Determination of tributyltin at parts-per-trillion levels in natural waters by second-order multivariate calibration and fluorescence spectroscopy

This work presents a non-sophisticated approach for the trace determination of tributyltin, the most toxic organotin species, in very interfering environments, combining fluorescence measurements of its morin complex and the selectivity of second-order chemometric algorithms. The power of MCR–ALS (multivariate curve resolution/alternating least-squares) to quantify tributyltin through fluorescence excitation–emission matrices in the presence of its main degradation products and of a pool of additional twenty-three metal ions is demonstrated. The applied algorithm successfully faces the challenge of solving the strong overlapping among the spectra of the several sample components. The proposed methodology was applied to tap, river, lagoon and seawater spiked samples, obtaining satisfactory results at ngL −1 levels, after a pre-concentration step on a C18 membrane, demonstrating the analytical potential of the proposed methodology.Fil: Bravo, Manuel. Pontificia Universidad Católica de Valparaíso. Instituto de Química. Laboratorio de Química Analítica y Ambiental; Chile.Fil: Aguilar, Luis Felipe. Pontificia Universidad Católica de Valparaíso. Instituto de Química. Laboratorio de Fotofísica y Espectroscopia Molecular; Chile.Fil: Quiroz, Waldo. Pontificia Universidad Católica de Valparaíso. Instituto de Química. Laboratorio de Química Analítica y Ambiental; Chile.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Escandar, Graciela Mónica. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario (IQUIR-CONICET); Argentina

Scope of partial least-squares regression applied to the enantiomeric composition determination of ketoprofen from strongly overlapped chromatographic profiles

Valuable quantitative information could be obtained from strongly overlapped chromatographic profiles of two enantiomers by using proper chemometric methods. Complete separation profiles where the peaks are fully resolved are difficult to achieve in chiral separation methods, and this becomes a particularly severe problem in case that the analyst need to measure the chiral purity, i.e., when one of the enantiomers is present in the sample in very low concentrations. In this report, we explore the scope of a multivariate chemometric technique based on unfolded partial least-squares regression, as a mathematical tool to solve this quite frequent difficulty. This technique was applied to obtain quantitative results from partially overlapped chromatographic profiles of R- and S-ketoprofen, with different values of enantioresolution factors (from 0.81 down to less than 0.2 resolution units), and also at several different S:R enantiomeric ratios. Enantiomeric purity below 1% was determined with excellent precision even from almost completely overlapped signals. All these assays were tested on the most demanding condition, i.e., when the minor peak elutes immediately after the main peak. The results were validated using univariate calibration of completely resolved profiles and the method applied to the determination of enantiomeric purity of commercial pharmaceuticals.Laboratorio de Investigación y Desarrollo de Métodos Analíticos (LIDMA

Vitruvius+: An area-efficient RISC-V decoupled vector coprocessor for high performance computing applications

The maturity level of RISC-V and the availability of domain-specific instruction set extensions, like vector processing, make RISC-V a good candidate for supporting the integration of specialized hardware in processor cores for the High Performance Computing (HPC) application domain. In this article,1 we present Vitruvius+, the vector processing acceleration engine that represents the core of vector instruction execution in the HPC challenge that comes within the EuroHPC initiative. It implements the RISC-V vector extension (RVV) 0.7.1 and can be easily connected to a scalar core using the Open Vector Interface standard. Vitruvius+ natively supports long vectors: 256 double precision floating-point elements in a single vector register. It is composed of a set of identical vector pipelines (lanes), each containing a slice of the Vector Register File and functional units (one integer, one floating point). The vector instruction execution scheme is hybrid in-order/out-of-order and is supported by register renaming and arithmetic/memory instruction decoupling. On a stand-alone synthesis, Vitruvius+ reaches a maximum frequency of 1.4 GHz in typical conditions (TT/0.80V/25°C) using GlobalFoundries 22FDX FD-SOI. The silicon implementation has a total area of 1.3 mm2 and maximum estimated power of ~920 mW for one instance of Vitruvius+ equipped with eight vector lanes.This research has received funding from the European High Performance Computing Joint Undertaking (JU) under Framework Partnership Agreement No 800928 (European Processor Initiative) and Specific Grant Agreement No 101036168 (EPI SGA2). The JU receives support from the European Union’s Horizon 2020 research and innovation programme and from Croatia, France, Germany, Greece, Italy, Netherlands, Portugal, Spain, Sweden, and Switzerland. The EPI-SGA2 project, PCI2022-132935 is also co-funded by MCIN/AEI/10.13039/501100011033 and by the UE NextGen- erationEU/PRTR. This work has also been partially supported by the Spanish Ministry of Science and Innovation (PID2019-107255GB-C21/AEI/10.13039/501100011033).Peer ReviewedPostprint (author's final draft

Balance de 25 años de jurisprudencia de la Corte Constitucional

La Corte Constitucional de Colombia ha tenido un importante impacto en la vida social, cultural y política del país, a tal punto que, desde su creación, la jurisprudencia de este tribunal se ha convertido en un referente mundial acerca de las diversas materias sobre las que se ha pronunciado . Este libro presenta un balance de la jurisprudencia que durante sus primeros veinticinco años la Corte ha expedido. Con este fin, el magistrado Luis Guillermo Guerrero Pérez y los magistrados auxiliares Miguel Polo Rosero y Claudia Escobar García recogen los trabajos de expertos nacionales e internacionales, funcionarios del Estado y Miembros de la sociedad civil que se presentaron en el XII Encuentro de la Jurisdicción Constitucional, realizado en la ciudad de San Juan de Pasto entre el 27 y el 30 de septiembre de 2017. En ese encuentro, se ratificó que la Corte Constitucional tiene la tarea de velar por la integridad de los compromisos de la Constitución. Los capítulos que conforman este libro ofrecen una mirada multidisciplinaria sobre la eficacia y el impacto de las decisiones de la Corte, específicamente en lo que tiene que ver con la democracia y la participación, el sistema de salud, el sistema pensional, el medio ambiente y el fenómeno discriminatorio con la relación al género y a la condición de discapacidad en Colombia.Bogot

A new IUPAC-consistent approach to the limit of detection in partial least-squares calibration

There is currently no well-defined procedure for providing the limit of detection (LOD) in multivariate calibration. Defining an estimator for the LOD in this scenario has shown to be more complex than intuitively extending the traditional univariate definition. For these reasons, although many attempts have been made to arrive at a reasonable convention, additional effort is required to achieve full agreement between the univariate and multivariate LOD definitions. In this work, a novel approach is presented to estimate the LOD in partial least-squares (PLS) calibration. Instead of a single LOD value, an interval of LODs is provided, which depends on the variation of the background composition in the calibration space. This is in contrast with previously proposed univariate extensions of the LOD concept. With the present definition, the LOD interval becomes a parameter characterizing the overall PLS calibration model, and not each test sample in particular, as has been proposed in the past. The new approach takes into account IUPAC official recommendations, and also the latest developments in error-in-variables theory for PLS calibration. Both simulated and real analytical systems have been studied for illustrating the properties of the new LOD concept.Fil: Allegrini, Franco. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química de Rosario (IQUIR-CONICET); ArgentinaFil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química de Rosario (IQUIR-CONICET); ArgentinaFil: Allegrini, Franco. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química de Rosario (IQUIR-CONICET); Argentina.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química de Rosario (IQUIR-CONICET); Argentina

Optimization of the hydrolysis of lignocellulosic residues by using radial basis functions modeling and particle swarm optimization

The concentrations of glucose and total reducing sugars obtained by chemical hydrolysis of three different lignocellulosic feedstocks were maximized. Two response surface methodologies were applied to model the amount of sugars produced: (1) classical quadratic least-squares fit (QLS), and (2) artificial neural networks based on radial basis functions (RBF). The results obtained by applying RBF were more reliable and better statistical parameters were obtained. Depending on the type of biomass, different results were obtained. Improvements in fit between 35% and 55% were obtained when comparing the coefficients of determination (R²) computed for both QLS and RBF methods. Coupling the obtained RBF models with particle swarm optimization to calculate the global desirability function, allowed to perform multiple response optimization. The predicted optimal conditions were confirmed by carrying out independent experiments.Fil: Giordano, Pablo César. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Cátedra de Química Analítica I. Laboratorio de Desarrollo Analítico y Quimiometría (LADAQ); Argentina.Fil: Giordano, Pablo César. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Fermentaciones; Argentina.Fil: Beccaria, Alejandro José. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Fermentaciones; Argentina.Fil: Goicoechea, Héctor Casimiro. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Cátedra de Química Analítica I. Laboratorio de Desarrollo Analítico y Quimiometría (LADAQ); Argentina.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química de Rosario (IQUIR-CONICET); Argentina

Exploration of liquid chromatographic-diode array data for Argentinean wines by extended multivariate curve resolution

Second-order data were measured using high-performance liquid-chromatography with diode array detection (HPLC-DAD) for a number of wine samples, which were directly injected in the HPLC-DAD system without sample pre-treatment. The data were arranged in data matrices whose modes were elution time and UV?visible absorption wavelength, and processed by extended multivariate curve resolution coupled to alternating least squares(MCR?ALS). The individual data matrices were organized in a row-wise augmented data matrix sharing the time subspace, due to the high spectral similarity among several sample components. This required previous time alignment of the chromatograms using a suitable synchronization algorithm, in order to produce a bilinear augmented datamatrix to be processed by MCR?ALS. The latter algorithm led to resolved component chromatogramsand spectra, from which component scores could be estimated, which are proportional to the relative component concentrations in each studied sample. The matrix of sample scoreswas then submitted to principal component analysis, which was applied for data exploration according to grape varietal and geographical origin. The results showed that the present data generation and analysis are useful for the discrimination of all samples of the Malbec varietal from the remaining ones, but achieved partial success regarding geographical origin.Fil: Pisano, Pablo Luis. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Silva, María Fernanda. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza (IBAM-CONICET); Argentina.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina

Second-order advantage obtained from standard addition first-order instrumental data and multivariate curve resolution-alternating least squares : calculation of the feasible bands of results

In order to achieve the second-order advantage, second-order data per sample is usually required, e.g., kinetic-spectrophotometric data. In this study, instead of monitoring the time evolution of spectra (and collecting the kinetic-spectrophotometric data) replicate spectra are used to build a virtual second order data. This data matrix (replicate mode k) is rank deficient. Augmentation of these data with standard addition data [or standard sample(s)] will break the rank deficiency, making the quantification of the analyte of interest possible. The MCR-ALS algorithm was applied for the resolution and quantitation of the analyte in both simulated and experimental data sets. In order to evaluate the rotational ambiguityin the retrieved solutions, the MCR-BANDS algorithm was employed. It has been shown that the reliability of the quantitative results significantly depends on the amount of spectral overlap in the spectral region of occurrence of the compound of interest and the remaining constituent(s).Fil: Mohseni, Naimeh. Urmia University. Faculty of Chemistry. Department of Analytical Chemistry; Iran.Fil: Bahram, Morteza. Urmia University. Faculty of Chemistry. Department of Analytical Chemistry; Iran.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Farhadi, Khalil. Urmia University. Faculty of Chemistry. Department of Analytical Chemistry; Iran

Chemometric modeling of organic contaminant sources in surface waters of a mediterranean river basin (Catalonia) district

Chemometric methods are applied to the analysis and interpretation of large multivariate data sets obtained in environmental monitoring studies. Concentrations of multiple organic compounds were measured in river samples taken from several sampling sites, at various geographical locations, during a number of campaigns and/or sampling time periods. Samples were collected and analyzed as part of an extensive multi-annual monitoring program from a mediterranean river basin (in Catalonia, at the northeast of Spain) by the Water Catalan Agency. Due to the great amount of multivariate data stored in environmental databases and to their complexity, chemometric modeling methods like Principal Components Analysis (PCA) and Multivariate Curve Resolution with Alternating Least-Squares (MCR-ALS) coupled to appropriate mapping representations are proposed for the evaluation of the environmental quality of the studied rivers. Results achieved in this study are intended to be a contribution to water quality assessment and evaluation of contamination of surface waters in Catalonia, and to support public policies of environmental control and management in the region under study.Fil: García Reiriz, Alejandro Gabriel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Teixidó, Elisabeth. Agència Catalana de l'Aigua; España.Fil: Ginebreda, Antoni. Instituto de Diagnóstico Ambiental y Estudios del Agua. Departamento de Química Ambiental (IDAEA-CSIC); España.Fil: Tauler, Romà. Instituto de Diagnóstico Ambiental y Estudios del Agua. Departamento de Química Ambiental (IDAEA-CSIC); España

A Critical Review on the Development of Optical Sensors for the Determination of Heavy Metals in Water Samples. The Case of Mercury(II) Ion

Recent publications are reviewed concerning the development of sensors for the determination of mercury in drinking water, based on spectroscopic methodologies. A critical analysis is made of the specific details and figures of merit of the developed protocols. Special emphasis is directed to the validation and applicability to real samples in the usual concentration range of mercury, considering the maximum allowed limits in drinking water established by international regulations. It was found that while most publications describe in detail the synthesis, structure, and physicochemical properties of the sensing phases, they do not follow the state of the art in the analytical developments. Recommendations are provided regarding the proper method development and validation, including the setting of the calibration concentration range, the correct estimation of the limits of detection and quantitation, the concentration levels to be set for producing spiked water samples, the number of real samples for adequate validation, the comparison of the developed method with a reference technique, and other analytical features which should be followed.Fil: Escandar, Graciela Mónica. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina.Fil: Olivieri, Alejandro César. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica. Instituto de Química Rosario (IQUIR-CONICET); Argentina