETRY

description: The voltammetry is an important analytical technique and also useful for pKa determination. It is a usual procedure of this technique to employ inert electrolyte concentration 100 times higher than redox compound concentration further a pH buffer. However, the ionic strength changes with the solution pH. In this work, we study the consequences of this procedure by using a model system, aniline. A differential pulse voltammetry was used with a glass carbon electrode in 4.0 x 10-3 mol L-1 aniline, 0.04 mol L-1 Britton-Robinson Buffer, NaNO3 as inert electrolyte and pH from 2.0 up to 7.0. The first oxidation peak (0.67V ca.) was used. The pKa determination was performed by using intersection lines at Epeak versus pH. This method was also theoretically discussed for both the oxidant or reducing compound with Brönsted acid-base behavior. For the cited procedure, the ionic strength changed from 0.418 to 0.528 mol L-1, and the experimental pKa (5.691) was far from theoretical one (4.722), still a good fit of lines to experimental data. Using the correct procedure, the experimental pKa (4.938) was near the theoretical one. Therefore, we have proved the need for a more careful adjust of ionic strength in this application.
DOI: 10.6084/m9.figshare.14279079
title: EXPERIMENTAL ALCHEMY

description: Much is said and written regarding alchemy all across the world, in what could be called a renaissance of alchemical studies. However, relatively little is done in terms of actual alchemical laboratory work. The aim of the project described herein was to show how crucial the development of technical alchemical practice was along the centuries, in the discovery of an immense number of substances, processes and operations, which were of paramount importance in the establishment of modern chemistry. Alchemy is often derided in many circles. On the contrary, for two thousand years it constituted the basis of humankind’s understanding of the material world and the changes undergone by compounds and materials. Here we present an experimental reconstitution of several alchemical discoveries of great importance, using old descriptions followed by modern characterizations. The results were often startling and demonstrated how ancient wisdom bore fruit in different ways, even in the absence of our present-day means of analysis.
DOI: 10.6084/m9.figshare.14279081.v1
title: NIR SPECTROSCOPY AND CHEMOMETRICS IN THE ORGANIC ORIGANUM VULGARE L

description: In recent years, the consumption of organic foods has considerably increased. The basic difference between organic and non-organic food products is the way in which they are produced and processed, and the authenticity of these products is a current trend in food science and analytical chemistry. In this sense, the objective of this work was to propose an analytical methodology based on near-infrared spectroscopy (NIR) coupled with partial least squares with discriminant analysis (PLS-DA) for authentication of organic Origanum vulgare L., a spice known for its characteristic aroma and among the most popular condiments in the world, receiving prominence for its antimicrobial, antioxidant and anti-inflammatory properties. As a result, NIR/PLS-DA was able to promote a rapid and non-destructive analysis in the authentication of organic samples. Important spectral regions for this authentication were highlighted by VIP scores being from 1350 to 1430 nm, and from 1450 to 1480 nm where it is observed absorption due to ROH, ArOH, CONH2, RNH2, CONHR, CH, CH2, and CH3.
DOI: 10.6084/m9.figshare.14279081
title: NIR SPECTROSCOPY AND CHEMOMETRICS IN THE ORGANIC ORIGANUM VULGARE L

description: In recent years, the consumption of organic foods has considerably increased. The basic difference between organic and non-organic food products is the way in which they are produced and processed, and the authenticity of these products is a current trend in food science and analytical chemistry. In this sense, the objective of this work was to propose an analytical methodology based on near-infrared spectroscopy (NIR) coupled with partial least squares with discriminant analysis (PLS-DA) for authentication of organic Origanum vulgare L., a spice known for its characteristic aroma and among the most popular condiments in the world, receiving prominence for its antimicrobial, antioxidant and anti-inflammatory properties. As a result, NIR/PLS-DA was able to promote a rapid and non-destructive analysis in the authentication of organic samples. Important spectral regions for this authentication were highlighted by VIP scores being from 1350 to 1430 nm, and from 1450 to 1480 nm where it is observed absorption due to ROH, ArOH, CONH2, RNH2, CONHR, CH, CH2, and CH3.
DOI: 10.6084/m9.figshare.14279086
title: PLASMONIC NANOMATERIALS: PART II. SURFACE COORDINATION CHEMISTRY AND ITS APPLICATION TO SENSORS AND CATALYSTS

description: In this second part we will discuss how surface chemistry properties of plasmonic nanomaterials can be tailored by applying coordination chemistry, supramolecular and materials chemistry approaches, in which nanoparticles with well-controlled features conjugated with properly chosen molecules are the basis of functional organized structures that can be applied as high sensitivity sensors and high efficient photocatalysts. To achieve this level of control the interactions between the nanomaterials surface and the chemical environment surrounding it, the metal-ligand interactions on the materials surface and the electrons and energy transfers at the interface should be well understood. Therefore, we will show how the Surface Enhanced Raman Effect (SERS) can be explored to study the nanomaterials interface. Finally, we will discuss the role of plasmonic nanomaterials in sensors, more specifically SERS sensors, and photocatalysis.
DOI: 10.6084/m9.figshare.14279086.v1
title: PLASMONIC NANOMATERIALS: PART II. SURFACE COORDINATION CHEMISTRY AND ITS APPLICATION TO SENSORS AND CATALYSTS

description: In this second part we will discuss how surface chemistry properties of plasmonic nanomaterials can be tailored by applying coordination chemistry, supramolecular and materials chemistry approaches, in which nanoparticles with well-controlled features conjugated with properly chosen molecules are the basis of functional organized structures that can be applied as high sensitivity sensors and high efficient photocatalysts. To achieve this level of control the interactions between the nanomaterials surface and the chemical environment surrounding it, the metal-ligand interactions on the materials surface and the electrons and energy transfers at the interface should be well understood. Therefore, we will show how the Surface Enhanced Raman Effect (SERS) can be explored to study the nanomaterials interface. Finally, we will discuss the role of plasmonic nanomaterials in sensors, more specifically SERS sensors, and photocatalysis.
DOI: 10.6084/m9.figshare.14279089.v1
title: CHARACTERIZATION OF AQUATIC ORGANIC MATTER IN A NATURAL ENVIRONMENT IN NORTHEASTERN BRAZIL

description: The organic matter (OM) contained in a natural aquatic environment, located in a tropical region in Notheastern Brazil, was characterized using synchronous fluorescence spectroscopy and UV-Vis absorbance. The synchronous fluorescence spectra did not show qualitative differences for samples collected during dry and rainy seasons. They also revealed two peaks, one at 390 nm and other at 460 nm, associated with humic substances. The lack of peaks with significant fluorescence intensity at 270 - 300 nm and at 320 - 370 nm confirms it is an environment with natural OM. The A254/A436 ratios obtained during the dry and rainy seasons (13.55 to 14.97) indicate the presence of allochthonous OM of terrestrial origin, with high level of aromatic carbon associated with humic substances. The OM photodegradation by natural sunlight was more pronounced in the first five days, with a decrease of FImax from 23.6 to 55.4%. Also, titration with Cu(II) ions was used to determine the complexation ability of the two fluorescent sites, obtaining log K values of 4.26 and 4.27.
DOI: 10.6084/m9.figshare.14279090
title: AN APPROACH BASED ON ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY TO STUDY THE GLYCEROL/BIODIESEL GRAVITY SEPARATION

description: In this study, electrochemical impedance spectroscopy (EIS) is evaluated as a novel application in the biodiesel purification process. EIS is proposed as a tool to study the behavior of charge carriers produced from side reactions or dissociations of some impurities during the gravitational separation of glycerol dispersed in crude biodiesel after the transesterification process. In the present study, EIS combined with a simple capacitor of two parallel plates made of stainless steel ASTM 304 with an area of 7.0 cm2 and a gap between the plates of 0.8 mm is demonstrated to be a promising technique to monitor the biodiesel/glycerol separation as a function of time. From the analysis of the impedance data, collected during the separation process, it was found that the biodiesel resistance increases up to a maximum value and then decreases to a value which corresponds to the final equilibrium state. Considering that the maximum resistance represents the less contaminated biodiesel as a criterion, the proper average biodiesel/separation time of 4 h 14 min ± 1 h 11 min was determined. Another finding from the EIS results suggests that a growing absorbed film exists on the plate surface of the capacitor used as an impedance sensor.
DOI: 10.6084/m9.figshare.14279090.v1
title: AN APPROACH BASED ON ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY TO STUDY THE GLYCEROL/BIODIESEL GRAVITY SEPARATION

description: In this study, electrochemical impedance spectroscopy (EIS) is evaluated as a novel application in the biodiesel purification process. EIS is proposed as a tool to study the behavior of charge carriers produced from side reactions or dissociations of some impurities during the gravitational separation of glycerol dispersed in crude biodiesel after the transesterification process. In the present study, EIS combined with a simple capacitor of two parallel plates made of stainless steel ASTM 304 with an area of 7.0 cm2 and a gap between the plates of 0.8 mm is demonstrated to be a promising technique to monitor the biodiesel/glycerol separation as a function of time. From the analysis of the impedance data, collected during the separation process, it was found that the biodiesel resistance increases up to a maximum value and then decreases to a value which corresponds to the final equilibrium state. Considering that the maximum resistance represents the less contaminated biodiesel as a criterion, the proper average biodiesel/separation time of 4 h 14 min ± 1 h 11 min was determined. Another finding from the EIS results suggests that a growing absorbed film exists on the plate surface of the capacitor used as an impedance sensor.
DOI: 10.6084/m9.figshare.14279092
title: EXTRACTION AND IDENTIFICATION OF FORMULATIONS OF ANABOLIC ANDROGENIC STEROIDS: A FORENSIC EDUCATIONAL APPROACH

description: The use of anabolic androgenic steroids is largely restricted worldwide since they are associated with innumerous side effects and health damage. However, apprehensions of formulations of anabolic agents have been extensively increasing throughout the world, making their analysis a common task in the forensic field. In this sense, a set of three experiments was developed and applied to undergraduate students of Forensic Chemistry dealing with visual inspection of apprehended formulations of anabolic androgenic steroids as well as chemical identification by Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry. Moreover, the classroom evaluated the extraction of steroidal active ingredients by ultrasonic and microwave-assisted extraction. The experimental procedures allied with the theory behind these topics provided an important background to the students on distinct extraction methods and analytical techniques used in the analysis of anabolic agents. Finally, the classroom was led to critically evaluate and interpret the results as well as to question the adequacy of experimental methods used in forensic analysis to stimulate their critical thinking.
DOI: 10.6084/m9.figshare.14279089
title: CHARACTERIZATION OF AQUATIC ORGANIC MATTER IN A NATURAL ENVIRONMENT IN NORTHEASTERN BRAZIL

description: The organic matter (OM) contained in a natural aquatic environment, located in a tropical region in Notheastern Brazil, was characterized using synchronous fluorescence spectroscopy and UV-Vis absorbance. The synchronous fluorescence spectra did not show qualitative differences for samples collected during dry and rainy seasons. They also revealed two peaks, one at 390 nm and other at 460 nm, associated with humic substances. The lack of peaks with significant fluorescence intensity at 270 - 300 nm and at 320 - 370 nm confirms it is an environment with natural OM. The A254/A436 ratios obtained during the dry and rainy seasons (13.55 to 14.97) indicate the presence of allochthonous OM of terrestrial origin, with high level of aromatic carbon associated with humic substances. The OM photodegradation by natural sunlight was more pronounced in the first five days, with a decrease of FImax from 23.6 to 55.4%. Also, titration with Cu(II) ions was used to determine the complexation ability of the two fluorescent sites, obtaining log K values of 4.26 and 4.27.
DOI: 10.6084/m9.figshare.14279092.v1
title: EXTRACTION AND IDENTIFICATION OF FORMULATIONS OF ANABOLIC ANDROGENIC STEROIDS: A FORENSIC EDUCATIONAL APPROACH

description: The use of anabolic androgenic steroids is largely restricted worldwide since they are associated with innumerous side effects and health damage. However, apprehensions of formulations of anabolic agents have been extensively increasing throughout the world, making their analysis a common task in the forensic field. In this sense, a set of three experiments was developed and applied to undergraduate students of Forensic Chemistry dealing with visual inspection of apprehended formulations of anabolic androgenic steroids as well as chemical identification by Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry. Moreover, the classroom evaluated the extraction of steroidal active ingredients by ultrasonic and microwave-assisted extraction. The experimental procedures allied with the theory behind these topics provided an important background to the students on distinct extraction methods and analytical techniques used in the analysis of anabolic agents. Finally, the classroom was led to critically evaluate and interpret the results as well as to question the adequacy of experimental methods used in forensic analysis to stimulate their critical thinking.
DOI: 10.6084/m9.figshare.14279094
title: MOLECULARLY IMPRINTED POLYMER FOR THIACLOPRID: A THEORETICAL INVESTIGATION

description: Thiacloprid (TCP) is a synthetic insecticide, belonging to the class of neonicotinoids (NNCs), which present potential damages to the environment, biodiversity and human health, being necessary its constant monitoring. In this sense, molecularly imprinted polymers (MIPs) have been shown as an excellent alternative for the separation science, since they can recognize molecularly and selectively the analyte in various types of complex sample, such as food, soil, etc., thus contributing to its efficient extraction. In the present work, we have investigated, through DFT calculations, the mechanism of formation of a MIP for the TCP. As main result we obtained the following theoretical protocol for the MIP synthesis: 2-(trifluoromethyl) aryl acid (TFMAA) as FM (functional monomers), in 1:3 stoichiometry, and toluene as the solvent. This theoretical protocol showed the most favorable stabilization energies for the pre-polymerization complexes formed. In addition, it has been shown that the establishment of hydrogen bonds between the TCP and FM play a fundamental role in the stability of the complexes formed. We consider this work quite relevant since it can be used by experimentalists in order to reach an efficient MIP synthesis for TCP.