Immobilization of Acetylcholinesterase on Screen-Printed Electrodes. Application to the Determination of Arsenic(III)

Enzymatic amperometric procedures for measuring arsenic, based on the inhibitive action of this metal on acetylcholinesterase enzyme activity, have been developed. Screen-printed carbon electrodes (SPCEs) were used with acetylcholinesterase covalently bonded directly to its surface. The amperometric response of acetylcholinesterase was affected by the presence of arsenic ions, which caused a decrease in the current intensity. The experimental optimum working conditions of pH, substrate concentration and potential applied, were established. Under these conditions, repeatability and reproducibility of biosensors were determined, reaching values below 4% in terms of relative standard deviation. The detection limit obtained for arsenic was 1.1 × 10−8 M for Ach/SPCE biosensor. Analysis of the possible effect of the presence of foreign ions in the solution was performed. The method was applied to determine levels of arsenic in spiked tap water samples.Junta de Castilla y León (BU022A07, Q0968272E) and the Ministerio de Ciencia e Innovación (TEC2008-01367/TEC) is gratefully acknowledged

La política criminal en materia electoral: los desafíos para la democracia y la integridad de los procesos electorales en España y México

Esta investigación se centra en el análisis de la política criminal en materia electoral en México y España. Se pretende examinar el financiamiento ilegal de partidos políticos y cómo está relacionado con la corrupción, y establecer las medidas que han sido adoptadas en ambos países para reducir esta actividad ilegal. Además, el trabajo busca identificar los desafíos más urgentes en el ámbito de la política criminal electoral y establecer las medidas adecuadas para abordarlos. La metodología utilizada incluye el análisis de casos de México y España y una combinación de métodos descriptivos y analíticos. El objetivo final es contribuir a la discusión sobre la política criminal electoral y establecer una base para una política criminal electoral adecuada en ambos países.This research focuses on the analysis of criminal policy in electoral matters in Mexico and Spain. It aims to examine the illegal financing of political parties and how it is related to corruption, and to establish the measures that have been taken in both countries to reduce this illegal activity. In addition, the work seeks to identify the most urgent challenges in the field of criminal electoral policy and establish the appropriate measures to address them. The methodology used includes the analysis of cases in Mexico and Spain and a combination of descriptive and analytical methods. The final goal is to contribute to the discussion on criminal electoral policy and establish a basis for an appropriate criminal electoral policy in both countries

Optimization of a headspace solid-phase microextraction and gas chromatography/mass spectrometry procedure for the determination of aromatic amines in water and in polyamide spoons

In this work, a headspace solid-phase microextraction and gas chromatography coupledwith mass spectrometry (HS-SPME-GC/MS) method for trace determination of primary aromatic amines was developed. The following analytes were investigated: aniline (A), 4,4′-diaminodiphenylmethane (4,4′-MDA) and 2,4-diaminotoluene (2,4-TDA) using 3-chloro-4-fluoroaniline (3C4FA) and 2-aminobiphenyl (2ABP) as internal standards. Prior to extraction the analytes were derivatized in the aqueous solution by diazotation and subsequent iodination. The derivativeswere extracted byHS-SPME using a PDMS/DVB fiber and analyzed by GC/MS. A D-optimal design was used to study the parameters affecting the HS-SPME procedure and the derivatization step. Two experimental factors at two levels and one factor at three levels were considered: (i) reaction time, (ii) extraction temperature, and (iii) extraction time in the headspace. The interaction between the extraction temperature and extraction time was considered in the proposed model. The loadings in the sample mode estimated by a PARAFAC (parallel factor analysis) decomposition for each analyte were the response used in the design because they are proportional to the amount of analyte extracted. The optimum conditions for the best extraction of the analytes were achieved when the reaction time was 20 min, the extraction temperature was 50 °C and the extraction time was 25 min. The interaction was significant. A calibration based on a PARAFAC decomposition provided the following values of decision limit (CCα): 1.07 μgL−1 for A, 1.23 μg L−1 for 2,4-TDA and 0.83 μg L−1 for 4,4′-MDA for a probability of false positive fixed at 5%. Also, the accuracy (trueness and precision) of the procedurewas assessed. Furthermore, all the analyteswere unequivocally identified. Finally, the method was applied to spiked water samples and polyamide cooking utensils (spoons). 3% (w/v) acetic acid in aqueous solution was used as food simulant for testing migration from polyamide kitchenware. Detectable levels of 4,4′-diaminodiphenylmethane and aniline were found in food simulant from some of the investigated cooking utensils.Ministerio de Economía y Competitividad (CTQ2011-26022) and Junta de Castilla y León (BU108A11-2

Fluorescence determination of cochineal in strawberry jam in the presence of carmoisine as a quencher by means of four-way PARAFAC decomposition

The determination of cochineal (E-120) in strawberry jam was carried out in the presence of carmoisine (E-122) using the four-way PARAFAC decomposition and excitation-emission fluorescence matrices. In the measured conditions, there was no fluorescence signal for carmoisine due to a strong quenching effect and this colorant also led to a decrease of the fluorescence signal of cochineal. The European Union has fixed a maximum residue level, MRL, for cochineal in jam (100 mg kg−1). Therefore, the addition of other food colorant (carmoisine) in the jam could lead to false compliant decisions. The four-way PARAFAC decomposition avoided false compliant decisions caused by the quenching effect. Cochineal was unequivocally identified. Detection capability (CCβ) was 0.72 mg L−1 for probabilities of false positive and false negative fixed at 0.05. Cochineal was detected in the jam (104.63 mg kg−1) above the MRL. This amount was compared with the one obtained using a HPLC/DAD method.Spanish MINECO (AEI/FEDER, UE) through project CTQ2017‐88894-R and by Junta de Castilla y León through project BU012P17 (all co‐financed with European FEDER funds)

Determination of cochineal and erythrosine in cherries in syrup in the presence of quenching effect by means of excitation-emission fluorescence data and three-way PARAFAC decomposition

The simultaneous determination of two food colorants (cochineal (E-120) and erythrosine (E-127)) was achieved by means of excitation-emission fluorescence matrices and three-way PARAFAC decomposition together with the use of a calibration set that contained binary mixtures of both analytes. In the measured conditions, the amount of cochineal present in the sample affected the fluorescence signal of erythrosine since cochineal caused a quenching effect in the fluorescence of the other food additive. However, the signal of cochineal was not affected by the presence of erythrosine. A calibration line for erythrosine was built for each different concentration level of cochineal. The slopes of these regressions were different depending on the amount of quencher, whereas the intercepts were statistically equal to 0 at a 95% confidence level. The quantification of erythrosine was possible using the regression “amount of cochineal” versus “the slope of the calibration line for erythrosine”. Using this procedure, the mean of the absolute values of the relative errors in prediction for mixtures of both colorants were 5.86% (n = 10) for cochineal and 4.17% (n = 10) for erythrosine. Both analytes were unequivocally identified by the correlation between the pure spectra and the PARAFAC excitation and emission spectral loadings. Pitted cherries in syrup were analyzed. Cochineal and erythrosine were detected in those cherries at a concentration of 185.05 mg kg−1 and 10.76 mg kg−1, respectively. These concentration values were statistically equal to the ones obtained with a HPLC/DAD method.Spanish MINECO (AEI/FEDER, UE) through projects CTQ2014–53157-R and CTQ2017‐88894‐R and by Junta de Castilla y León through project BU012P1

Procedure to build a signal transfer set, independent of the target analytes, between a portable fluorimeter based on light-emitting diodes and a master fluorimeter

The need of performing “in situ” analytical determinations together with the availability of high-power deep UV-LEDs have led to the use of fluorescence spectroscopy. However, it is necessary to register excitation-emission matrices (EEM) to obtain three-way data which can be decomposed using parallel factor analysis for enabling the unequivocal identification of the analytes. In this context, the feasibility of transferring EEM between a portable fluorimeter based on LEDs and a master fluorimeter based on a xenon source has been recently reported without losing analytical quality. To build the transfer function, the signals of the same N samples must be recorded in the portable and in the master fluorimeter. In literature, these samples always contained the target analytes so the EEM signal transfer methodology is very limited in practice. Therefore, the challenge is to search for a set of samples whose EEM enable to perform the signal transfer without previously knowing the target analytes. The aim of this work is the design of a procedure to build N mixtures of P fluorophores so the N EEM would be optimal for the signal transfer. Five criteria have been defined a priori to identify the quality of a transfer set made up of N EEM. Then, a procedure has been designed to obtain the n mixtures of the P fluorophores “in silico” using the Pareto front of the optimal solutions and a desirability function to choose the desired N EEM. The procedure has been used to find five mixtures of the three chosen fluorophores for the signal transfer (coumarin 120, DL-Tyrosine and DL-Tryptophan) which are chemically different from the analytes of interest (enrofloxacin and flumequine) and are contained in a different matrix. These two analytes are antibiotics which have maximum residue limits set in the EU legislation in force. The correlation coefficients between the experimental reference spectra and the PARAFAC spectral loadings of the data registered with the master fluorimeter were greater than or equal to 0.999 in all cases. On the other hand, the correlation coefficients obtained with the portable fluorimeter ranged from 0.900 to 0.950 once the procedure was applied to the two antibiotics. Therefore, the unequivocal identification of the analytes was ensured.Spanish MINECO (AEI/FEDER, UE) through project CTQ2017‐88894‐R and by Junta de Castilla y León through project BU012P17 (all co‐financed with European FEDER funds)

Signal transfer with excitation-emission matrices between a portable fluorimeter based on light-emitting diodes and a master fluorimeter

In this work, the transfer of the excitation-emission matrices between a portable fluorimeter based on LEDs and a master fluorimeter based on a xenon source was carried out. Enrofloxacin was the analyte of interest and it was measured alone or in binary mixtures with flumequine (partially overlapped signals) or with ciprofloxacin (fully overlapped signals). The maintenance and transfer of the unequivocal identification of the fluorophores between both instruments are shown. The precision in the determination performed with the portable fluorimeter approximated to that made with the master fluorimeter using this transfer and it did not introduce bias. The correlation coefficients of the calibrations based on PARAFAC using EEM signals were higher than 0.999, whereas the values of the capability of detection ranged from 14.8 to 26.9 μg L−1 for probabilities of false positive and false negative fixed at 0.05. These results contribute to the effort to perform the fluorimetric detection outside the laboratory and to promote the use of databases of fluorescence spectra for the unequivocal identification in remote of fluorophores of interest and/or regulated.Spanish MINECO (AEI/FEDER, UE) through projects CTQ2014-53157-R and CTQ2017‐88894‐R and by Junta de Castilla y León through project BU012P17 (all co‐financed with European FEDER funds

Exactitud en las mediciones de las masas melanocíticas de fondo de ojo con dos diferentes retinógrafos según la localización de la masa

El melanoma de coroides es la neoplasia intraocular primaria más frecuente en la edad adulta. Su diagnóstico y tratamiento son fundamentales para mejorar la supervivencia y calidad de vida de los pacientes, así como para evitar una posible metástasis. La altura y el diámetro de las masas coroideas son factores clave para su diagnóstico y elección del mejor tratamiento.Existen diferentes técnicas de imagen para su detección y monitorización, siendo la ecografía y la retinografía las principales. Esta última, la retinografía, va a resultar de gran utilidad tras la nueva clasificación de los factores de riesgo de estas masas melanocíticas, además de presentar buena calidad de imagen, permite estudiar las masas en su totalidad y es técnicamente sencilla de utilizar. Sin embargo, también existen diferencias entre los diferentes sistemas de adquisición de retinografía, que hacen que nos planteemos si la medición y seguimiento de los melanomas y masas melanocíticas pueda presentar variabilidad.Por ello, el objetivo de este trabajo es evaluar si existen diferencias en las mediciones en función de la localización de las masas y en función del tamaño, comparando las imágenes obtenidas con el retinógrafo de campo amplio, CLARUS 700® y otro retinógrafo digital convencional, el de CANON® del Hospital Universitario Miguel Servet.<br /

Revisión bibliográfica sobre la validez y utilidad de la tomografía de coherencia óptica en las masas melanocíticas de pequeño tamaño en el fondo de ojo.

En cuanto a los nevus y los melanomas coroideos en ocasiones son clínicamente difíciles de diferenciar, principalmente aquellas lesiones con 2 mm de grosor, de este modo con técnicas no invasivas como la autofluorescencia (AF), la Retinografía, la ecografía y la tomografía de coherencia óptica (OCT) somos capaces de realizar un estudio de estas lesiones coroideas melanocíticas pequeñas.Estas técnicas de imagen para el diagnóstico de oncología ocular son unas técnicas muy valiosas a través de las cuales es posible detectar aquellos signos de riesgo que nos sirven para saber de la existencia de malignidad o no.Esos factores son conocidos con la regla actualizada de “To Find Small Ocular Melanoma Doing IMaging”.En el que cada signo tiene mayor fiabilidad con una determinada técnica, por lo que es conveniente poder realizar todas las técnicas mencionadas anteriormente y entre todas realizar un diagnóstico final. Priorizando de este modo el espesor mayor a 2 mm analizado por ecografía y OCT-EDI, el líquido subretiniano que se analiza por tomografía de coherencia óptica y por ecografía, los síntomas visuales mediante una evaluación clínica, el pigmento naranja por autofluorescencia, la sombra ecográfica del melanoma a través del ecógrafo y el diámetro del tumor mayor a 5 mm que se analiza a través de la retinografía y de la ecografía.Estas técnicas son todas unas técnicas que si se complementan entre ellas es posible llegar a un buen diagnóstico y seguimiento del tumor, dado que todas tienen sus limitaciones y sus ventajas, es decir el conjunto de estas técnicas multimodales son las que resultan más útiles para el diagnóstico de tumores oculares.<br /