ABSTRACT: The objective of the research was to identify cocoa plots with the presence of glyphosate and 2,4-dichlorophenoxyacetic acid and to quantify these molecules in soils, leaves and dry fermented cocoa beans in 16 cocoa (Theobroma cacao L.) producing areas in the San Martin region. The samples were analyzed by ultra high performance liquid chromatography (UHPLC). Glyphosate concentrations in soils ranged from 0.1751 to 0.5925 ppm, while concentrations in cocoa leaves ranged from 0.0015 to 0.2639 ppm. In dry fermented cocoa beans, glyphosate values between 0.0427 and 0.5518 ppm were obtained. Regarding 2,4-dichlorophenoxyacetic acid values, soil concentrations ranged from 0.2248 to 0.7201 ppm; while in leaves, values between 0.0011 and 0.3307 ppm were reported. In dry cocoa beans, quantification ranged from 0.0708 to 0.6491 ppm. It was established that there are significant contrasts (p<0.05) between the amounts of glyphosate and 2,4-dichlorophenoxyacetic acid in soils, leaves and dry cocoa beans. The values of glyphosate and 2,4-dichlorophenoxyacetic acid found in dry cocoa beans in 93.75% of the plots exceed the MRLs dictated by NTS No 128-2016/MINSA/DIGESA, which is 0.1 ppm for these analytes.

RESUMEN: El objetivo de la investigación se centró en identificar parcelas cacaoteras con presencia de glifosato y 2,4-diclorofenoxiacético; así como cuantificar estas moléculas en suelos, hojas y granos fermentados secos de cacao en 16 zonas productoras de cacao (Theobroma cacao L.) en la región San Martín. Las muestras se analizaron mediante cromatografía líquida de ultra alta resolución (UHPLC). Encontrándose concentraciones de glifosato en suelos entre 0,1751 y 0,5925 ppm; por su parte en hojas de cacao se encontraron concentraciones entre 0,0015 y 0,2639 ppm. En granos secos fermentados de cacao se obtuvieron valores de glifosato entre 0,0427 y 0,5518 ppm. En lo referente a valores de 2,4-diclorofenoxiacético, los suelos presentaron concentraciones desde 0,2248 hasta 0,7201 ppm; mientras que en hojas se reportaron valores entre 0,0011 y 0,3307 ppm. En granos secos de cacao la cuantificación fue desde 0,0708 hasta 0,6491 ppm. Se estableció que existen contrastes significativos (p < 0,05) entre las cantidades de glifosato y 2,4-diclorofenoxiacético en suelos, hojas y granos secos de cacao. Afinando que los valores de glifosato y 2,4-diclorofenoxiacético encontrados en granos secos de cacao en el 93,75% de las parcelas superan los LMR que dicta la NTS No 128-2016/MINSA/DIGESA que es de 0,1 ppm para dichos analitos.

Resumo Para garantir o abastecimento em tempo e ininterrupto de matérias-primas de plantas medicinais, são relevantes os métodos de cultivo de culturas de células vegetais, nomeadamente a produção de culturas de raízes vegetais. Neste trabalho, foi estudado o potencial geroprotetor de culturas de raízes de Hedysarum neglectum Ledeb e Panax ginseng C. A. Mey. Eles foram cultivados em condições in vitro pela transformação do rizoma (H. neglectum) e mudas de sementes (P. ginseng) com Agrobacterium rhizogenes 15834 Swiss. Para identificar o potencial geroprotetor, o método antimicrobiano de difusão em disco e a atividade antioxidante foram analisados por titulação de extratos de KMnO4 de raízes de plantas. A composição qualitativa e quantitativa foi analisada por cromatografia líquida de alta eficiência, cromatografia em camada delgada e cromatografia gasosa com espectrometria de massa. No decorrer do trabalho, foi constatada a presença de atividade antimicrobiana e antioxidante dos extratos de raízes de plantas. Substâncias biologicamente ativas contidas em extratos de raízes de H. neglectum Ledeb e P. ginseng C. A. Mey são caracterizadas pelo potencial geroprotetor, podendo atuar como fonte de antioxidantes naturais na nutrição funcional da orientação geroprotetora.

Abstract In order to ensure the timely and uninterrupted supply of medicinal plant raw materials, the methods of cultivation of plant cell cultures, namely, the production of plant root cultures, are relevant. In this paper, the geroprotective potential of Hedysarum neglectum Ledeb and Panax ginseng C. A. Mey root cultures is studied. They were cultured under in vitro conditions by transforming the rhizome (H. neglectum) and seed seedlings (P. ginseng) with Agrobacterium rhizogenes 15834 Swiss. To identify the geroprotective potential, the antimicrobial disc-diffusion method and the antioxidant activity were analyzed by titration of KMnO4 extracts of plant root cultures. The qualitative and quantitative composition was analyzed using high-performance liquid chromatography, thin-layer chromatography, and gas chromatography with mass spectrometry. In the course of the work, the presence of antimicrobial and antioxidant activity of plant root culture extracts was established. Biologically active substances contained in extracts of Hedysarum neglectum Ledeb root crops and Panax ginseng C. A. Mey are characterized by geroprotective potential, so they can act as a source of natural antioxidants in the functional nutrition of the geroprotective orientation.

Resumo As perdas de alimentos por contaminação causada por fungos são de grande impacto negativo para a agricultura, gerando altos prejuízos econômicos. Para evitar as perdas de diversos produtos alimentícios pela contaminação fúngica são utilizados fungicidas sintéticos e naturais. As espécies do gênero Capsicum são usadas há muitos anos para auxiliar na conservação de alimentos por possuírem substâncias químicas com ação antifúngica entre outras. Neste contexto, o objetivo deste estudo foi identificar alguns compostos fenólicos por cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial (LC-ESI-MS/MS) presentes nos extratos acetato de etila (EAE) e metanólico (ME) dos frutos maduros da pimenta biquinho (C. chinense) e avaliar atividade antifúngica de EAE e ME contra os fungos Sclerotinia sclerotiorum, Rhizopus stolonifer e Colletotrichum gloeosporioides. Os extratos foram obtidos de forma sequencial, utilizando o procedimento de maceração. A atividade antifúngica foi avaliada seguindo a metodologia de difusão em disco, nas doses de 25 µL, 50 µL, 100 µL e 200 µL de cada extrato diluído. A análise química evidenciou a presença de ácido protocatequico, ácido gentisico, ácido vanílico, kaempferol-3-O-robinobiosídeo e naringenina em ambos os extratos. EAE revelou maior poder de inibição do crescimento micelial nas doses de 100µL e 200µL contra os três fungos testados, enquanto ME exibiu fraca atividade inclusive na maior dose investigada. Entretanto, estudos mais aprofundados ainda são necessários para consolidar seu uso e aplicação prática na área agronômica.

Abstract Food loss due to contamination caused by fungi has much impact on agriculture and leads to significant economic losses. Synthetic and natural fungicides have been used for avoiding losses of several food products due to fungal contamination. As a result, species of the genus Capsicum have been used for preserving food because of their chemical compounds with antifungal activity. Therefore, this study aimed at identifying some phenolic compounds found in both ethyl acetate extract (EAE) and methanolic extract (ME) from habanero pepper (C. chinense) ripe fruit by liquid chromatography tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS) and at evaluating their antifungal activities against fungi Sclerotinia sclerotiorum, Rhizopus stolonifer and Colletotrichum gloeosporioides. Extracts resulted from a sequential process of maceration. Antifungal activity was evaluated by the disk diffusion method (DDM) at the following doses of both diluted extracts: 25 µL, 50 µL, 100 µL and 200 µL. The chemical analysis showed that there were protocatechuic acid, gentisic acid, vanillic acid, kaempferol-3-O-robinobiosideo and naringenin in both extracts. EAE showed high inhibition of mycelial growth at both doses 100µL and 200µL against the three fungi while methanolic exhibited weak activity even at the highest dose under investigation. However, further in-depth studies are needed to reinforce their uses and practical applications to the agricultural field.

Resumo Dezessete sementes de variedades e clones de tamareiras foram avaliadas quanto aos seus componentes químicos e às propriedades do óleo de caroço de tâmara. A cromatografia gasosa líquida mostrou que o principal ácido graxo insaturado foi o ácido oleico (46,00% - 50,87%), enquanto o principal ácido graxo saturado foi o ácido láurico (10,11% - 19,03%) para as cultivares MTN e KBN, respectivamente; outros ácidos graxos também foram identificados. A caracterização físico-química mostrou um valor ácido variando de 0,068% a 1,188%, um valor específico de extinção igual a (K232: 1,350–2,225; K270: 0,318–0,521), um valor de peróxido no intervalo (1,059–5,618 meq O2/kg) e um valor de iodo (41,861–59,980 g Iodo/100 g). O teor de feofitina dos óleos de sementes de tâmara foi encontrado na faixa de 21,855% a 75,685%. A análise química mostrou que o óleo de semente de tâmara pode ser útil no processamento de produtos cosméticos e alimentícios.

Abstract This research was aimed to study the lipid fraction of date seeds. Seventeen seeds of date palm varieties and clones were evaluated and assessed for their chemical components and for the properties of the date pits oil. Gas liquid chromatography showed that the main unsaturated fatty acid was oleic acid (46.00 - 50.87%), while the main saturated fatty acid was lauric acid (10.11 - 19.03%) for the cultivars Mentouj Tissgharine (MTN) and Bheir Ingli (KBN) respectively; other fatty acids were also identified. The physicochemical characterization showed an acid value ranging from 0.068 to 1.188%, a specific extinction value equal to (K232: 1.350–2.225; K270: 0.318– 0.521), a peroxide value in the interval (1.059–5.618 meq O2/kg) and an iodine value (41.861–59.980 g Iodine/100 g). The pheophytin content of date seed oils was found within the range from 21.855 to 75.685%. The chemical analysis showed that date seed oil can be useful in cosmetic and food products processing.

Abstract New natural reducing agents with a lower negative impact on the environment and with a high antimicrobial potential are required for the process of obtaining silver nanoparticles through the chemical reduction method. The use of plant extracts can be a fast track in the formation of nanoparticles. In this case, organic compounds such as terpenes, flavonoids, enzymes, proteins, and cofactors present in plants act as reducing agents for nanomaterials. This research evaluated the antimicrobial property of silver nanoparticles from extracts of Crescentia cujete L. The presence of quercetin (flavonoid) was determined by high-performance liquid chromatography (HPLC); the production of silver nanoparticles (AgNPs) was established by green synthesis; the size and morphology of the nanomaterials were evaluated by scanning electron microscope (SEM). The antimicrobial capacity was studied by two analysis methods: modified culture medium and surface seeding. The presence of quercetin (26.55 mg L-1) in the crude extract of Crescentia cujete L., identified by HPLC, was evidenced. Nanoparticle formation was spherical, with an average size of 250 ± 3 and 460 ± 6 nm. Microbiological cultures with treatment showed 94% microbial inhibition. It was concluded that the Crescentia cujete L., leaves shoed an acceptable concentration of quercetin to be used as a useful adjuvant to enhance the reduction of NPs synthesis. The nanoparticles produced by green synthesis proved to have a positive effect to combat pathogenic microorganisms.

Resumo Novos agentes redutores naturais com menor impacto negativo ao meio ambiente e com alto potencial antimicrobiano são necessários para o processo de obtenção de nanopartículas de prata, pelo método de redução química. O uso de extratos vegetais pode ser um caminho rápido na formação de nanopartículas. Nesse caso, compostos orgânicos como terpenos, flavonoides, enzimas, proteínas e cofatores presentes nas plantas atuam como agentes redutores dos nanomateriais. Esta pesquisa avaliou a propriedade antimicrobiana de nanopartículas de prata de extratos de Crescentia cujete L. A presença de quercetina (flavonoide) foi determinada por cromatografia líquida de alta eficiência (HPLC); a produção de nanopartículas de prata (AgNPs) foi estabelecida por síntese verde; o tamanho e a morfologia dos nanomateriais foram avaliadas dos por microscópio eletrônico de varredura (SEM). A capacidade antimicrobiana foi estudada por dois métodos de análise: meio de cultura modificado e semeadura em superfície. Foi evidenciada a presença de quercetina (26,55 mg L-1) no extrato bruto de Crescentia cujete L., identificada por HPLC. A formação das nanopartículas foi esférica, com tamanho médio de 250 ± 3 e 460 ± 6 nm. Culturas microbiológicas com tratamento mostraram 94% de inibição microbiana. Assim, concluiu-se que as folhas de Crescentia cujete L. apresentam uma concentração aceitável de quercetina para ser utilizada como um adjuvante útil para potencializar a redução da síntese de NPs. As nanopartículas produzidas pela síntese verde provaram ter um efeito positivo no combate a microrganismos patogênicos.

Abstract The use of tank mixtures of pesticides makes it possible to increase the efficiency of chemical treatment. The aim of the study was to establish the relationship between the joint use of pesticides and the rate of decomposition of active substances. The study was carried out on the crops of spring wheat, spring barley, peas, spring rapeseed, seed potato. Chemical treatments were carried out with insecticides and fungicides – the insecticide (imidacloprid and λ-cyhalothrin), suspension concentrate; the fungicide (propiconazole), emulsifiable concentrate; the insecticide (imidacloprid), soluble concentrate; the fungicide (copper sulfate tribasic), suspension concentrate. Determination of residual amounts of active substances of pesticides was carried out using methods of gas-liquid chromatography and high-performance liquid chromatography. The acceleration of decomposition of the active substance - imidacloprid on pea crops and spring rapeseed was caused by the combined use of the insecticide (imidacloprid) and the fungicide (propiconazole). The use of the fungicide (copper sulfate tribasic) in a tank mixture with the insecticide (imidacloprid and λ-cyhalothrin) on potatoes caused a slowdown in the decomposition of the active substances imidacloprid and λ-cyhalothrin. Also, there was a change in the level of intake by plant of active substances in the first three hours after spraying, when using tank mixtures, in comparison with the separate use of compounds. The data obtained on the change in the rate of decomposition of active substances of pesticides, when they are used together in mixtures, indicate the need to continue research in this area. In this regard, it is important to study the dynamics of the decomposition of individual active substances of pesticides in plant tissues when they are used in tank mixtures, it is also necessary to conduct research using compounds most commonly used in agricultural production.

Resumo A utilização de misturas em tanques de pesticidas permite aumentar a eficiência do tratamento químico. O objetivo do estudo foi estabelecer a relação entre a utilização conjunta de pesticidas e a taxa de decomposição das substâncias ativas. O estudo foi realizado nas culturas de trigo de primavera, cevada de primavera, ervilha, colza de primavera e batata-semente. Foram realizados tratamentos químicos com inseticidas e fungicidas − o inseticida (imidacloprida e valuetech-cialotrina), concentrado em suspensão; o fungicida (propiconazol), concentrado emulsionável; o inseticida (imidacloprida), concentrado solúvel; o fungicida (sulfato de cobre tribásico), concentrado em suspensão. A determinação das quantidades residuais de substâncias ativas dos pesticidas foi realizada utilizando métodos de cromatografia gás-líquido e cromatografia líquida de alta eficiência. A aceleração da decomposição da substância ativa – imidacloprida nas culturas de ervilhas e colza de primavera foi causada pela utilização combinada do inseticida (imidacloprida) e do fungicida (propiconazol). A utilização do fungicida (sulfato de cobre tribásico), que contém cobre, numa mistura de tanques com o inseticida (imidacloprida e valuetech-cialotrina) em batatas provocou um abrandamento da decomposição das substâncias ativas imidacloprida e valuetech-cialotrina. Além disso, verificou-se uma alteração no nível de ingestão por planta de substâncias ativas nas primeiras três horas após a pulverização, quando se utilizam misturas em tanques, em comparação com a utilização separada de compostos. Os dados obtidos sobre a alteração da taxa de decomposição das substâncias ativas dos pesticidas, quando utilizadas em conjunto em misturas, indicam a necessidade de prosseguir a investigação neste domínio. Por isto, é importante estudar a dinâmica da decomposição de substâncias ativas individuais de pesticidas nos tecidos vegetais quando são utilizados em misturas em tanques, e realizar pesquisas que empreguem compostos mais comuns na produção agrícola.

Abstract The aim of this study was to assess the in vitro ovicidal activity of an ethyl acetate extract from Arceuthobium vaginatum (EtOAc-E) and their subfractions (AvR5-AvR14) against Haemonchus contortus using the egg hatching inhibition (EHI) test. The EtOAc-E and subfractions were tested at 0.12-2.00 and at 0.015-2.0 mg/mL, respectively. Distilled water and methanol (2%) were used as negative controls and Thiabendazole (0.10 mg/mL) as a positive control. Treatments with a dependent effect on concentration were subjected to regression analysis to determine the effective concentrations (EC50 and EC90). The major secondary compounds present in the extract and subfractions were identified by high performance liquid chromatography (HPLC). The EtOAc-E and AvR9 exhibited the best ovicidal effect recording 97.5 and 100% of EHI at 0.25 mg/mL, respectively. The EtOAc-E and AvR9 displayed an EC50= 0.12 and 0.08 mg/mL, respectively. The HPLC analysis in the EtOAc-E and bioactive fractions indicated the presence of a polyphenol, glycosylated flavanones, quercetin glucoside, cinnamates, coumarin, cinnamic acid derivative, ferulic acid, coumarate, naringenin, protocatechuic acid and naringin. Results demonstrated that A. vaginatum extract and fraction is able to inhibit the egg hatch process of H. contortus and could be a viable option for the control of small ruminant haemonchosis.

Resumo O objetivo deste estudo foi avaliar a atividade ovicida in vitro de um extrato de acetato de etila de Arceuthobium vaginatum (EtOAc-E) e suas subfrações (AvR5-AvR14) contra Haemonchus contortus, utilizando-se o teste de inibição da eclosão de ovos (EHI). O extrato foi testado em 0.12-2.00 mg/mL, e as subfrações foram testadas em 0.15-2.0 mg/mL. Água destilada e metanol (2%) foram utilizados como controles negativos e Tiabendazol (0.10 mg/mL) como controle positivo. Os tratamentos com efeito concentração dependente foram submetidos à análise de regressão para determinação das concentrações efetivas (CE50 e CE90). Os principais compostos secundários, presentes no extrato e nas subfrações, foram identificados por cromatografia líquida de alta eficiência (HPLC). EtOAc-E e subfração AvR9 exibiram o melhor efeito ovicida, registrando-se 97.5 e 100% do EHI a 0.25 mg/mL, respectivamente. O EtOAc-E e AvR9 apresentaram CE50= 0,12 e 0,08 mg/mL, respectivamente. A análise por HPLC nas frações EtOAc-E e bioativas indicou a presença de um polifenol, flavanonas glicosiladas, glicosídeo de quercetina, cinamatos, cumarina, derivado de ácido cinâmico, ácido ferúlico, cumarato, naringenina, ácido protocatecuico e naringina. Os resultados demonstraram que extrato e frações de A. vaginatum são capazes de inibir o processo de eclosão dos ovos de H. contortus, podendo ser uma opção viável para o controle da hemoncose em pequenos ruminantes.

A new class of deep eutectic solvents (DES) was used in the extraction of levodopa (L-dopa) present in Mucuna cinerea, which has been termed “green” or “designer” solvents, with notable productive and economic/environmental benefits. The seeds of Mucuna cinerea were prepared and submitted to extraction with heating and agitation in a solvent mixture of DES with citric acid, urea, or glycerol. The extracts were analyzed by high performance liquid chromatography (HPLC) which confirmed the efficiency of DES in extracting L-dopa. These extractions were carried out to determine the L-dopa extracts in DES with regard to the induction of cellular response activity, demonstrating the synergy between L-dopa and DES. The DES-glycerol extract exhibited a higher proliferative activity than commercial L-dopa after 24 h of treatment. The human glandular kallikrein-1 gene (hGK3) demonstrated higher expression in the treatment with the DES-urea, while the G protein-coupled receptor kinase-6 gene (GRK6) showed higher expression for all extracts compared to commercial L-dopa, with a higher value obtained for DES glycerol, followed by DES urea extract. The DES extraction method is therefore promising and unprecedented, confirming its possible use in the replacement of expensive solvents, supporting the use of ecologically viable DES in the extractions of other plant species.

The occurrence of pharmaceuticals in various wastewater treatment plants (WWTPs) and their discharge into the surface water are existing global challenges. However, such challenges are more detrimental in developing countries due to the aging infrastructure and its vandalism influenced by poverty, resulting in the illegal breakdown of the WWTPs. This study investigated the presence of efavirenz, ibuprofen, naproxen, sulfamethoxazole, and trimethoprim in WWTPs. Ultrasound-assisted extraction (UAE) followed by solid-phase extraction (SPE) was used to extract these pharmaceuticals in sludge samples, with wastewater extracted with only the latter. This was followed with analysis using a high-performance liquid chromatography-photo-diode array detection system. Recoveries found after spiking the samples with analytes at different concentrations ranged from 56 to 117%. An antibiotic, sulfamethoxazole, was among the prominent drugs in untreated wastewater with its concentration reaching 77 ug L-1. All the analytes were detected in sludge samples, with naproxen having the highest concentration of 13.35 ng g-1. The pharmaceutical with the lowest removal efficiency (2-12%) in WWTPs was efavirenz, while other drugs were fairly removed from wastewater. Overall, the findings of this study indicate the dysfunctionality of selected WWTPs in the Eastern Cape province of South Africa due to the release of high amounts of pharmaceuticals into the surface water which can be detrimental to humans, animals, and aquatic life.

In this study, various cannabis-based products were analysed for their cannabidiol (CBD) and ∆-9-tetrahydrocannabinol (∆9-THC) content. Thirteen samples were analysed using proton nuclear magnetic resonance (1H NMR) spectroscopy, with a subset further analysed by high pressure liquid chromatography (HPLC). In South Africa, it is currently required that the amount of CBD present in a sales pack should not exceed 600 mg, with the maximum dose in an individual unit being 20 mg, while the concentration of ∆-9-THC in processed products should not exceed 0.1% w/w. This study found that 85% of the products analysed had some degree of incorrect labelling with respect to CBD and THC content. Significant amounts (>1% w/w) of ∆-9-THC were also detected in 23% of the products that were tested. This method was also applied to 6 Cannabis plant extracts, which are used in the production of some of the cannabis-based goods. The concentrations of CBD and THC in both the goods and extracts, as determined by NMR spectroscopy, were in good agreement with concentrations determined orthogonally by HPLC. Analysis by 1H NMR spectroscopy, in particular, is shown to be a rapid and robust method for detecting and quantifying CBD and ∆-9-THC in cannabis-based products.

We report on the detection of an organic pollutant mostly found in local streams and wastewater treatment plants, specifically on triclosan detected in the Umbogintwini Industrial Complex (UIC), located on the south coast of Durban, KwaZulu-Natal in South Africa. Triclosan was successfully extracted from effluent samples using molecularly imprinted membrane adsorbents (MIMs) before quantification and removal using high-performance liquid chromatography (HPLC). This was done through fabrication of a polyvinylidene fluoride polymer using selective microparticles and molecularly imprinted polymers by means of phase inversion and an immersion precipitation method which results in enhanced hydrophilicity and membrane performance. The optimisation of experimental parameters - i.e. contact time and sample size - was performed through different stages of analysis. The synthesised MIMs exhibited an outstanding adsorption efficiency of 97% for triclosan in relation to those of non-imprinted membranes (NIMs) and pristine membranes at 92% and 88%, respectively. The analytical method employed had limits of detection and quantification of 0.21 and 0.69 parts per billion (ppb or μg/L) in wastewater effluent, respectively. The obtained efficiency results show great potential for future use of membrane and molecular imprinting technology, and that MIMs can be adopted as adsorbents for water treatment. The fast and highly selective methodology presented in this work could also be employed for the examination of persistent organic pollutants in the future to combat water scarcity in South Africa. SIGNIFICANCE: The key finding of this work is the incorporation of molecularly imprinted polymers with a membrane adsorbent to improve the performance of the membrane. An unexpected finding was the existence of pollutants like triclosan in water within the boundaries of the KwaMakhutha community, near the human settlement. Among the MIMs, NIMs and bare membranes, higher removal efficiencies were displayed by the synthesised MIMs against the discovered pollutants. This work could open doors for advanced research in the community

Abstract. Red wine is distinguished by a high economic and cultural value and therefore, its reliable characterization is important to assess its quality and authentication. Currently, Mexican wine consumption is growing due to wine tourism initiatives, then the determination of the chemical profile of commercial selected samples of young and aged red wines produced at wineries from Queretaro and Aguascalientes was performed. Seventy-eight nonvolatile compounds were identified by ultra performance liquid chromatography coupled to mass spectrometry. Three main families of secondary metabolites (Flavonols, ellagitannins and anthocyanins) were quantified by differential pulse voltammetry using carbon screen printed electrodes (SPEs). Tempranillo aged wine from Vinos del Marqués, Queretaro, showed the highest content of total polyphenols and anthocyanins from the evaluated wine samples. This research contributes to the knowledge of the chemical profile of commercial selected samples from wineries that belong to Mexican wine routes in a consolidated and experimental stage.

Resumen. El vino tinto se distingue por un alto valor económico y cultural y, por lo tanto, su caracterización confiable es importante para evaluar su calidad y autenticación. Actualmente, el consumo de vinos mexicanos se encuentra en crecimiento debido a las iniciativas de enoturismo, por ello, se llevó a cabo la determinación del perfil químico de muestras comerciales seleccionadas de vinos tintos jóvenes y de conserva producidos en bodegas de Querétaro y Aguascalientes. Se identificaron setenta y ocho compuestos no volátiles mediante cromatografía líquida de alta resolución acoplada a espectrometría de masas. Tres familias principales de metabolitos secundarios (flavonoles, elagitaninos y antocianinas) fueron cuantificadas mediante voltamperometría de pulso diferencial utilizando electrodos serigrafiados (SPEs) de carbón. El vino Tempranillo conserva de Vinos del Marqués, Querétaro, mostró el mayor contenido de polifenoles totales y antocianinas de las muestras de vino evaluadas. Esta investigación contribuye al conocimiento del perfil químico de muestras comerciales seleccionadas de bodegas pertenecientes a las rutas del vino mexicano en etapa consolidada y experimental.

Abstract. Because of its large electrochemical window, acetonitrile (MeCN) is one of the most widely used solvents in electrochemistry. It is a suitable solvent for nonaqueous electrolytes that allows studies of cathodic and anodic processes, but electrolyte purification remains challenging. As received, the high-performance liquid chromatography (HPLC) grade is unsuitable for most electroanalytical applications. We present an approach to optimize the purification of HPLC-grade acetonitrile to yield a tetrabutylammonium perchlorate (TBAP)/MeCN electrolyte for experiments in nonaqueous media. We used cyclic voltammetry (CV) to show the background due to impurities and to guide the experimental design to a background current acceptable for CVs of a 1 mM typical concentration of a redox-active molecule. We use 3A molecular sieves, followed by distillation over CaH2 with a final treatment with Al2O3. The optimized procedure yields CH3CN with small background currents, increasing the signal-to-noise ratio and minimizing chemical complications over a wide potential window. Our approach includes discriminating between impurities in the solvent and electrolyte salts; for TBAP, we recrystallize from ethyl acetate and 95 % ethanol. The process and theoretical guidelines apply to other nonaqueous electrolytes dealing with electroactive impurities, including organic molecules, oxygen, and water.

Resumen. El acetonitrilo (MeCN) es uno de los disolventes más utilizados en electroquímica por su amplia ventana electroquímica. Es un disolvente adecuado para electrolitos no acuosos que permite estudiar procesos electroquímicos catódicos y anódicos. Sin embargo, para llevar a cabo estos estudios, es importante considerar la purificación del electrolito que sigue siendo un reto. Tal como se recibe, el acetonitrilo para cromatografía de alto rendimiento (HPLC, por las siglas en inglés) es inadecuado para la mayoría de las aplicaciones electroanalíticas. En este trabajo presentamos un método para optimizar la purificación del acetonitrilo grado HPLC y obtener un electrolito de perclorato de tetrabutilamonio, (TBAP)/MeCN. Utilizamos voltametría cíclica para determinar la corriente de fondo y diseñar una corriente residual aceptable para una concentración típica de 1 mM para una molécula con actividad electroquímica. Utilizamos tamices moleculares 3Å, seguidos de destilación sobre CaH2 y finalizamos con un tratamiento en Al2O3. El procedimiento optimizado produce CH3CN con pequeñas corrientes de fondo, aumentando la relación señal-ruido y minimizando las complicaciones químicas en una amplia ventana de potencial. Nuestro enfoque incluye la discriminación entre las impurezas del disolvente y en las sales del electrolito. Recristalizamos el TBAP con una mezcla de acetato de etilo y etanol al 95 %. El proceso y las directrices teóricas se pueden aplicar a otros electrolitos no acuosos con impurezas electroactivas, como moléculas orgánicas, oxígeno y agua.

An extraction phase based on hydrogel disks of polyvinyl alcohol and pectin was developed, characterized, and evaluated for the extraction of four endocrine disruptors (methylparaben, ethylparaben, propylparaben and butylparaben) in free form in human urine samples with subsequent determination by liquid chromatography coupled with a diode array detector (LC-DAD). The proposed hydrogel showed easy synthesis, was made of low-cost and non-toxic polymers, and showed that it has an amphiphilic character. Gels with lower swelling indexes (175%) and more concentrated dispersions of polymers (P20PC2.0) showed lower relative standard deviation (RSD) values. Under optimized solid phase extraction (SPE) conditions, the LC-DAD method presented limits of quantification of 0.1 µg mL1, accuracy values ranged from 101.3 to 118.2%, while the inter-assay precision ranged from 1.5 to 17.4%. In addition, the polyvinyl alcohol (PVOH)/pectin-based material presented the possibility of reuse at least 15 times, without presenting carryover effect and physical degradation. In this way, the hydrogel shows promise for the extraction of organic compounds with different polarities in biological matrices.

This review deals with two-dimensional liquid chromatography (2D-LC) separations encompassing target heart-cut (LC-LC), multiple heart-cut (mLC-LC), non-targeted comprehensive (LC × LC), and selective comprehensive (sLC × LC) analysis. It presents an overview of basic concepts and emphasizes the versatility of the applications gained by going from one-(1D) to two-dimensional (2D) separations. This review also discusses target analysis of achiral and chiral drugs for different applications and the use of 2D-LC in zonal bioaffinity chromatography. Advances in instrumental and column technologies have widened the application of LC × LC and sLC × LC separations, and we will discuss some of them.