Um método estável, confiável, eficiente com relação a tempo e custo para detecção de açúcares redutores, baseado no método colorimétrico do ácido dinitrossalicílico (DNS), adaptado para placas de microtitulação em um banho de água modificado com tratamento de microondas é proposto. Além da influência benéfica sobre o meio ambiente devido à redução do volume dos reagentes utilizados, o método modificado é rápido e permite a análise de um número relativamente alto de amostras. Pode ser aplicado em diversos tipos de laboratórios, de processamento de alimentos à indústrias farmacêuticas. O método adaptado foi parcialmente validado (intervalo de linearidade entre 7 µg e 5 mg per poço; limite de detecção 3 µg per poço, desvio padrão em torno de 5% para curvas de calibração com glucose, e recuperação superior a 90%) e aplicado à séries de produtos contendo açúcares redutores, como amostras de mel e vinho e medicamentos que contêm lactose como excipiente. O método proposto é bem adaptado como uma técnica de alto rendimento para determinação de açúcares redutores, pois todas amostras analisadas deram resultados esperados de acordo com as suas notas técnicas.A sound, reliable, time-and cost-efficient method for detection of reducing sugars, based on the well known dinitrosalicylic acid (DNS) colorimetric method, adapted for microtiter plates, in a modified water bath with microwave treatment is proposed. Besides the benefic influence on the environment due to the reduction of the volume of the reagents, the modified method is rapid and allows the analysis of a relatively high number of samples. It can be applied in many types of laboratories from food processing to pharmaceutical industries. The adapted method was partially validated (linearity range between 7 µg and 5 mg per well; limit of detection 3 µg per well, standard deviation around 5% for calibration curves with glucose, and a recovery higher than 90%) and applied to a series of products containing reducing sugars, such as honey, wine samples and drugs containing lactose as an excipient. The proposed method is well-suited as a high-throughput technique for determination of reducing sugars as all the analyzed samples gave the expected results according with their technical notes.Keywords: dinitrosalicylic acid (DNS), microtiter plate assay, microwave supported reaction, reducing sugars IntroductionMonosaccharides, most of oligosaccharides, glucose polymers, such as starch and cellulose, and copolymers, like chitin, contain reducing ends. The measurements of the concentration of reducing ends can give valuable information about the analyzed sample. 1 Especially due to their presence in many natural products, reducing sugars (RS) have received considerable attention, which lead to a growing number of methods for their assay. The ability to measure the concentration of RS bears much significance for understanding the amount of sugar in foodstuffs, in beverages and even, although indirectly, the activities of some enzymes which are responsible for the hydrolysis of po...

Given the modeling and predictive abilities of quantitative structure activity relationships (QSARs) for genotoxic carcinogens or mutagens that directly affect DNA, the present research investigates structural alert (SA) intermediate-predicted correlations ASA of electrophilic molecular structures with observed carcinogenic potencies in rats (observed activity, A = Log[1/TD50], i.e., ASA=f(X1SA,X2SA,…)). The present method includes calculation of the recently developed residual correlation of the structural alert models, i.e., ARASA=f(A−ASA,X1SA,X2SA,…). We propose a specific electrophilic ligand-receptor mechanism that combines electronegativity with chemical hardness-associated frontier principles, equality of ligand-reagent electronegativities and ligand maximum chemical hardness for highly diverse toxic molecules against specific receptors in rats. The observed carcinogenic activity is influenced by the induced SA-mutagenic intermediate effect, alongside Hansch indices such as hydrophobicity (LogP), polarizability (POL) and total energy (Etot), which account for molecular membrane diffusion, ionic deformation, and stericity, respectively. A possible QSAR mechanistic interpretation of mutagenicity as the first step in genotoxic carcinogenesis development is discussed using the structural alert chemoinformation and in full accordance with the Organization for Economic Co-operation and Development QSAR guidance principles.

The present work employs 152 benzene-carboxylic acid' esters having computed the toxicity within the range [2.251, 10.222] for fathead minnow fish (Pimephales promelas). Calibration set includes many pairs having very similar chemical structure, size, shape and hydrophilicity, but very different value of ECOSAR toxicity or vice versa. The QSTR study, which uses all esters as calibration set, emphasized a large percent (16.2%) of outliers. In this QSTR study most of the estimated values of toxicity for outliers are much lower than ECOSAR toxicity. The LogP and some aromaticity descriptors are predictors. The best QSTR for esters having low value (< 5.5) of ECOSAR toxicity and the best QSTR for esters having high value (> 5.5) of ECOSAR toxicity are obtained when the number of outliers is very small. These QSTRs are different enough and highlight opposite influences of certain descriptors on toxicity. The results emphasize two possibilities: (a) the esters having low value of ECOSAR toxicity and the esters having high value of ECOSAR toxicity are included in two different classes from the point of view of structure-toxicity relationship and/or (b) many high values of ECOSAR toxicity are wrong. By comparison, a QSTR using experimental values of toxicity against rats for 37 benzene-carboxylic esters included in the same database gives good correlation experimental/computed values of toxicity, the number of outliers is null and the result of validation test is good.

In this study, the concentrations of 15 phenol derivatives were analyzed from the phreatic and groundwater wells surrounding a decommissioned chemical factory in a village from the western part of Romania. An UPLC-MS method was used to assess the concentrations of the chemical target compounds in the water samples. The most frequent compounds were 4-chlorophenol, 4-tertoctylphenol and 4-nonylphenol, being detected in 17 of the 19 sampling sites, while the least frequent compound was 2,4,6trichlorophenol, that was found in only 7 samples. The highest mean concentration was obtained for bisphenol A (47.54 ngꞏmL -1 ), while 2,4-dinitrophenol was found with the lowest mean concentration (9.38 ngꞏmL -1 ). The most contaminated water samples were found in the monitoring wells placed downstream of the factory. With the exception of the samples taken from the municipal drinking water system, the samples from phreatic water wells contained the target phenol derivatives, at various concentrations. Although the platform has ceased completely, the hazard caused by decades of continuous phenolic pollutant leakage is still significant to the present day.