Resolution of 13 polycyclic aromatic hydrocarbons by constant-wavelength synchronous spectrofluorometry.

A method capable of determining 13 PAHs (acenaphthene, anthracene, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, dibenzo[ah]anthracene, fluoranthene, fluorene, indene[1,2,3-cd]pyrene, phenanthrene and pyrene) in a mixture of 16 EPA PAHs by second derivative synchronous spectrofluorometry in the constant wavelength mode was developed. It has not been possible to determine the following PAHs in the mixture: acenaphthylene, benzo[ghi]perylene and naphthalene. The approach studied allows the sensitive, rapid and inexpensive identification and quantitation of 13 PAHs in a solution of hexane. The detection limits are <1 microg L(-1) (except for chrysene and phenanthrene).     

The development of solid-surface fluorescence characterization of polycyclic aromatic hydrocarbons for potential screening tests in environmental samples

This paper presents the characterization of polycyclic aromatic hydrocarbons (PAHs) in solid-surface fluorescence as the first step for obtaining new optical sensors for PAHs screening. The fluorescence properties of the EPA-PAHs (naphthalene, acenaphthene, acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, indeno [1,2,3-cd]pyrene, benzo[g,h,i]perylene and dibenzo[a,h]anthracene) on five types of solid-surfaces were evaluated. The experimental variables (pH and percentage of organic solvent in samples) were studied, obtaining different possibilities for making individual sensors for some of these PAHs and the best conditions for developing sensors for PAH screening were also studied.     

Interpretative optimization and artificial neural network modeling of the gas chromatographic separation of polycyclic aromatic hydrocarbons

An interpretative strategy (factorial design experimentation+total resolution analysis+chromatogram simulation) was employed to optimize the separation of 16 polycyclic aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-c,d)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene) in temperature-programmed gas chromatography (GC). Also, the retention behavior of PAHs in the same GC system was studied by a feed-forward artificial neural network (ANN). GC separation was investigated as a function of one (linear temperature ramp) or two (linear temperature ramp+the final hold temperature) variables. The applied interpretative approach resulted in rather good agreement between the measured and the predicted retention times for PAHs in both one and two variable modeling. The ANN model, strongly affected by the number of input experiments, was shown to be less effective for one variable used, but quite successful when two input variables were used. All PAHs, including difficult to separate peak pairs (benzo(k)fluoranthene/benzo(b)fluoranthene and indeno(1,2,3-c,d)pyrene/dibenzo(a,h)anthracene), were separated in a standard (5% phenyl-95% dimethylpolysiloxane) capillary column at an optimum temperature ramp of 8.0 degrees C/min and final hold temperature in the range of 260-320 degrees C.     

Gas chromatographic-mass spectrometric determination of polycyclic aromatic hydrocarbons formed during the pyrolysis of phenylalanine

The formation of polycyclic aromatic hydrocarbons (PAHs) during pyrolysis process of phenylalanine had been studied. Ten PAHs, including fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[k]fluoranthene, benzo[e]pyrene, and benzo[a]pyrene were analyzed by gas chromatography-mass spectrometry using selective ion monitoring mode. This technique offers the capability to analyze trace amounts of PAHs in phenylalanine pyrolyzates. The pyrolysis was carried out in a micro-furnace with quartz furnace liner. The injection was conducted with glass pelletizer syringe to avoid metal contamination. Qualitative results were obtained at 900 degrees C and quantitative analysis of 10 PAHs was done for 700 and 900 degrees C.     

Solid-surface phosphorescence characterization of polycyclic aromatic hydrocarbons and selective determination of benzo(a)pyrene in water samples

This paper presents the phosphorescence characterization of polycyclic aromatic hydrocarbons (PAHs) on solid-surface for obtaining new flow-through phosphorescence optosensors for PAHs-based on-line, immobilized onto a non-ionic resin solid support coupled to a continuous flow system and the applications for the selective determination of benzo(a)pyrene (BaP). The phosphorescent characterization of 15 PAHs, described as major pollutants by the Environmental Protection Agency (EPA) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene and dibenzo(a,h)anthracene) has been carried out. The experimental variables (heavy atom, deoxygenation and organic solvent in samples) for obtaining different possibilities for developing mono and multi-parameter PAH sensors and the conditions for PAH screening have been carefully studied and the experimental conditions to determination of BaP in presence of other PAHs in water samples have been optimized.     

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.     

Polycyclic aromatic hydrocarbons (PAHs) in edible oils by gas chromatography coupled with mass spectroscopy

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in nine edible oils of three categories of oil samples, such as soy bean oil, mustard oil and coconut oil, has been studied to determine the contamination degree of this type of oil samples. Eight major carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, anthracene, phenanthrene, fluorene, pyrene, crysene, benzo(a)pyrene and benzo(a)anthracene, were identified and quantified in the extract of edible oils collected from Bangladeshi Markets by gas chromatography and mass spectroscopy. All of the carcinogenic PAHs are not present in the edible oils. A few of the carcinogenic PAHs are present in the oils but it is within the permissible limit. The results for the recoveries of naphthalene, fluorene, phenanthrene, anthracene, pyrene, crysene, benzo(a)anthracene and benzo(a)pyrene were in the range of 56–84%. The limit of detection (LOD) of the GC–MS method, established at signals three times that of the noise for naphthalene, fluorene, phenanthrene, anthracene, pyrene, crysene, benzo(a)anthracene and benzo(a)pyrene, was 2.0–2.5 ng, respectively.     

Polycyclic aromatic hydrocarbon-isomer fragmentation pathways: case study for pyrene and fluoranthene molecules and clusters

We report on measurements of the ionization and fragmentation of polycyclic aromatic hydrocarbon (PAH) targets in Xe(20+)?+ C(16)H(10) and Xe(20+)?+ [C(16)H(10)](k) collisions and compare results for the two C(16)H(10) isomers: pyrene and fluoranthene. For both types of targets, i.e., for single PAH molecules isolated in vacuum or for isomerically pure clusters of one of the molecules, the resulting fragment spectra are surprisingly similar. However, we do observe weak but significant isomer effects. Although these are manifested in very different ways for the monomer and cluster targets, they both have at their roots small differences (<2.5 eV) between the total binding energies of neutral, and singly and multiply charged pyrene and fluoranthene monomers. The results will be discussed in view of the density functional theory calculations of ionization and dissociation energies for fluoranthene and pyrene. A simple classical over-the-barrier model is used to estimate cross sections for single- and multiple-electron transfer between PAHs and ions. Calculated single and multiple ionization energies, and the corresponding model PAH ionization cross sections, are given.     

Multivariate calibration applied to synchronous fluorescence spectrometry. Simultaneous determination of polycyclic aromatic hydrocarbons in water samples

Synchronous fluorescence spectra of mixtures containing ten polycyclic aromatic hydrocarbons (anthracene, benz[a]anthracene, benzo[a]pyrene, chrysene, fluoranthene, fluorene, naphthalene, perylene, phenanthrene and pyrene) have been used for the determination of these compounds by Partial Least Squares Regression (PLSR), using both PLS-1 and PLS-2. Different procedures have been used for the pretreatment of the data in order to obtain better models, and the size of the calibration matrix has also been studied. The best models have been used for the determination of the above mentioned PAHs in spiked natural water samples at concentration levels between 4 and 20 ng ml⁻¹. Recoveries ranged from 80 to 120% in most cases, although fluorene gave significantly lower results.     

Dissociation and multiple ionization energies for five polycyclic aromatic hydrocarbon molecules

We have performed density functional theory calculations for a range of neutral, singly, and multiply charged polycyclic aromatic hydrocarbons (PAHs), and their fragmentation products for H-, H(+)-, C(2)H(2)-, and C(2)H(2)(+)-emissions. The adiabatic and vertical ionization energies follow linear dependencies as functions of charge state for all five intact PAHs (naphthalene, biphenylene, anthracene, pyrene, and coronene). First estimates of the total ionization and fragmentation cross sections in ion-PAH collisions display markedly different size dependencies for pericondensed and catacondensed PAH species, reflecting differences in their first ionization energies. The dissociation energies show that the PAH(q+)-molecules are thermodynamically stable for q ≤?2 (naphthalene, biphenylene, and anthracene), q?≤?3 (pyrene), and q?≤?4 (coronene). PAHs in charge states above these limits may also survive experimental time scales due to the presence of reaction barriers as deduced from explorations of the potential energy surface regions for H(+)-emissions from all five PAHs and for C(2)H(2)(+)-emission from naphthalene--the smallest PAH.     

Theoretical study on oligoacenes and polycyclic aromatic hydrocarbons using the restricted active space self-consistent field method

This is the first study, to my knowledge, to report the optimized geometries and vibrational frequency analysis for oligoacenes (naphthalene, anthracene, naphtacene, and pentacene) and polycyclic aromatic hydrocarbons (PAHs; perylene, phenanthrene, and picene) by using the restricted active space self-consistent field (RASSCF) method. For naphthalene, both the complete active space self-consistent field (CASSCF) and RASSCF calculations were performed. As a result, it was confirmed that the RASSCF, with its small computational costs, is appropriate for oligoacenes and PAHs. It should be noted that, for anthracene and perylene, the optimized geometries under D(2h) symmetry were not the minimum energy points, whereas the optimized geometries under C(s) symmetry were the minimum energy points. For naphthalene, anthracene, naphtacene, pentacene, and phenanthrene, the calculated bond lengths and infrared absorption spectra by the RASSCF were in good agreement with the experimental values.     

超高效合相色谱快速分析塑料制品中的18种多环芳烃

建立了一种超高效合相色谱-二极管阵列检测器快速分析塑料制品中萘、苊烯、苊、芴、菲、蒽、荧蒽、芘、苯并(a)蒽、(屈艹) 、苯并(b)荧蒽、苯并(k)荧蒽、苯并(j)荧蒽、苯并(e)芘、苯并(a)芘、茚并(1,2,3-cd)芘、二苯并(a,h)蒽、苯并(g,h,i)苝(二萘嵌苯)的方法。以甲苯为溶剂,超声萃取实际塑料制品中的多环芳烃,经超高效合相色谱分析。采用Daicel IB-3手性色谱柱,以CO₂为流动相,甲醇/乙腈(25:75, v/v)为流动相助溶剂,在柱温为40 ℃,背压为15.17 MPa的条件下,18种多环芳烃在8.5 min之内实现基线分离。18种多环芳烃的线性范围为0.05~50 mg/L(r≥0.9995),定量限(S/N> 10)为0.05 mg/L。加标回收率为78.3%~117.6%,相对标准偏差(RSD, n=5)小于5%。该方法具有分析速度快、分离效率高、节约有机溶剂的优点。     

The application of an in vitro gastrointestinal extraction to assess the oral bioaccessibility of polycyclic aromatic hydrocarbons in soils from a former industrial site

The total and bioaccessible concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in soil from a former industrial site was investigated. Typical total concentrations across the sampling sites ranged from 1.5 mg kg⁻¹ for acenaphthylene up to 243 mg kg⁻¹ for fluoranthene. The oral bioaccessibility of PAHs in soil was assessed using an in vitro gastrointestinal extraction (Fed Organic Estimation human Simulation Test, FOREhST method). The oral bioaccessibility data indicated that fluorene, phenanthrene, chrysene, indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene had the highest % bioaccessible fraction (based on their upper 75th percentile values being >60%) while the other PAHs had lower % bioaccessible fractions (means ranging between 35 and 59%). Significantly lower bioaccessibilities were determined for naphthalene. With respect to method validation and inter-laboratory comparison, the total and bioaccessible concentrations of benzo(a)anthracene, benzo(b)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene and dibenzo(a,h)anthracene was compared to published data derived using the same samples. The total PAH concentrations at the site were compared with generic assessment criteria (GAC) using the residential land use scenario (with plant uptake at 6% soil organic matter). Concentrations of 7 of the PAHs investigated within the soils could lead to an unacceptable risk to human health at this site.     

Structural analysis of leukotriene C<Subscript>4</Subscript> isomers using collisional activation and 157 nm photodissociation

The fragmentation of 5-hydroxy-6-glutathionyl-7,9,11,14-eicosatetraenoic acid [leukotriene C4 or LTC4 (5, 6)] and its isomeric counterpart LTC4 (14, 15) were studied by low and high-energy collisional induced dissociation (CID) and 157 nm photofragmentation. For singly charged protonated LTC4 precursors, photodissociation significantly enhances the signal intensities of informative fragment ions that are very important to distinguish the two LTC4 isomers and generates a few additional fragment ions that are not usually observed in CID experiments. The ion trap enables MSn experiments on the fragment ions generated by photodissociation. Photofragmentation is found to be suitable for the structural identification and isomeric differentiation of cysteinyl leukotrienes and is more informative than low or high-energy CID. We describe for the first time the structural characterization of the LTC4 (14, 15) isomer by mass spectrometry using CID and 157 nm light activation methods.     

Determination of polycyclic aromatic hydrocarbons (PAHs) and total fats in human milk

A sensitive and reliable analytical method was developed for the simultaneous extraction of PAHs and total fats and their determination in the human milk. The method involved a liquid-liquid extraction of PAHs and fats, followed by the gravimetric determination of the latter. PAHs were separated from lipids by size exclusion chromatography eluting with methylene chloride and analysed by gaschromatography coupled with mass spectrometry (GC/MS). The recovery of analytes was in the range of 42-101% and agreed well with their boiling temperatures (R2=0.779). Precision of the method was found between 7.6 and 19%. Quantification and detection limits for individual PAHs ranged from 0.011 to 0.032 and from 0.006 to 0.022 microg/Kg milk (wet weight), respectively. Quantification limit for the total fat determination was 0.26 g/Kg milk (wet weight). This procedure, applied to milk samples of ten healthy, non-smoking, Italian primiparae, living in rural or low-traffic zones, allowed for the identification and quantitative determination of naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene in the mean concentration range 0.114-6.95 microg/Kg milk (wet weight). The most volatile compounds, which were not investigated elsewhere, were found at much higher concentrations than those observed for the others. No relation was found between PAH and total fat concentrations.     

致癌性多环芳烃萘、蒽、芘的分析方法比较

利用薄层色谱（TLC）、紫外光谱（UV）、反相高效液相色谱（RPHPLC）对多环芳烃（PAHs）萘、蒽、芘的分析方法进行了研究。TLC中使用环己烷：氯仿（5：4,V／V）作为展开剂时,三者的R,值分别为0．78、0．65和0．72;用UV法在溶液中测定了三者的最大吸收波长分别为303、380、338nm;当流动相为甲醇：水（9：1,V／V）时三者在RP—HPLC中的保留时间为4．179、5．190、6．178min,5次重复RSD分别为1．1％、1．8％、0．91％,并用于实际水样中萘、蒽、芘的分析。     

New approach for screening polycyclic aromatic hydrocarbons in water samples

For the first time, solid-phase extraction (SPE) has been combined to room-temperature phosphorimetry (RTP) to determine the 16 polycylic aromatic hydrocarbons related as major pollutants by the US Environmental Protection Agency (EPA). These include naphthalene, anthracene, acenaphthylene, acenaphthene, fluorene, fluoranthene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, pyrene, chrysene, phenanthrene, benzo(g,h,i)perylene and dibenzo(a,h)anthracene. The pre-concentration factor obtained by SPE, combined with the sensitivity of RTP, resulted in calibration curves with linear dynamic ranges at the parts-per-billion level (ng ml(-1)). The limits of detection were estimated at the parts-per-trillion level (pg ml(-1)). Several pollutants usually encountered in water samples were tested for interference. These included polychlorinated biphenyls, pesticides, and volatile organic compounds. As a result of the appropriate combination of excitation wavelength (330 nm) and phosphorescence enhancers (0.1 M TlNO(3) and 0.05 M sodium dodecyl sulfate, SDS), no interference was observed. The results demonstrate the potential of SPE-RTP for screening polycyclic aromatic hydrocarbons (PAHs) in environmental waters.     

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.     

Quantitative determination of trace concentration of organics in water by solvent extraction and fused silica capillary gas chromatography: aliphatic and polynuclear hydrocarbons

Solvent extraction procedures with six different solvents on aqueous model systems of aliphatic (C12-C22) and polynuclear aromatic hydrocarbons (PAHs: Naphthalene, acenaphtene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene) were studied for the analysis in the trace concentration range (20-50 ng ml-1) by fused silica capillary gas chromatography. Recovery efficiencies, reproducibilities and detection limits for each analyte and procedure are reported. The effect of the PAHs on the extracting rate of the aliphatic hydrocarbons at the trace concentration range is discussed.