Determination of Polycyclic Aromatic Compounds in Asphalt and in Corresponding Leachate Water

The environmental impact of polycyclic aromatic compounds (PACs) in asphalt (bitumen) materials is related to their availability for environmental transport and biouptake, rather than their total concentrations. This study examines six Strategic Highway Research Program (SHRP) paving asphalts and four commercial roofing asphalts. Three cleanup procedures for the neat asphalt samples are evaluated. This study reports on analyses for 29 PACs, including the EPA 16 priority pollutant PAHs and additional Persistent Bioaccumulative Toxins. These require reporting by the U.S. EPA under the Emergency Planning and Community Right-to-Know Act (EPCRA) section 313. The analytical protocol for analysis of the higher molecular weight PACs by GC/MS is reported, with inclusion of GC/MS/MS verification of some of the detectable compounds. Additionally, each asphalt was taken through a toxicity characteristic leaching procedure following U.S. EPA method SW846-1311. Results of the paving and roofing asphalts and their corresponding leachate waters are presented in this study.     

Comparison of Sample Preparation and Analysis Using Solid-Phase Extraction and Solid-Phase Microextraction to Determine Monohydroxy PAH in Urine by GC/HRMS

Sample preparation techniques using solid-phase extraction (SPE) and solid-phase microextraction (SPME) are compared for the analysis of monohydroxy polycyclic aromatic hydrocarbons (OHPAH) in human urine. Urine samples spiked with five carbon-13 labeled internal standards are first enzymatically hydrolyzed. Sixteen OHPAH from eight parent compounds (naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, benzo[ c ]phenanthrene, and benz[ a ]anthracene) are then extracted along with the internal standards by these two different techniques. The analytes are derivatized by a silylating reagent before final analysis. Final separation and detection are performed by temperature-programmed capillary gas chromatography (GC) and high-resolution mass spectrometry (HRMS). The two extraction techniques are compared for sample preparation time, cost, throughput, reinjection possibility, frequency of outliers, matrix interference, signal linearity, and method detection limit. SPE demonstrates major advantages over SPME for most of these aspects.     

Analysis of Polycyclic Aromatic Compounds in Soil Samples Using Laser-Induced Phosphorimetry

Abstract

The analysis and spectral characteristics of several polycyclic aromatic hydrocarbons (PAHs) have been investigated by Laser-Induced Solid-Surface Room Temperature Phosphorimetry (LI-SSRTP). These PAHs included phenanthrene, chrysene, 1,2 benzofluorene, 2,3 benzofluorene, pyrene, coronene, 1,2,3,4 dibenzanthracene, benzo(a)pyrene, benzo(e)pyrene, and benzo(g, h, i)perylene. A nitrogen laser was employed as the excitation source at 337 nm. Filter paper treated with UV irradiation for background reduction was used as the solid substrate. Thallium(I)acetate was employed as a phosphorescence enhancer. Absolute limits of detection in the picogram level were obtained for all the PAHs, improving SSRTP levels of detection by three orders of magnitude. Finally, the proposed method was tested with a PAH contaminated soil sample. Detection of several PAHs at the nanogram level was easily performed, showing the potential of LI-SSRTP to the analysis of samples of environmental concern.     

Biomonitoring of Atmospheric PAHs by Evergreen Plants: Correlations and Applicability

This article deals with looking for the best passive samplers among eleven plants diffused in the Mediterranean basin for the determination of polycyclic aromatic hydrocarbons in the atmosphere in substitution to the particulate matter sampling. The most recent research about biological passive samplers showed a quali-quantitative difference in pollutant sampling by different plants. Evergreen trees with long-lived leaves were selected in the urban area of Catania (Italy) and both samples (leaves and particulate matter) were extracted and purified by a two stage method before the analysis was performed by a GC/MS. Leaves and particulate matter were sampled in three different seasons (winter, spring and summer). PAHs concentrations found in the particulate matter and leaves were correlated. Some plants ( Olea europaea and Quercus ilex ) showed high values (r 2 > 0.85) of linear correlation coefficient in all seasons and are characterized by profiles similar to that of the particulate matter. Further, it has been observed that during the warmer seasons the total quantity of PAH adsorbed by the plants is greater but the fitting is better during winter. No difference was found by washing leaves with distilled water: this means that PAHs aren't deposited on the surface but are adsorbed in the lipidic layer of the leaves.     

固相膜萃取-气相色谱/离子阱质谱法测定水中17种多环芳烃

利用固相萃取膜富集,气相色谱-离子阱质谱联用法测定水中17种多环芳烃。通过实验表明,该方法操作简便,灵敏度高,精密度好,采用气质联用技术,内标法测定,定性、定量准确。用该方法测定实际样品,平均回收率为80%～113%,17种多环芳烃的方法检出限为0.07～0.23μg/L。     

神木原煤萃取产物中多环芳烃含量的研究

对神术原煤分别用苯及石油醚作萃取溶剂进行索式萃取,采用硅胶柱层析纯化,利用气相色谱/质谱联用仪（GC／MS）分别对上述萃取液的硅胶层析产物进行了解折,并对其中的9种多环芳烃（PAHs）进行了定量测定;研究了不同萃取剂所得萃取液中多环芳烃的分布。结果表明,神木原煤中的PAHs以两环、三环和四环PAHs为主,苯萃取液与石油醚苹取液中PAHs的分布大体相同,但在丰度上有很大差别。     

Multivariate Analysis of Polycyclic Aromatic Compounds in Suspended Particulate

Abstract

The monitoring of air quality today provides a number of parameter values measured as a function of time. In the urban atmosphere, and especially in the particulates, increasing importance is being given to the presence of polycyclic aromatic compounds (PAC), particularly since some are known to be carcinogenic. As the number of measured parameters increases, examining the data and their consequent interpretation becomes more difficult. To overcome such difficulties, numerous statistical techniques have been introduced in chemistry, such as Multivariate Data Analysis (MVDA): Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR). The first technique has been applied in this work to the interpretation of the quality of Augusta (Siracusa, Italy) urban air by measuring the concentration of numerous PAC in the particulates in different sites and at different times. The MVDA has highlighted the similarity between various sampling sites whose data were initially thought to be different. Furthermore, it has allowed a choice of more significant parameters for future PAC monitoring and more suitable sampling site locations.     

Effects of Histidine on Light-Induced DNA Single-Strand Cleavage by Selected Polycyclic Aromatic Hydrocarbons

The combination of UVA light and 1-aminopyrene, 1-hydroxypyrene, 1-hydroxybenzo[ a ]pyrene, 3-aminofluoranthene, 6-aminochrysene, or 5-, 6-, and 7-methylbenz[ a ]anthracenes causes DNA single-strand cleavage. 1-Hydroxypyrene, 1-hydroxybenzo[ a ]pyrene, and 5-methylbenz[ a ]anthracene have been shown to cause DNA cleavage, at least partially, by generating singlet oxygen. Therefore, the presence of histidine, a singlet oxygen quencher, should inhibit the DNA photocleavage. However, the presence of 50 mM histidine greatly enhances the DNA photocleavage caused by these compounds. This effect is due to the inhibition of the photodegradation of the PAH compounds. Therefore, care must be taken when interpreting the singlet oxygen quenching data by histidine. Histidine may coexist with PAHs that have entered the body. The presence of histidine can alter the photochemical reaction and, possibly, the phototoxicity mechanism of the PAHs.     

Polycyclic Aromatic Hydrocarbons in Romanian Baby Foods and Fruits

Levels of polycyclic aromatic hydrocarbons (PAHs) in commercially available baby food and in different sorts of fruits were investigated. PAHs determination was performed by gas chromatography coupled with mass spectrometry (GC/MS). The sum of 15 PAHs varied in baby food from 2.52–6.7 μg/kg and in fruits from 0.40–21.52 μg/kg. Benzo[a]pyrene used as a marker for PAHs contamination was detected in lower levels in baby food than the maximum tolerable limit (1 μg/kg) stated in Commission Regulation no 1881/2006.     

Polycyclic Aromatic Sulfur Heterocycles in Desulfurized Diesel Fuels and Their Separation on a Novel Palladium(II)-Complex Stationary Phase

The lowering of the legal concentration of sulfur in fuels (in the European Union from 150 ppm at present to 50 ppm in 2004) not only affects the concentration but also the pattern of the polycyclic aromatic sulfur heterocycles (PASH) in the fuels. This pattern was studied for 12 diesel samples, most of which have been desulfurized. A separation of the PASHs and the polycyclic aromatic hydrocarbons becomes necessary at such sulfur levels. An efficient liquid chromatographic method for this is presented and involves a Pd(II)-containing complex based on 2-amino-1-cyclopentene-1-dithiocarboxylate covalently bonded to silica. The resultant PASH fraction can be analyzed by gas chromatography/flameionization detection.     

Overview of Polycyclic Aromatic Compounds (PAC)

The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log K_OW), and pK_a are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms.

PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs.

This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs.     

Determination of K ow of Substituted Polycyclic Aromatic Compounds

Octanol-water partition coefficients (K _ow s) of substituted polycyclic aromatic compounds (PACs), anthracene-, pyrene- and quinoline-derivatives, have been determined using HPLC. The determined K _ow s have been compared with results from theoretical fragment methods, developed by Rekker and Mannhold [1] and by Hansch and Leo [2]. The results showed that if these theoretical methods are to be useful with simple substituted PAHs they must be applied differently than normally supposed, due to intramolecular steric conditions. Comparison of the determined K _ow s with measured K _oc values showed that the relationship between K _oc and K _ow is not straightforward, and that prediction of K _oc from K _ow alone will not give results applicable for substituted polycyclic aromatic compounds.     

Fluorescence Emission Properties of Polycyclic Aromatic Compounds in Review

Fluorescence emission behavior of polycyclic aromatic hydrocarbons (PAHs), polycyclic aromatic nitrogen heterocycles (PANHs), polycyclic aromatic sulfur heterocycles (PASHs) and benzofluoranthenes dissolved in organic solvents of varying polarity is reviewed. Measured fluorescence properties are used to divide aromatic solutes into two categories, probe and nonprobe molecules, depending upon whether the molecule's emission intensity ratios vary systematically with solvent polarity. Seventeen polycyclic aromatic hydrocarbon solute probes are identified and possible probe character versus molecular structure correlations are examined. Also discussed are instrumental and chemical artifacts associated with accurate determination of fluorescence emission intensities.     

Dipolarophilic Reactivity of Polycyclic Aromatic Compounds Towards Nitrile Oxides

Mesitonitrile oxide adds to polycyclic aromatic compounds (PACs) such as phenanthrene and pyrene to give mono-cycloadducts. Pyrene does not afford bis-cycloadducts even when a large excess of 1,3-dipole is used. The more reactive benzonitrile oxide does not react with these PACs.     

固相萃取法和GC-MS联用检测石油污染物中17种多环芳烃

文章建立了一种检测石油污染物中多环芳烃的方法。该法采用商品化的硅胶和氧化铝混合填料固相萃取柱对样品中的烷烃和多环芳烃进行分组,实验结果表明,烷烃及多环芳烃的加标回收率在85.6%~104.9%,分组效率优越,可满足实验需求,消除了烷烃对多环芳烃检测的干扰。在该基础上,对石油样品进行净化处理,经过检测,可准确得到石油样品中多环芳烃的含量,石油样品中多环芳烃的加标回收率数据在85.3%~105.9%,RSD(n=5)范围为2.2%~7.3%,方法具有较好的重现性。本方法操作简便、选择性好、灵敏准确,可应用于石油样品中多环芳烃的检测研究。     

Examinations of Dimethyl Sulfoxide-Phase Equilibrium Acidities of Selected Polycyclic Aromatic Compounds

Comparisons of dimethyl sulibxide (DMSO)-phase pK _a's (in parentheses) for 10-cyano-9-methoxymethy-lanthracene (17.35), 10-cyano-9-phenoxymethylanthracene (14.9), 9-cyanomethoxymethylanthracene (20.4), and (α-methoxy) phenylacetonitrile (23.0) with literature DMSO-phase pK _a's for 9-methylanth-racene, 9-methoxymethylanthracene, 9-phenoxymethylanthracene, 9-cyanomethylanthracene, 10-cyano-9-methylanthracene, and phenylacetonitrile (31.1, 30.6, 30.2, 19.7, 20.0, and 21.9, respectively), indicate that: (a) α-methoxy and α-phenoxy substituents acidify 10-cyano-9-methylanthracene; (b) an α-methoxy moiety deacidifies 9-cyanomethylanthracene and phenylacetonitrile; and (c) 10-cyano substituents acidify 9-methylanthracene, 9-methoxymethylanthracene, and 9-phenoxymethylanthracene by 11.1, 13.25, and 15.3 pK _a units, respectively. These data are indicative of steric inhibition of resonance, resonance saturation, and effects due to cross conjugation, in carbanions derived from variously substituted 9-methylanthracenes. DMSO-phase pK _a for phenalene (18.2) and benzanthrene (20.2) have also been determined. In DMSO, phenalene is therefore 4.4 pK units more acidic than its isomeric analogue fluorene (22.6), while benzanthrene is 0.5 pK units less acidic than its isomeric analogue 1,2-benzofluorene (19.7). Specific solvation of the allylic-like phenalenide anion is a likely reason for its enhanced acidity, relative to benzanthrene.     

Activation of Polycyclic Aromatic Compounds by cDNA-Expressed Phase I and Phase II Enzymes

A large number of human and other mammalian xenobiotic-metabolizing enzymes have been expressed in target cells of standard mutagenicity tests, such as Ames's Salmonella typhimurium strains and Chinese hamster V79 cells. These recombinant cells are useful for determining the ability of individual enzymes to activate (or inactivate) a given compound. In contrast to standard S9-mediated test systems, they also allow the detection of mutagenic metabolites that do not penetrate cell membranes--a situation often found with reactive phase II metabolites. We present mutagenicity data for benzo[ a ]pyrene and dibenzo[ a,l ]pyrene in V79-derived cells expressing human cytochrome P450 (CYP) 1A1, 1A2, and 1B1, and for 1-hydroxymethylpyrene, R - and S -1-( f -hydroxyethyl) pyrene, 4-hydroxycyclopenta[ def ]chrysene and N -hydroxy-2-acetylaminofluorene in V79-derived cells and/or Salmonella strains expressing the 11 human sulfotransferases (SULTs) identified. In some cases, allelic variants and orthologous enzymes from other mammalian species were also investigated. The data indicate that mutagenicity of many compounds is detected in the appropriate recombinant systems at extremely low substrate concentrations, that the activation of various promutagens is mediated with high specificity by only one or few enzyme forms, and that substantial differences may occur between alloenzymes from the same species and orthologous enzymes from different species. Such information could be important for understanding differences in susceptibility between tissues, species, individual genetic traits, and physiological states.     

Formation and Lifetime of Polycyclic Aromatic Compounds During a National-Scale Transient Pollution Episode

Concentrations of selected particle-borne parent, alkylated, oxygenated, and nitrated polycyclic aromatic compounds (PACs) have been monitored before, during, and after a large national-scale wood-burning pollution episode (5 November 1994 and 4-5 November 1995). Toluene-modified supercritical CO 2 was used for the extraction of PACs from the collected particulate matter. Analysis was performed using an on-line multidimensional chromatographic technique using coupled liquid and gas chromatography (LC-GC) with loop interface. Comparison of average urban and wood smoke particulate PAC profiles identified a marked change in the ambient PAC profile for the pollution episode period, caused by the change in emission source from predominantly vehicular to wood smoke. A chemical mass balance model has been used to calculate the relative contributions from general urban and wood smoke PAC sources and from them, an estimation of the atmospheric life-time of the PAC emissions has been made. When monitored with 24 hr resolution in 1994, the concentrations of quinone-PAC oxidation products were found to peak 1 day after the maximum concentrations in the parent PAH were recorded, consistent with photochemically driven reactions with singlet state molecular oxygen. When concentrations were monitored on a more frequent basis in 1995, the concentrations of oxygenated species were seen to begin increasing in concentration before sunrise but still peaking after the maximum concentrations of parent PAH were recorded. The nighttime rise in product PAC suggests dark reactions with ozone or the NO 3 radical also may be occurring.     

Standard Reference Materials (SRMs) for the Determination of Polycyclic Aromatic Compounds--Twenty Years of Progress

In 1981 the National Bureau of Standards, now the National Institute of Standards and Technology (NIST), issued the first natural matrix Standard Reference Material (SRM) for the determination of polycyclic aromatic compounds (PACs), SRM 1580 Organics in Shale Oil. In the next 10 years, additional natural matrix SRMs were developed including air and diesel particulate matter, petroleum crude oil, coal tar, sediment, and mussel tissue. The SRMs represented the "first generation" of natural matrix SRMs for the determination of PACs. The SRMs had "certified" values for only 5 to 12 PACs; however, their development established the foundation for the implementation of the "two or more independent analytical techniques" approach for certification of individual PACs in environmental matrices. The requirement for use of different analytical techniques spurred the development of both gas chromatography (GC) and liquid chromatography (LC) approaches for the determination of PACs. Since the mid-1990s, the "second generation" of natural matrix SRMs has been issued by NIST with certified values for over 20 PACs in each material. The greater number of certified values in these SRMs was the result of the combination of measurements using reversed-phase LC with fluorescence detection, multidimensional LC, and GC with mass spectrometric detection using two or more stationary phases with different selectivity for polycyclic aromatic hydrocarbon (PAH) separations. This article discusses the significant developments in analytical methods and chromatographic separation of PAHs during the past 20 years that have resulted in the certification of over 25 SRMs, which are now used worldwide for the validation of analytical methods for the measurement of PACs in environmental matrices.