Synthesis,biological evaluation and DNA binding properties of novel mono and bisnaphthalimides

A novel series of mono and bisnaphthalimides was synthesized and their antiproliferative activities were evaluated against three tumor cell lines. Bisnaphthalimides 3 and 4, bearing a pyrazine ring fused to the naphthalimide system, showed activities in the order of 10(-8) microM, similar to elinafide. DNA binding properties and the ability to induce DNA damage were studied for some of the most active compounds.     

Development of a method for analyzing volatiles from foodstuff matrices,including microextraction by demixture. Application to the analysis of grapes

This paper presents a general method for analyzing volatiles from foodstuff samples, and its application to the analysis of grapes. The method includes steam stream distillation, microextraction and chromatographic analysis, and all aspects of the analysis, including sample treatment, are discussed. Data on recovery and reproducibility are given. The method allows to prepare samples for quantitative chromatographic analysis in only one hour and to quantitate the volatiles present in the original samples at concentrations between 0.2 and 2000 mg 1^–1 with FID detection.     

Spectrophotometric determination of nickel with 1-(1,2,4-triazolyl-3-azo)-2-naphthol with application to steel

Nickel(II) reacts with 1-(1,2,4-triazolyl-3-azo)-2-naphthol (TRAN) in aqueous 40% ethanol at pH 5 to form a red 1:2 complex having an absorption peak at 523 nm. The system conforms to Beer's Law in the range 0.2–2.8 ppm Ni(II). The molar absorptivity is 3.7 × 10⁴ l mol^-1 cm^-1. Various interferences can be avoided by extraction of the Ni(II)—TRAN complex into chloroform, which allows determinations of nickel in steels.     

Quantitative determination of wine highly volatile sulfur compounds by using automated headspace solid-phase microextraction and gas chromatography-pulsed flame photometric detection. Critical study and optimization of a new procedure

The quantitative determination of wine volatile sulfur compounds by automated headspace solid-phase microextraction (HS-SPME) with a carboxen-polydimethylsiloxane (CAR-PDMS) fiber and subsequent gas chromatography-pulsed flame photometric detection (GC-PFPD) has been evaluated. The direct extraction of the sulfur compounds in 5 ml of wine has been found to suffer from matrix effects and short linear ranges, problems which could not be solved by the use of different internal standards or by multiple headspace SPME. These problems were attributed to saturation of the fiber and to competitive effects between analytes, internal standards and other wine volatiles. Another problem was the oxidation of analytes during the procedure. The reduction in sample volume by a factor 50 (0.1 ml diluted with water or brine) brought about a reduction in the amount of sulfur compounds taken in the fiber by a factor just 3.3. Consequently, a new procedure has been proposed. In a sealed vial containing 4.9 ml of saturated NaCl brine, the air is thoroughly displaced with nitrogen, and the wine (0.1 ml) and the internal standards (0.02 ml) are further introduced with a syringe through the vial septum. This sample is extracted at 35 degrees C for 20 min. This procedure makes a satisfactory determination possible of hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, diethyl sulfide and dimethyl disulfide. The linear dynamic ranges cover the normal ranges of occurrence of these analytes in wine with typical r2 between 0.9823 and 0.9980. Reproducibility in real samples ranges from 10 to 20% and repeatability is better than 10% in most cases. The method accuracy is satisfactory, with errors below 20% for hydrogen sulfide and mostly below 10% for the other compounds. The proposed method has been applied to the analysis of 34 Spanish wines.     

Virtual Extensive Read-Across: A New Open-Access Software for Chemical Read-Across and Its Application to the Carcinogenicity Assessment of Botanicals

Read-across applies the principle of similarity to identify the most similar substances to represent a given target substance in data-poor situations. However, differences between the target and the source substances exist. The present study aims to screen and assess the effect of the key components in a molecule which may escape the evaluation for read-across based only on the most similar substance(s) using a new open-access software: Virtual Extensive Read-Across (VERA). VERA provides a means to assess similarity between chemicals using structural alerts specific to the property, pre-defined molecular groups and structural similarity. The software finds the most similar compounds with a certain feature, e.g., structural alerts and molecular groups, and provides clusters of similar substances while comparing these similar substances within different clusters. Carcinogenicity is a complex endpoint with several mechanisms, requiring resource intensive experimental bioassays and a large number of animals; as such, the use of read-across as part of new approach methodologies would support carcinogenicity assessment. To test the VERA software, carcinogenicity was selected as the endpoint of interest for a range of botanicals. VERA correctly labelled 70% of the botanicals, indicating the most similar substances and the main features associated with carcinogenicity.     

PREPARATION OF LARGE-PARTICLE-SIZE MONODISPERSE LATEXES IN SPACE: POLYMERIZATION KINETICS AND PROCESS DEVELOPMENT

Monodisperse polystyrene latexes are prepared by seeded emulsion polymerization; however, sizes larger than 2μm are difficult to prepare because of the creaming and settling of the particles, and their sensitivity to mechanical shear. Preparation in space would obviate the creaming and settling, and allow agitation just sufficient for good heat transfer and mixing. Three polymerizations yielding 3-5μm size particles were carried out successfully on the third flight of the “Columbia” launched March 22, 1982; however, four polymerizations yielding sizes up to 10μm on the fourth flight launched June 27, 1982, were incomplete owing to apparatus malfunction. The results of these polymerizations and the prospects of developing a preparative space process are reviewed     

Molecularly imprinted polymers: An analytical tool for the determination of benzimidazole compounds in water samples

Molecularly imprinted polymers (MIPs) for benzimidazole compounds have been synthesized by precipitation polymerization using thiabendazole (TBZ) as template, methacrylic acid as functional monomer, ethyleneglycol dimethacrylate (EDMA) and divinylbenzene (DVB) as cross-linkers and a mixture of acetonitrile and toluene as porogen. The experiments carried out by molecularly imprinted solid phase extraction (MISPE) in cartridges demonstrated the imprint effect in both imprinted polymers. MIP–DVB enabled a much higher breakthrough volume than MIP–EDMA, and thus was selected for further experiments. The ability of this MIP for the selective recognition of other benzimidazole compounds (albendazole, benomyl, carbendazim, fenbendazole, flubendazole and fuberidazole) was evaluated. The obtained results revealed the high selectivity of the imprinted polymer towards all the selected benzimidazole compounds.An off-line analytical methodology based on a MISPE procedure has been developed for the determination of benzimidazole compounds in tap, river and well water samples at concentration levels below the legislated maximum concentration levels (MCLs) with quantitative recoveries. Additionally, an on-line preconcentration procedure based on the use of a molecularly imprinted polymer as selective stationary phase in HPLC is proposed as a fast screening method for the evaluation of the presence of benzimidazole compounds in water samples.     

HPLC‐DAD methodology for the quantification of organic acids,furans and polyphenols by direct injection of wine samples

This article proposes a simple and sensitive HPLC method with photo‐diode array detection for the analysis of organic acids, monomeric polyphenols and furanic compounds in wine samples by direct injection. The chromatographic separation of 8 organic acids, 2 furans and 22 phenolic compounds was carried out with a buffered solution (pH 2.70) and acetonitrile as mobile phases and a difunctionally bonded C18 stationary phase, Atlantis dC18 (250×4.6 mm, 5 μm) column. The elution was performed in 12 min for the organic acids and in 60 min for the phenolic compounds, including phenolic acids, stilbenes and flavonoids. Target compounds were detected at 210 nm (organic acids, flavan‐3‐ols and benzoic acids), 254 nm (ellagic acid), 280 nm (furans and cinnamic acid), 315 nm (hydroxycinnamic acids and trans‐resveratrol) and 360 nm (flavonoids). The RSD for the repeatability test (n=5) of peak area and retention times were below 3.1 and 0.3%, respectively, for phenolics and below 1.0 and 0.2% for organic acids. The RSDs expressing the reproducibility of the method were higher than for the repeatability results but all below 9.0%. Method accuracy was evaluated by the recovery results, with averaged values between 80 and 104% for polyphenols and 97–105% for organic acids. The calibration curves, obtained by triplicate injection of standard solutions, showed good linearity with regression coefficients higher than 0.9982 for polyphenols and 0.9997 for organic acids. The LOD was in the range of 0.07–0.49 mg/L for polyphenols (cinnamic and gallic acids, respectively) and 0.001–0.046 g/L for organic acids (oxalic and lactic acids, respectively). The method was successfully used to measure and assess the polyphenolic fingerprint and organic acids profile of red, white, rosé and fortified wines.