Multivariate Fluorimetric Determination of Mixture of Pyrene,Perylene and Triphenylene in Water Sample

ABSTRACT

Micellization is described as a successful media for simultaneous fluorimetric determination of perylene, pyrene and triphenylene in water samples by reducing interference between them. A multivariate method based on synchronous fluorescence scan to estimate perylene, pyrene and triphenylene in their mixture solution has been proposed. The method does not require solving of large amounts of data obtained from the whole spectrum of the samples, thus making the analysis simple and fast. The method gives the best result for perylene and satisfactory results for pyrene and triphenylene. Analysis of water samples of two different origins spiked with known amount of perylene, pyrene and triphenylene also gives satisfactory result. Presence of fluoranthene up to 1 μM does not interfere in the analysis.     

Error propagation as a factor in selection of measurement intervals for the determination of polycyclic aromatic hydrocarbons by second-derivative spectrofluorimetry

The most suitable wavelength intervals were selected for the determination of 4 polycyclic aromatic hydrocarbons (PAHs; benzo[g,h,i]perylene, dibenzo[a,h]anthracene, pyrene, and triphenylene) in very complex mixtures of 11 PAHs: anthracene, benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene, phenanthrene, pyrene, and triphenylene. The multiple linear regression algorithm was applied to measurements made in several wavelength intervals previously selected on the basis of sensitivity and minimum number of interfering compounds. Of the different models obtained, those displaying minimum error propagation in the analytical result were selected. By applying the models proposed in this study, we precisely and accurately determined benzo[g,h,i]perylene, dibenz[a,h]anthracene, pyrene, and triphenylene in complex mixtures--a feat that could not be achieved by the use of constant-wavelength spectrofluorimetry in combination with second-derivative techniques.     

A novel salicylate-selective electrode based on a Sn(IV) complex of salicylal-imino acid Schiff base

A novel poly(vinyl chloride) membrane electrode with high selectivity toward salicylate (Sal^–), based on the use of the salicylal-imino acid Schiff base dibenyl complex of Sn(IV) [Sn(IV)-SIADBen] as ionophore is described. The influence of lipophilic charged additives on the performance of the electrode was studied. The results suggested that Sn(IV)-SIADBen according to a positively-charged carrier mechanism. The influence of several other variables was investigated in order to optimize the potentiometric response and selectivity of the electrode. The electrode based on Sn(IV)-SIADBen, with 30.44 wt% PVC, 64.55 wt% plasticizer [dioctyl phthalate (DOP)], 3.81 wt% ionophore, and 1.2 wt% anionic additive exhibited a linear response for the Sal^– ion over the concentration range 1.0×10^–1 to 2.5×10^–6 mol l^–1, and displayed an anti-Hofmeister selectivity sequence as follows: salicylate perchlorate > thiocyanate > benzoate > iodide > nitrate > chloride > nitrite acetate > citrate > sulfate. UV-Visible absorption spectra were used to examine the specific interaction of salicylate with the ionophore. The electrode was applied to clinical medical analysis, and the results obtained were consistent with those obtained by conventional methods.     

Feasibility of low-voltage cathodic electroluminescence at oxide-covered aluminum electrodes for trace metal determinations in aqueous solutions

Metal-catalyzed electroluminescence is generated at an oxide-covered aluminum electrode during the reduction of oxygen, potassium peroxodisulfate, and especially hydrogen peroxide in aqueous solutions. The feasibility of this electroluminescence for the determination of copper (5 × 10^?9 M) and thallium (> 10^?10 M) is demonstrated.     

Admicelle-enhanced synchronous fluorescence spectrometry for the selective determination of polycyclic aromatic hydrocarbons in water

A simple and rapid method for the highly sensitive determination of polycyclic aromatic hydrocarbons (PAHs) in water was developed. Benzo[a]pyrene, benzo[k]fluoranthene, perylene, and pyrene in water were concentrated into sodium dodecyl sulfate (SDS)-alumina admicelles. The collection was performed by adding SDS and alumina particles into the sample solution at pH 2. After gentle mixing, the resulting suspension was passed through a membrane filter to collect the SDS admicelles containing highly concentrated PAHs. The filter was placed on a slide glass and then covered admicellar layer with a fused silica glass plate before setting in a fluorescence spectrometer. Benzo[a]pyrene, benzo[k]fluoranthene, perylene, and pyrene were selectively determined by the synchronous fluorescence scan (SFS) analysis with keeping wavelength intervals between excitation and emission to 98, 35, 29, and 45 nm, respectively. Because of the minimum spectral overlapping, 1-40 ng l⁻¹ of benzo[a]pyrene, benzo[k]fluoranthene, and perylene as well as 10-150 ng l⁻¹ of pyrene were selectively determined with eliminating the interferences of other 12 PAHs. The detection limits were 0.3 ng l⁻¹ for benzo[a]pyrene, benzo[k]fluoranthene, and perylene, and 1 ng l⁻¹ for pyrene. They were 2-3 orders of magnitude lower than the detection limits in normal aqueous micellar solutions. The application to water analysis was studied.     

Infrared Cavity Ringdown Spectroscopy of Jet‐Cooled Polycyclic Aromatic Hydrocarbons

Infrared absorption spectra of the CH stretching region were observed for naphthalene, anthracene, phenanthrene, pyrene, and perylene using a heated, supersonic, slit‐jet source and cavity ringdown spectroscopy. Band positions and intensities recorded with 0.2‐cm^?1 resolution were compared with previous gas‐phase and argon matrix isolation experiments, as well as theoretical calculations. The largest matrix shift in the absorption maximum (‐7.4 cm^?1) was observed for anthracene, with all others shifted by 3.0 cm^?1 or less. Spectral features in the supersonic jet spectrum were generally narrower than those observed in the Ar matrix, with the largest matrix broadening found for the perylene (80 % increase). Low number densities observed for the larger polycyclic aromatic hydrocarbons (PAHs) suggest that the lower vapor pressure of PAHs with catacondensed four‐membered rings and with five‐membered rings other than perylene will not be detectable using our current configuration.     

Penetration of mercury-adsorbed phospholipid monolayers by polynuclear aromatic hydrocarbons

The penetration of phospholipid monolayers (dioleoyl lecithin) adsorbed on mercury by polynuclear aromatic hydrocarbons (PAH) is described. The PAH studied were anthracene, phenanthrene, pyrene, benzo[a]anthracene, fluoranthene and perylene. The penetration is monitored by measuring the differential capacitance of the monolayer; the uptake of PAH causes a potential shift (up to ?0.25 V) in the cathodic capacitance peaks. This occurs without displacement of the lipid from the mercury. The differential capacitance is measured by out-of-phase (90°) a.c. voltammetry and rapid cyclic voltammetry. The PAH permeate the mercury-adsorbed lipid layers from dilute aqueous solution; the order of affinity is benzo[a]anthracene > fluoranthrene = pyrene > anthracene = phenanthrene. The rates of penetration vary for the different compounds and depend on their water solubility.     

Synthesis of di-, tri-, tetra- and pentacyclic arene complexes of ruthenium(II):[Ru(η-polycyclic arene)-(1-5-η-cyclooctadienyl)]PF6 and their reactions with NaBH4

The phenanthrene complex of ruthenium(II), [Ru(η⁶-phenanthrene)(1,5-η⁵-cyclooctadienyl)]PF₆ (2c), is prepared by the reaction of Ru(η⁴-1,5-COD)(η⁶-1,3,5-COT) (1) with phenanthrene and HPF₆ in 65% yield. Similar treatments with di- tri-, tetra- and pentacyclic arenes give corresponding polycyclic arene complexes, [Ru(η⁶-polycyclic arene)(1-5-η⁵-cyclooctadienyl)]PF₆ [polycyclic arene = naphthalene (2b), anthracene (2d), triphenylene (2e), pyrene (2f) and perylene (2g)] in 46-90% yields. The molecular structure of the perylene complex 2g is characterized by X-ray crystallography. Reaction of 2c with NaBH₄ gives a mixture of the 1,5- and 1,4-COD complexes of ruthenium(0), Ru(η⁶-phenanthrene)(η⁴-1,5-COD) (3c) and Ru(η⁶-phenanthrene)(η⁴-1,4-COD) (4c) in 76% in 1:8 molar ratio. The arene exchange reactions among cationic complexes [Ru(η⁶-arene)(1-5-η⁵-cyclooctadienyl)]PF₆ (2) showed the coordination ability of arenes in the following order: benzene ∼ triphenylene > phenanthrene > naphthalene > perylene ∼ pyrene > anthracene, suggesting the benzo fused rings, particularly those of acenes, decreasing thermal stability of the arene complex.     

Supersonic jet fluorescence spectrometry of perylene and benzo[a]pyrene

A supersonic jet instrument for fluorescence spectrometry is described. It consists of a high-temperature free expansion nozzle for continuous sample introduction and a vacuum chamber equipped with a high-speed pumping system. Rotationally cooled spectra obtained with the supersonic jet are compared with gas-phase spectra measured at high temperature for perylene and benzo[a]pyrene molecules. Each component of the unresolved band structure in the high-temperature spectra was found to be composed of a rotational congestion of several vibrational bands. For a 1:1 mixture of perylene and benzo[a]pyrene, selective detection is possible by using supersonic jet spectrometry. The detection limit for perylene is 100 ng. The advantage of this technique over other low-temperature spectrometric methods based on Shpol'skii and matrix isolation effects are discussed.     

Study on the inclusion interaction of ethyl violet with cyclodextrins by MWNTs/Nafion modified glassy carbon electrode

The interactions of ethyl violet (EV) with cyclodextrins (CDs) were investigated by Multi-wall carbon nanotubes/Nafion composite film modified glassy carbon electrode (MWNTs/Nafion/GCE). It was found that the MWNTs/Nafion composite film can effectively catalyze the electrode reaction of EV. The variation of the electrochemical behavior of EV upon the addition of CDs indicated the formation of the inclusion complexes of EV with β-CD, heptakis (2,3,6-tri-O-methyl)-β-CD (TM-β-CD), heptakis (2,6-di-O-methyl)-β-CD (DM-β-CD), hydroxypropyl-β-CD (HP-β-CD), and carboxymethyl-β-CD (CM-β-CD). The stoichiometry ratios of EV and the above five CDs were found to be 1:1. The inclusion ability obeyed the order: CM-β-CD > HP-β-CD > TM-β-CD > DM-β-CD > β-CD. The results showed that the modified β-CDs exhibited stronger binding ability than native β-CD, especially the charged CM-β-CD, which implied that the inclusion capacity depends on not only size matching and hydrophobicity but also electrostatic interaction. ¹HNMR spectra and molecule mechanics calculations suggested that EV was included into the cavity of β-CD from the wider side.     

A distributed multipole analysis of the charge densities of some aromatic hydrocarbons

SCF wavefunctions have been calculated for benzene, naphthalene, anthracene, phenanthrene, pyrene, triphenylene, perylene and coronene using a 3-21G basis set, and for benzene and naphthalene with a double-zeta basis set. A direct SCF method was used for the calculations on the three largest molecules. The distributed multipole analyses of these wavefunctions are used to comment on empirical models for the electrostatic interactions of these molecules.     

Investigation of the two-photon absorption cross-section in perylene tetracarboxylic derivatives: nonlinear spectra and molecular structure

We investigated the 2PA absorption spectrum of a family of perylene tetracarboxylic derivatives (PTCDs): bis(benzimidazo)perylene (AzoPTCD), bis(benzimidazo)thioperylene (Monothio BZP), n-pentylimidobenzimidazoperylene (PazoPTCD), and bis(n-butylimido)perylene (BuPTCD). These compounds present extremely high two-photon absorption, which makes them attractive for applications in photonics devices. The two-photon absorption cross-section spectra of perylene derivatives obtained via Z-scan technique were fitted by means of a sum-over-states (SOS) model, which described with accuracy the different regions of the 2PA cross-section spectra. Frontier molecular orbital calculations show that all molecules present similar features, indicating that nonlinear optical properties in PTCDs are mainly determined by the central portion of the molecule, with minimal effect from the lateral side groups. In general, our results pointed out that the differences in the 2PA cross-sections among the compounds are mainly due to the nonlinearity resonance enhancement.     

Luminescence analysis of complex organic materials based on resolved line spectra produced by selective laser excitation

Selective methods of obtaining the resolved line spectra of the solutions of complex molecules, along with the peculiarities of these spectra, are considered. At sufficiently low temperatures (4.2 K), broad-band absorption and luminescence spectra of the solutions of organic compounds are often broadened, mainly inhomogeneously. Excitation of the luminescence by tunable lasers can eliminate this broadening. The spectra obtained consist of dozens of narrow (Δv ≈ 1 cm^-1) vibrational lines. Some examples of selective excitation for the spectrofluorimetric analysis of complex organic materials are given: identification (at the 10^-11 g ml^-1 level) and determination of individual polynuclear hydrocarbons in certain materials without preliminary separation is demonstrated by the determination of benzopyrene and perylene in gasoline and the detection of perylene in a solid paraffin.     

Porphyrin-perylene bisimide dyads and triads: synthesis and optical and coordination properties

[structure: see text] Novel porphyrin perylene dyad and triad dyes have been prepared by the coupling of aminophenyltrisphenylporphyrin and tetraphenoxy-substituted perylenetetracarboxylic acid bisanhydrides in a one-step synthesis. Fluorescence spectra of these compounds reveal features that are attributable to emission of perylene bisimides as well as porphyrin excited states. The self-assembly behavior of zinc-metalated compounds with 4,4'-bipyridine and diazabenzoperylene has been investigated by (1)H NMR spectroscopy in CDCl(3), showing that oligomeric zigzag assemblies are formed.     

Validation of a method for extraction of polycyclic aromatic hydrocarbons from sewage sludge and analysis by GC-MS

In the present study, the solid–liquid extraction with low temperature purification was validated for the determination of 16 polycyclic aromatic hydrocarbons from sewage sludge by gas chromatography-mass spectrometry. Recoveries ranged 70–114% for naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene and chrysene, while the compounds benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene showed recoveries of between 40 and 70%. The relative standard deviation was less than 13% for all of the compounds. Negative matrix effect was observed on the 10 compounds with less retention time in the chromatographic analysis and positive matrix effect noticed on the others. The limits of quantification were from 2 to 20 μg kg^?1, about 30 times less than the maximum residue limit allowed in sludge by the European Union. The validated method produced quantification of 11 PAHs in one sludge sample at concentrations ranging 20–2000 μg kg^?1.     

High-resolution electron spectroscopy, preferential metal-binding sites, and thermochemistry of lithium complexes of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons are model systems for studying the mechanisms of lithium storage in carbonaceous materials. In this work, Li complexes of naphthalene, pyrene, perylene, and coronene were synthesized in a supersonic metal-cluster beam source and studied by zero-electron-kinetic-energy (ZEKE) electron spectroscopy and density functional theory calculations. The adiabatic ionization energies of the neutral complexes and frequencies of up to nine vibrational modes in the singly charged cations were determined from the ZEKE spectra. The metal-ligand bond energies of the neutral complexes were obtained from a thermodynamic cycle. Preferred Li∕Li(+) binding sites with the aromatic molecules were determined by comparing the measured spectra with theoretical calculations. Li and Li(+) prefer the ring-over binding to the benzene ring with a higher π-electron content and aromaticity. Although the ionization energies of the Li complexes show no clear correlation with the size of the aromatic molecules, the metal-ligand bond energies increase with the extension of the π-electron network up to perylene, then decrease from perylene to coronene. The trends in the ionization and metal-ligand bond dissociation energies of the complexes are discussed in terms of the orbital energies, local quadrupole moments, and polarizabilities of the free ligands and the charge transfer between the metal atom and aromatic molecules.     

Direct determination of selected polynuclear aromatic hydrocarbons in a coal liquefaction product by synchronous luminescence techniques

Synchronous fluorescence and the room-temperature phosphorescence methods were used to determine selected polynuclar aromatic hydrocarbons in a coal liquid (solvent-refined coal) product without a preseparation step. The procedure identified and quantified ten polynuclear aromatic compounds including anthracene, 2,3-benzofluorene, benzo[a]pyrene, benzo[e]pyrene, carbazole, dibenzothiophene, fluoranthene, fluorene, perylene and pyrene. Standard deviations for repeated determinations ranged from 10–30% for concentrations in the range of 0.1–6 mg g^-1. The data obtained by these methods agree with results by other methods within the estimated experimental uncertainty.     

Use of coacervates for the on-site extraction/preservation of polycyclic aromatic hydrocarbons and benzalkonium surfactants

The suitability of coacervates for the preservation of organic pollutants after their extraction from water samples was investigated for the first time. Acid-induced sodium dodecanesulfonic acid (SDSA) micelle-based coacervates were selected for this purpose. Their capacity to preserve benzalkonium homologue (C₁₂, C₁₄ and C₁₆) surfactants (BASs) and different polycyclic aromatic hydrocarbons (PAHs) [benzo(a)pyrene (BaP), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(ghi)perylene (BghiP), benzo(a)anthracene (BaA) and indene(1,2,3-c-d)pyrene (IP)] was investigated. BASs and PAHs were efficiently extracted by the coacervate by formation of mixed aggregates and hydrophobic interactions, respectively. Their stability into the coacervate was investigated under three temperature conditions (room temperature, 4 °C and −20 °C) and two hydrochloric acid concentrations (3.75 M and 4.2 M), which was used to induce coacervation. No losses were observed during at least 3 months at the different experimental conditions tested. The increase of the temperature up to 35 °C for a month did not affect the stability of the target compounds. No influence of the water matrix (distilled, river or wastewater) on the stabilization of BASs and PAHs was observed. The high-stabilizing capacity of the coacervate for the target compounds and its low volume make easy the transport and storage of analytes.     

Highly Thiocyanate‐Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative

A novel anion‐selective PVC membrane electrode based on bis‐[(3‐ferrocenyl)‐(2‐crotonic acid)] copper(II) complex [Cu(II)‐BFCA] as neutral carrier is described, which demonstrates excellent potentiometric response characteristics toward thiocyanate ion and anti‐Hofmeister selectivity sequence in following order: SCN^?>I^?>ClO >Sal^?>Br^?>NO >Cl^?≈NO >SO >SO . The electrode shows a near‐Nernstian response for thiocyanate ion in a wide range of 9.0×10^?7–1.0×10^?1 M with a detection limit 6.8×10^?7 M and a slope of ?59.1 mV/decade in pH 5.0 of phosphate buffer solution at 20 °C. The influences of lipophilic cationic and anionic additives on the response properties of the electrode were investigated. High sensitivity and wide linear dynamic range were observed for the electrode in the presence of hexadecyltrimethylammoniumborate (HTAB) as a lipophilic cationic additive. The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.     

Jet spectroscopy of pyrene complexes: Unusual complexation shifts in the S0 → S1 spectrum

The fluorescence excitation spectra of pyrene complexes with n-alkanes are reported for the S₀ → S₁ and S₀ → S₂ transitions. The S₂ spectral shifts are predictable from theory, and by comparison with other molecules, such as perylene. On the other hand, the S₁ Resonances of pyrene complexes show unusually small displacements from those of the parent species. The spectra of the butane, pentane and hexane complexes actually exhibit net blue shifts. This behaviour provides good evidence for a repulsive interaction in the S₁ state, which is not observed in S₂. Moreover, because the butadiene and benzene complexes give predictable red shifts ⩾ 100 cm⁻¹, and these are found to have plane-parallel geometries, the blue shift correlates with a host carbon—guest hydrogen interaction in the repulsive regime. We also report that the ethylene complex of pyrene exhibits a net blue shift on the S₀ → S₁ transition, and a red shift on S₀ → S₂ only 75% of the predicted value, based on measurements with perylene complexes. This behaviour strongly indicates that ethylene-pyrene has a T-shaped configuration, as predicted by potential energy calculations.