ABSTRACT Manufacturing pharmaceutical products is one of the most regulated industrial processes due to the importance of its effects on human health. These processes require many physical and chemical determinations through chromatographic techniques coupled with different detectors. However, the pharmaceutical industry is not considering the growth that spectroscopic techniques have had in these fields of application, especially to monitor the blending process. This study evaluates different sampling methods for pharmaceutical blending processes by near-infrared spectroscopy (NIRS) and Vis-NIR spectroscopy. The pharmaceutical mixture consisted of three active ingredients at different concentrations. Various qualitative and quantitative strategies were used to evaluate the endpoint of the blending process. The results revealed the feasibility of different spectral analyses to establish the homogeneity of the mixture, which may be especially useful for applications at the industrial level in routine analysis or as a first choice. HPLC confirmed the final blend.

ABSTRACT Food packaging for traditional foods mainly serves to isolate foods from external environmental. For this reason, it is a growing interest in developing active packaging materials that can extend foodstuff shelf-life. Also, it could counteract the level of contamination by plastic in the environment using biodegradable polymers. For this purpose, poly(3-hydroxybutyrate) (PHB)-thermoplastic starch (TPS)/ organically modified montmorillonite (OMMT)/eugenol bionanocomposites were prepared by melt blending. Morphology, thermal, and mechanical properties were determined by comparing the concentration influence of eugenol and clay on the PHB-TPS blend and PHB. X-ray diffraction measurements revealed the existence of exfoliated morphology in the bionanocomposites. Atomic force microscopy imaging (AFM) showed the difference in morphological characteristics of the pure PHB and the prepared bionanocomposites. Roughness analysis from the AFM data indicates that the presence of clay and TPS increases the roughness with respect to PHB. Dynamic mechanical thermal analysis (DMTA) showed that bionanocomposites have an improved storage module. Finally, properties such as hardness and elastic modulus studied by nanoindentation showed a decrease with respect to PHB. The presence of eugenol in the bionanocomposites does not show a significant effect on the different properties.

ABSTRACT The study and determination of the antioxidant capacity of the Greigia Sphacelata fruit were carried out. G. sphacelata is an endemic fruit of central-southern Chile, better known as Chupón or Quiscal. Spectrophotometric and modified ORAC test were developed for antioxidant capacity determinations, and later an electrochemical method was developed by differential impulse voltammetry (DPV) with a vitreous carbon electrode for the quantification of the antioxidant capacity expressed in equivalent of the Trolox standard in µmolL-1. Once the voltammetric test was developed, the correlation study between both methods used to determine the antioxidant capacity of Greigia sphacelata was carried out. The results of the determination of the antioxidant capacity of Greigia sphacelata by ORAC test report an antioxidant capacity of 3525 µmol/100gequivalents of Trolox. Concerning the concentration obtained by the electrochemical methodology, 724 µmol/100g Trolox equivalents is obtained for a linear correlation r = 0.969 with the spectrophotometric method.

ABSTRACT The removal of organic contaminants, especially trimethylamine (TMA), have been successfully achieved using carbon activate. In this article, we report the formation of carbon activate (CA-SM) isolated from sub-bituminous coal in small mantles (SM) at the Mine “Mantos Negros” (Lebu, Chile). This coal was subjected to thermal oxidation with CO2 at 950 °C and their TMA adsorption capacity evaluated. SM and CA-SM were physically and chemically characterized showing that the activated carbon increased the surface porosity as well as the Iodine Index from 2.5 mg I2/g to 434 mg I2/g coal. The proximal and elementary analyses of CASM showed a significant reduction of sulfur, nitrogen and hydrogen, and increased composition of carbon and oxygen. These results together with FTIR and Boehm titration suggest that the surface composition of the activated carbon is acidic in nature. The adsorption of TMA by CA-SM was evaluated in dissolution at different pH and exposure time conditions. We found that TMA can be fully absorbed (50 ml TMA at 4 mg/L and 0.2000g of CA-SM) under neutral and basic pH after 60 minutes of exposure. The feasibility of producing activated carbon from sub-bituminous coal from Province of Arauco, Chile, is a promising alternative to develop coal-based products displaying adsorbent properties useful to control amine-derived contaminants produced in the fishing industry.

ABSTRACT Capsaicinoids are organic compounds present in several foods like chili peppers. This group of molecules are responsible of fruit pungency, as well as, of several healthy properties. The present work reports an optimized and validated liquid chromatography method coupled to fluorescence and mass spectrometry detectors for a selective determination of capsaicin in Chili peppers (Capsicum annum and C. pendulum). To the best our knowledge this is the first report about capsaicin determination in chili peppers commercialized in Chile. Chromatographic conditions were optimized giving the following optimal conditions: 76% organic phase (MeOH: ACN: acetic acid (50:50:0.1 v/v/v) at 9 min of gradient program and column temperature of 35°C. With these conditions capsaicin, dihydrocapsaicin and nordihydrocapsaicin were separated in 15 min. Data calibration curve (0.01-2.00 mg L-1) fitted a linear regression model with a determination coefficient (R2) of 0.9986. Repeatability (relative standard deviation, RSD) and intermediate precision (RSD) showed values of 1.51% (n=6) and 1.04% (n=3), respectively. Recovery (n=3) at three levels ranged from 94.80 to 109.40%, (RDS <2.39%). The method was applied to analyze 10 chili peppers varieties commercialized in Chile. A broad range of capsaicin and dihydrocapsaicin contents were observed, finding values from 0.1 up to 127.3 µg g-1.

ABSTRACT Acetazolamide (ACZ) is a carbonic anhydrase inhibitor that exhibits diuretic activity. In medicine, it is principally used in open-angle glaucoma, for prevention or amelioration of symptoms associated with acute high-altitude sickness and as an adjunct to other anticonvulsants in centrencephalic epilepsies. Furthermore, ACZ is sometimes used by athletes to mask the presence of doping substances, so its use has been banned in competitions. The aim of this work was the development of a sensor to determine ACZ in pharmaceuticals, as quality control way, and serum, for clinical and doping analyzes. The sensor has been developed modifying a glassy carbon electrode with carbon nanofibers. The electrochemical characterization of the sensor was performed by cyclic voltammetry using the redox mediator potassium ferrocyanide. ACZ electrochemical behavior was studied as well. Measurements were performed in a conventional three electrodes cell using differential pulse voltammetry. The influence of some experimental variables involved in the preparation and performance of the sensor –amount of modifier, supporting electrolyte, pH, scan rate and pulse amplitude– were optimized. This methodology provided a linear calibration plot for ACZ in the 1 – 17 µM concentration range. Furthermore, the proposed sensor exhibited suitable analytical properties, with detection and quantification limits of 0.06 µM and 0.2 µM respectively; analytical sensitivity of 1.142 µA/µM, repeatability of 0.72 %, and it was applied to determine ACZ in pharmaceuticals (tablets) and spiked human serum, being an excellent tool to perform quality control and antidoping control.

ABSTRACT The effect of different variables in the electrochemical removal of estriol (E3) in aqueous solution was studied and it was compared with the removal of 17 α- Ethinylestradiol. The photoelectroxidations were carried out with DSA electrode (Ti/RuO2), varying the pH, substrate concentration and supporting electrolyte, potential configuration of saline bridge, reactor volume, and light source. Results for both Estriol and 17 α- Ethinylestradiol are similar, showing to be the best removals at concentrations of 500 ug/L of substrate, volumes to be treated of 90 ml of solution, saline bridge of 30 cm in length, voltages between 0.8 and 3, concentration of Na2SO4 of 0.1 M, pH between 6 and10, and UV lamp of 125 W.

The chemical and sorptive characteristics of mineral coals extracted from a mine in Lebu (Biobío Región, Chile) and its derivatives were studied. These derivatives were obtained by applying a thermal treatment in an environment with N2 and CO2 at different experimental conditions, in order to increase their specific surface. In addition, coals were characterized by using proximal analysis, elementary analysis and petrographic analysis. In order to know their structureand surface, Boehm titration analysis, FTIR infrared spectroscopy, X-ray diffraction and scanning electron microscopy were performed. The surface of the selectedcarbons was modified by selectively oxidizing it with (NH^S^O and with H2O2 e impregnating with an iron solution for the study with H2O2 In the oxidation ofH2O2, the work was carried out at different pH. The results show a moderate homogeneity between different types of seams studied, whereas when coals are treatedwith heat or strong oxidants, increases its surface and can be used with analytical applications (v.g. electroanalytical sensors).

An analytical testing study of interference standard method (IFS) for metals in wines with low and high residual sugar by inductively coupled plasma mass spectrometry (ICP-MS) was evaluated. Selection of IFS probes was based on the ions formed in the argon plasma, such as natural 38Ar+ or contaminant like 83Kr+ or also ions provided from the matrix sample (for instance, 13C+). The analytical signal was obtained from ratio between the original signals of the analyte and those of the IFS probe species. The accuracy was confirmed using a t-test statistic for comparison between the concentrations obtained by Flame Atomic Absorption Spectrometry (FAAS) and ICP-MS. In a first study, the IFS effect was analyzed by comparing the correlation coefficients obtained with or without dividing the analytical signal by the IFS. Using the 83Kr+ IFS probe provide always better results in the determination of Fe, Mn and Zn compared to 13C+ and 38Ar+.

The purpose of this study was to investigate whether the Electrochemical Dissolution (DE) facilitates the retrieval of fractured files, from Endo-Training block with an artificial root canal, by using ultrasonic techniques (US). Twenty Endo-Training block with an artificial single canal with working length 16 mm and twenty nickel-titanium (NiTi) Protaper Universal rotary files were used. 10 Shaping S1 files and 10 Shaping S2 files, were sectioned transversally within the conduit, to 5mm of the apical tip. Twenty samples were divided into four groups: Group1 and 3 received the action of DE and US, and groups 2 and 4 received the action of US. To remove the fragments we used Staging Platform and Dental Microscope. Outcome was analyzed statistically by Student t test. Statistical Analysis showed a significant difference in retrieval time of the fragments and weight loss mass of Endo training block ultrasonic tips were used, between groups that applied Ultrasonic with electrochemical dissolution and the group using only ultrasonic. It can be concluded that there was weight loss mass of separated fragment by electrochemical action, however, it was not sufficient and its use alone was inconclusive to retrieve the fragments. The procedure needs to be complemented with the use of the staging platform, ultrasonic tips and Dental Microscope.

Este estudio tiene como propósito determinar si la Disolución Electroquímica (DE) favorece el retiro de fragmentos de limas fracturadas, insertos en bloc endodónticos de entrenamiento de resina, con un conducto radicular simulado, mediante el uso de ultrasonido (US). Se utilizaron 20 bloc y 20 limas rotatorias usadas ProTaper Universal de NiTi Shaping Files, 10 S1, 10 S2, que fueron fracturadas dentro del conducto, a 5 mm desde la punta apical y divididos en Grupo1 y 3 que recibieron la acción de la DE y US; y Grupo 2 y 4 sólo utilizó US. Para retirar los fragmentos se utilizó Plataforma de Trabajo y Microscopio Dental. Los datos fueron analizados con la prueba T de Student. Los resultados indican que existen diferencias estadísticamente significativas en el tiempo de retiro de los fragmentos y en la pérdida de masa del bloc de entrenamiento por el uso del ultrasonido, en los grupos que se aplicó Disolución Electroquímica más Ultrasonido. Se puede concluir que la acción electroquímica permite que exista pérdida de masa del fragmento fracturado, sin embargo, no es suficiente y su sola utilización no es concluyente para retirar los fragmentos, es necesario complementar el procedimiento con la utilización de la Plataforma de Trabajo, puntas de ultrasonido y el Microscopio Dental.

A detecção eletroquímica de arsenito com eletrodos de fio de prata (SWE) ou de disco de prata (SDE) foi realizada em soluções aquosas inorgânicas, as quais são similares àquelas encontradas em condições naturais. Voltametria cíclica (CV), voltametria de varredura linear (LSV) e voltametria de redissolução anódica (ASV) foram aplicadas. Os fatores investigados foram pH, natureza e concentração do eletrodo de suporte e tempo e voltagem de deposição para ASV. As mudanças de corrente e potencial de pico anódicos de As(III) em soluções padrão (por exemplo, 0,1 mol L-1 Na2SO4, NaNO3, HNO3 and H2SO4) foram avaliadas. Os meios neutro e básico de sais inorgânicos intensificaram a sensibilidade do eletrodo de prata mais que o meio ácido. Então, foi possível trabalhar em meio alcalino com sensibilidade aumentada para As(III) (limite de detecção de 90 ng L-1). A resposta analítica melhorada fez este sistema comparável a um eletrodo de nanoarranjo. Como o intervalo de uso destes eletrodos era largo, SWE (área de 6,47 mm²) foi aplicado para monitorar a água de torneira usando 0,1 mol L-1 Na2SO4 como eletrodo de suporte para detectar quantidades acima de 0,5 mg L-1 As(III).

The electrochemical detection of arsenite with silver wire (SWE) or silver disc (SDE) electrodes was carried out in inorganic aqueous solutions, which are similar to those found under natural conditions. Cyclic voltammetry (CV), linear sweep voltammetry (LSV) and anodic stripping voltammetry (ASV) were applied. The investigated factors were pH, nature and concentration of supporting electrolyte and deposition time and voltage for ASV. The changes in the As(III) anodic peak current and potential in standard solutions (e.g., 0.1 mol L-1 Na2SO4, NaNO3, HNO3 and H2SO4) were evaluated. The neutral and basic media of inorganic salts were found to enhance the silver electrode sensitivity more than the acidic media. Thus, it was possible to work in alkaline medium with increased sensitivity for As(III) (limit of detection of 90 ng L-1). The improved analytical response made this system comparable to a nanoarray electrode. As the range of use of these electrodes was wide, SWE (area of 6.47 mm²) was applied to monitor tap water using 0.1 mol L-1 Na2SO4 as supporting electrolyte to successfully detect quantities above 0.5 mg L-1 As(III).