Naphthalene Residues Research Articles

First evidence of marine diesel effects on biomarker responses in the Icelandic scallops, Chlamys islandica.

The decrease of ice cover in polar areas is expected to lead to an increase in ship traffic. In this context, the risk associated with exposure of the aquatic environment to oil-related chemicals from spills and/or accidental fuel discharges from ships will increase in the near future, potentially causing negative impacts on sensitive Arctic species. This study investigated for the first time the biomarker responses of the Icelandic scallops (Chlamys islandica) to marine diesel exposure. Antioxidant response, neurotoxic effect, gonad maturation, and lipid content were assessed in male and female scallops, Chlamys islandica after a 7-day exposure to marine diesel. At the end of exposure, results showed an inhibition of acetylcholinesterase activity in Icelandic scallops exposed to high concentration of diesel. At the end of exposure, results showed an increase in naphthalene residues in hemolymph, together with an inhibition of AChE activity in Icelandic scallops exposed to high concentration of diesel. In addition, alteration of the escape capacity was observed suggesting effects on behavior responses. Overall, this study contributes to the better knowledge of physiological effects of marine diesel in Arctic marine organisms.

Electrochemical Properties of Interstrand Cross-Linked DNA Duplexes Labeled with Nile Blue

DNA molecules have attracted considerable attention as functional materials in various fields such as electrochemical sensors with redox-labeled DNA. However, the recently developed interstrand cross-link (ICL) technique for double-stranded DNA can adequately modify the electronic properties inside the duplex. Hence, the electrochemical investigation of ICL-DNA helps us to understand the electron transfer of redox-labeled DNA at an electrode surface, which would develop useful sensors. In this study, the first insight into this matter is presented. We prepared 17-mer DNA duplexes incorporating Nile blue (NB-DNA) at one end as a redox marker and a disulfide tether at the other end for immobilization onto an electrode. The duplexes were covalently cross-linked by bifunctional cross-linkers that utilize either a propyl or naphthalene residue to replace a base pair. Their electrochemical responses at the electrode surface were compared to evaluate the effect of the ICL on the electron-transfer reactions of the redox-labeled DNA duplexes. A direct transfer of electrons between NB and the electrode was observed for a standard DNA, as previously reported, whereas interstrand cross-linked DNA (CL-DNA) strands showed a decrease in the direct electron-transfer pathway. This is expected to result from constraining the elastic bending/flexibility of the duplex caused by the covalent cross-links. Interestingly, the CL-DNA incorporating naphthalene residues exhibited additional voltammetric peaks derived from DNA-mediated electron transfer (through base π stacking), which was not observed in the mismatched CL-DNA. The present results indicate that the ICL significantly affects electron transfer in the redox-labeled DNA at the electrode and can be an important determinant for electrochemical signaling in addition to its role in stabilizing the duplex structure.

Assessment of Naphthalene Residues in Beeswax Foundations Stored in Windscreen Cabinets

Assessment of Naphthalene Residues in Beeswax Foundations Stored in Windscreen Cabinets

Analysis of Naphthalene Residues in Textile Samples by GC-FID Using Sol-Gel-Derived SPME Fiber

Solid-phase microextraction (SPME) coupled to gas chromatography (GC) has been developed for the analysis of naphthalene residues in five textiles samples using sol-gel-derived 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28diglycidyloxycalix[4]arene/hydroxy-terminated silicone oil fiber. The main parameters affecting extraction and desorption process such as temperature and time were optimized statistically. Compared with four commercial stationary phases and sol-gelderived OH-TSO SPME fiber, this fiber showed statistically highest enrichment capability for naphthalene in the textile sample. SPME‐GC‐flame ionization detection method showed good linearity for the tested concentration range with regression coefficient being 0.9996. Detection limits was 1.17 ng/g. Relative standard deviations ( n = 6) of method at three concentration levels of 1.0, 0.5, and 0.1 µg/g ranged between 1.1% and 5.4%, which provided good analytical precision. In addition, this fiber had satisfying fiber to fiber and batch to batch reproducibility. Recoveries for the analyte ranged from 78.3% to 102.7%. It indicated that this method developed was an efficient and accurate procedure for determination of naphthalene residues in textiles samples.

Solid-phase microextraction/gas-chromatographic/mass spectrometric analysis of p -dichlorobenzene and naphthalene in honey

Protection of honeycombs from the Wax moth, Galleria mellonella, involves the use of physical, biological or chemical control methods. As chemical control may result in residues in the extracted honey, the presence of p-dichlorobenzene and naphthalene residues was investigated by solid-phase microextraction (SPME) coupled to gas-chromatographic/mass spectrometry (GC/MS). The method was linear between 5 and 200 µg kg–1 honey for p-dichlorobenzene and 1 and 200 µg kg–1 for naphthalene. Limits of detection were 1 and 0.1 µg kg–1, respectively, for p-dichlorobenzene and naphthalene, while relative standard deviations were 2.6 and 7.9%, respectively. Application of the method to 90 unifloral Greek honeys revealed that, in 25.6% of the samples, the concentration of either one of the pesticides exceeded the maximum residue level (MRL). Maximum concentrations were 163.03 µg kg–1 honey for p-dichlorobenzene and 193.74 µg kg–1 honey for naphthalene. Naphthalene was found in traceable amounts in 78.9% of the samples, but only 5.6% of them contained concentrations above the MRL, which indicates the use of pre-contaminated honeycomb foundations or built combs. Nevertheless, because naphthalene is naturally present in some plant species growing in Greece, the contribution of nectar from such a floral source should not be overlooked.

Development of a rapid and sensitive method for the simultaneous determination of 1,2-dibromoethane, 1,4-dichlorobenzene and naphthalene residues in honey using HS-SPME coupled with GC–MS

A new method for the simultaneous determination of 1,4-dichlorobenzene ( p-DCB), naphthalene and 1,2-dibromoethane (1,2-DBE) residues in honey has been developed. Analysis is carried out using gas chromatography–mass spectrometry (GC/MS) in selected ion monitoring mode (SIM), after extraction and preconcentration of target analytes by headspace solid-phase microextraction (HS-SPME), with a 100 μm film thickness polydimethylsiloxane (PDMS) fiber. Several parameters affecting the extension of the adsorption process (i.e., addition of salt, extraction time, extraction temperature) were studied. The optimal conditions for the determination of these analytes were established. The proposed HS-SPME method showed good sensitivity, without carryover between the samples. Linearity was studied from 5 to 2500 μg kg −1 for p-DCB, 0.5 to 500 μg kg −1 for naphthalene and 5 to 500 μg kg −1 honey for 1,2-DBE with correlation coefficients ( r 2) ranging from 0.9901 to 0.9999. Precision was assessed and both intra and inter-day R.S.D.s (%) were below 6.3%. The detection limits were found to be 1, 0.1 and 2 μg kg −1 honey for p-DCB, naphthalene and 1,2-DBE, respectively. The percentage recoveries that were evaluated with the proposed HS-SPME method and the standard addition calibration technique gave values among 72.8 and 104.3% for measurements in samples spiked with one target analyte or mixtures of the three. This method has been applied for the analysis of unknown honey samples. The results showed an excellent applicability of the proposed method for the determination of the target compounds in honey samples.

Synthesis and Photophysical Properties of Borondipyrromethene Dyes Bearing Aryl Substituents at the Boron Center

Several borondipyrromethene (Bodipy) dyes bearing an aryl nucleus linked directly to the boron center have been prepared under mild conditions. The choice of Grignard or lithio organo-metallic reagents allows the isolation of B(F)(aryl) or B(aryl)2 derivatives; where aryl refers to phenyl, anisyl, naphthyl, or pyrenyl fragments. A single crystal, X-ray structure determination for the bis-anisyl compound shows that the sp3 hybridized boron center remains pseudo-tetrahedral and that the B-C bond distances are 1.615 and 1.636 A. All compounds are electrode active but replacement of the fluorine atoms by aryl fragments renders the Bodipy unit more easily oxidized by 100 mV in the B(F)(aryl) and 180 mV in the B(aryl)2 compounds whereas reduction is made more difficult by a comparable amount. Strong fluorescence is observed from the Bodipy fluorophore present in each of the new dyes, with the radiative rate constant being independent of the nature of the aryl substituent. The fluorescence quantum yields are solvent dependent and, at least in some cases (aryl = anisyl or pyrenyl), nonradiative decay from the first-excited singlet state is strongly activated. There is no indication, however, for population of a charge-transfer state, in which the aryl substituent acts as donor and the Bodipy fragment functions as acceptor, that is strongly coupled to the ground state. Instead, it is conjectured that nonradiative decay involves a conformational change driven by the solvophobic effect. Thus, the rate of nonradiative decay in any given solvent increases with increasing surface accessibility (or molar volume) of the aryl substituent. Intramolecular energy transfer from pyrene or naphthalene residues to Bodipy is quantitative.

Determination of 1,2-dibromoethane, 1,4-dichlorobenzene and naphthalene residues in honey by gas chromatography–mass spectrometry using purge and trap thermal desorption extraction

A highly sensitive method for the determination of 1,2-dibromoethane, 1,2-dichlorobenzene and naphthalene residues in honey was developed, using gas chromatography–mass spectrometry combined with a purge and trap thermal desorption system as the extraction technique. Optimal conditions for isolation and separation were established and calibration curves were constructed. Linearity was held between 2.4 and 300 μg kg −1 honey for 1,2-dibromoethane, 0.5 and 300 μg kg −1 for 1,4-dichlorobenzene and 0.125 and 3000 μg kg −1 for naphthalene. The detection limits were found to be 0.8, 0.15 and 0.05 μg kg −1 honey for 1,2-dibromoethane, 1,4-dichlorobenzene and naphthalene, respectively. The method was applied to the analysis of 25 Greek honey samples. 1,2-Dibromoethane was not found in the majority of the samples, while only one sample was found to contain both 1,4-dichlorobenzene and naphthalene residues at concentrations exceeding 10 μg kg −1.

Naphthalene degradation by Pseudomonas putida strains in soil model systems with arsenite

The effect of arsenite on the degradation of naphthalene, a polycyclic aromatic hydrocarbon (PAH), by P. putida strains BS202 (NPL-1) and BS238 (pBS2; pBS3031) was studied. Their resistance to arsenite is determined by either chromosomal or plasmid genes. In a soil model system supplied with arsenite (400 μg/g dry soil), the cell density of strain BS238 (pBS2; pBS3031), grown on naphthalene, remained virtually unaltered though naphthalene consumption was slightly delayed (1 day lag); naphthalene disappeared by the 6th day. Under the same experimental conditions, strain BS202 (NPL-1) was characterized by a long lag-phase during the first 2 days of cultivation and a slow consumption of naphthalene: by the 6th day naphthalene residues were still detectable in the soil model system. The effect of arsenite on naphthalene degradation by the PAH-degrading P. putida strains exhibiting different mechanisms of the arsenite resistance is discussed.

Aromaticity in benzene-like rings — An experimental electron density investigation

An experimental charge density study has been carried out on perylene based on X-ray diffraction measurements at 130 K. The electron density and its associated properties have been evaluated at the bond and the ring critical points for the naphthalene residues as well as for the central ring. The variation of the Laplacian along the axis, above and below the ring plane, is found to be symmetric for the central ring while for the naphthalene rings, the Laplacian values are enhanced under the bow-shaped region. A plot of the Laplacian versus density evaluated at various points along the axis above the ring plane, shows a steep variation in the case of the central ring implying that theπ-density is smeared out compared to that over the naphthalene rings. Similar data extracted from a quinoid ring and a regular phenyl ring (both based on earlier reports from this laboratory) exhibit increasingly shallower trends and indicate, by contrast, that the central ring of perylene is much less aromatic.

Polychlorinated Naphthalenes in Sediment and Biota from the Gdañsk Basin, Baltic Sea

To identify potential sources and accumulation features concentrations, profiles, and patterns of polychlorinated naphthalene (PCN) residues were determined in sediment, mussel, crab, plankton, and...

Purge and trap/gas chromatography/mass spectrometry method for determining smoke contamination of foods and packaging materials

Food and packaging materials from three separate fires were analyzed for volatiles by purge and trap/gas chromatography/mass spectrometry (PT/GC/MS) and compared to unexposed control samples. Concentrations of naphthalene and small alkyl-substituted (methyl, ethyl, dimethyl) naphthalene residues were consistently higher in the smoke odor containing foods than in the controls. Naphthalene and methylnaphthalene residues were used as indicators of smoke exposure in food and packaging materials. By using this method to analyze foods that had been exposed to smoke yet contained no organoleptically detectable smoke residues, it was shown that this PT/GC/MS naphthalene method is a more sensitive indicator of smoke exposure than is organoleptic evaluation.

Crystal structures of optically active naphthidine (4,4′-diamino-1,1′-binaphthyl) and 1,1′-binaphthyl

Crystals of optically active naphthidine and of binaphthyl are tetragonal, P41212 (or P43212), a = 7.945(1), 7.164(2), c = 24.264(5), 27.70(1) Å, respectively, Z = 4. The structures were solved by direct methods and refined by full-matrix least-squares techniques to respective R = 0.068 and 0.030 for 548 and 562 reflexions. The dihedral angles between the planes of the naphthalene residues are 87 and 102°, respectively. Bond lengths and angles are normal.

The crystal and molecular structure of R-(–)-1,1′-binaphthyl: the conformational isomerism and a comparison of the chiral with the racemic packing mode

The molecular and crystal structure of R-(–)-1,1′-binaphthyl has been determined from single-crystal X-ray data and refined by least-squares methods to R 0.045. The tetragonal crystal has unit-cell dimensions, a= 7.212 6(9), c= 27.510(5)A, space group P41212, and Z= 4. The molecule has a transoid conformation in the active crystal with a dihedral angle of 103° between the mean molecular planes of the two naphthalene residues. The packing modes of the molecules in the active and in the more dense (9.4%) racemic crystal are compared in connection with the spontaneous optical resolution of 1,1′-binaphthyl by crystallisation at temperatures above 76°.

Cyclic cross-conjugated hydrocarbons having an inserted p-quinonoid ring. Part 8. Quinarenes containing naphthalene residues

2″,5″-Dicyano-3″,4″-diphenyl derivatives (6) and (7) of 1-cycloheptatrienylidene-4-cyclopentadienylidene-1,4-dihydronaphthalene and 1-cycloheptatrienylidene-5-cyclopentadienylidene-1,5-dihydronaphthalene have been synthesized.

Reaction of polyion-radicals derived from polymers containing naphthalene residues with aryl and alkyl halides

The reactions of alkali metal adducts of polymers containing naphthalene groups with alkyl and aryl halides were compared with those of alkali metal naphthalene adducts. Poly-I-vinyl naphthalene, ter-poly-1-vinyl naphthalene-styrene-divinyl benzene and polyacenaphthylene were used. It was found that the alkali metal adducts of naphthalene alone and of polyacenaphthylene reacted similarly while those of naphthalene substituted on a vinyl polymer backbone reacted selectively. No reaction took place with halogen substituted on an aromatic or alicyclic ring, such as haloderivatives of benzene, naphthalene and cyclohexane. Aliphatic and benzylic organic halides reacted similarly with alkali metal naphthalene or with alkali metal adduct of poly-l-vinyl naphthalene. The results were attributed to the conformation of the alkali metal adduct of poly-l-vinyl naphthalene.

Crystal and molecular structure of 1,1′-binaphthyl

The crystal structure of 1,1′-binaphthyl has been determined by X-ray analysis. The crystals are monoclinic space group C2/c, with a= 20·98, b= 6·35, c= 10·13 A, β= 105·17°; Z= 4. The molecule exists in a cis-configuration with an angle of 68° between the planes of the two naphthalene residues, the dimensions of which are not significantly different from those of naphthalene itself. The sp2–sp2 single-bond between the two ring systems has a length of 1·475 ± 0·005 A. The final R is 0·085 for 1315 observed reflections.

Protection of Chick Embryos Against Newcastle Disease Virus by Trypan Blue and Other Compounds

Summary Of a number of related compounds tested, Trypan blue, Evans blue, Pontamine sky blue, Trypan red, Congo red and Erie garnet B protect chick embryos against Newcastle disease virus. Although the first four dyes block hemagglutination of NDV, the latter two do not, but they apparently interfere with elution of adsorbed virus. All the active compounds tested are acid, bis-azo dyes with diphenyl and naphthalene residues with two or more sulfonic acid groups. The latter two compounds have the simplest molecular structures. Trypan blue was also demonstrated to inhibit NDV in cultured mammalian cells. However, it could not be shown to have an effect on influenza virus.