Isaí Vázquez Garrido

Benzene (Bz), phenol (Phen), hydroquinone (HQ), and catechol (CAT) are volatile organic compounds (VOCs) (monoaromatic compounds) considered environmental contaminants as a consequence of human and industrial activities. Prolonged exposure affects human health, causing cancer and death. Researchers have developed and applied analytical methodologies in pretreatment samples and detection techniques to analyze these monoaromatic compounds at trace and ultra-trace concentration levels. The present study is focused on an in-depth review and comparative analysis of removal and extraction techniques, summarizing the sources (analytical matrix), interaction modes (analyte-sorbent) in extraction techniques, solid phase extraction (SPE), dispersive solid phase extraction (DSPE), magnetic solid phase extraction (MSPE), and microextraction techniques), and the determination methods (chromatographic and non-chromatographic) applied in the analysis of these monoaromatic compounds in complex matrices.

The benzodiazepines are essential drugs used in medicine for anxiolytic, sedative, and hypnotic effects. According to the World Health Organization, the benzodiazepines are the most prescribed hypnotic drugs in the last decade (2010 at time), and their inappropriate use can damage the environment and human health. The availability of efficient analytical methods is crucial for the determination of these drugs in a complex matrix such as biological samples in clinical settings. In the last decade, several methods have been developed and have been applied to the detection and determination of benzodiazepines or their derivates. The present manuscript reviews selective and sensitive methodologies based on chromatographic, electrophoretic, and electrochemical systems for the determination of benzodiazepines in biological samples, covering the time of the last years and providing detailed information on sample pretreatment and instrumental conditions.

Los esteroides anabólicos androgénicos (EAAs) son medicamentos derivados de la testosterona desarrollados con fines médicos, sin embargo, en los últimos años se ha observado un incremento importante en el uso no clínico de dichos fármacos en la población de 16 a 25 años, principalmente con la finalidad de destacar en la práctica de algún deporte o por cuestión estética, por otro lado, existe una preocupación cada vez mayor en el sector salud por el consumo no regulado de los mismos, debido a que lo anterior conlleva a alteraciones cardiovasculares, hormonales, sexuales, psicológicas, etc., en personas que los consumen de forma inadecuada, lo que conduce a un posible problema de salud pública.

Los hidrocarburos son esenciales como fuentes de energía, encontrándose en diversos combustibles como gasolina, diésel y queroseno. Dentro de los hidrocarburos encontramos los alcanos, alquenos y alquinos. Para nombrar estos compuestos, la Unión Internacional de Química Pura y Aplicada (IUPAC) establece reglas específicas. Los alcanos se nombran basándose en la longitud de la cadena de carbono y las ramificaciones presentes. La presente guía aborda el proceso para nombrar alcanos y describe 5 pasos principales: 1) la identificación de la cadena principal, 2) numeración de la cadena, 3) nombramiento de ramificaciones, 4) colocación de localizadores y 5) escritura del nombre en una sola palabra. Esta guía pretende ayudar a estudiantes de química a entender y aplicar correctamente la nomenclatura de alcanos, minimizando errores y mejorando el desempeño en cursos de química orgánica.

A simple, fast, and low-cost pre-concentration methodology based on the application of solid-phase extraction coupled to layered double hydroxides (LDHs) and capillary electrophoresis was developed for the determination of naproxen (NPX), diclofenac (DFC), and ibuprofen (IBP) in environmental sample waters. A systematic study of the LDH composition was designed, including the effects of interlayer anions (NO₃⁻, Cl⁻, CO₃²⁻, BenO⁻, and SDS⁻) and the effect of molar ratio (Mg:Al). The optimal composition of MgAl/Cl⁻-LDH (Mg:Al; 1.5:1.0) was coupled to an SPE system: pH (neutral pH), LDH amount (15 mg), and extraction capacity ranged from 79.71 to 83.11% for the three anti-inflammatory non-steroidal agents analyzed. A recovery rate of up to 80.87% was obtained when 0.01 M chloride acid in methanol was used as the eluent and 50 mL of sample was used. Under optimal conditions, the linear range of the calibration curve ranges from 18.02 to 200 μg L⁻¹, with limits of detection ranging from 6.03 to 18.02 μg L⁻¹ for the three NSAIDs. The precision of the methodology was evaluated in terms of inter- and intra-day repeatability, with %RSD < 10% in all cases. The proposed method was applied to analyze environmental water samples (bottle, tap, cistern, well, and river water samples). The developed method is a robust technique capable of combining with other analytical methods to quantitatively determine anti-inflammatory non-steroidal agents.

La impresión molecular se fundamenta en la creación sintética de un material polimérico altamente entrecruzado alrededor de una determinada molécula molde y puede describirse como una unión específica entre una molécula determinada y el denominado receptor molecular. Los materiales molecularmente impresos son herramientas indispensables en numerosas aplicaciones actuales, en las cuales la elevada selectividad y especificidad características del reconocimiento molecular son aprovechadas. Una de las aplicaciones de mayor interés es en el tratamiento de la contaminación medioambiental, causada por la presencia de numerosas especies químicas como son: fármacos y sus metabolitos, aditivos industriales, metales pesados, pesticidas, etc. En el presente artículo se muestran ejemplos donde los materiales molecularmente impresos han sido utilizados en diversas muestras ambientales demostrando ser una potencial alternativa en el tratamiento selectivo de la contaminación.

The use of pesticides in the agricultural industry has been a recurrent practice for decades. Their inappropriate use causes residues of these compounds that can damage both environment and human health. Their analysis is crucial to determine their effects in the environment, while the food industry guarantees consumer safety. The composition of the analytical matrix is a critical factor to determine the viability of the selection and application of specific sample treatment techniques. The selection of an adequate sample treatment technique is necessary to remove interferences, minimising analyte loss, sample manipulation, allowing an adequate separation, extraction, isolation and pre-concentration. The present manuscript summarises the use of carbonaceous materials in synthesis, characterisation, theoretical studies, and their application to several sample pretreatment techniques coupled with instrumental techniques in the determination of pesticides on environmental, food and water samples. The incorporation of carbonaceous materials during the synthesis and development of new adsorbents provides specific interactions (pesticide-adsorbents) that improve the recognition properties, allowing innumerable advantages in terms of cost, performance, selectivity and analytical sensitivity in comparison with other adsorbents.