Determination of nitro-polycyclic aromatic hydrocarbons in atmospheric aerosols using HPLC fluorescence with a post-column derivatisation technique

The objective of this study was to develop an efficient and sensitive analytical protocol for the determination of nitrated polycyclic aromatic hydrocarbons (NPAHs) in aerosol samples. The separation of 16 NPAH (mono-and dinitro-PAH) was achieved by reversed-phase high-performance liquid chromatography (HPLC) followed by on-line reduction of the NPAHs to their corresponding amino polycyclic aromatic hydrocarbons (APAHs) and quantification by fluorescence detection. The main factors affecting the on-line reduction efficiency, such as the flow rate, the temperature, the position and packing of the reduction column were evaluated and optimised. The optimal conditions obtained were: packing of the reduction column with Pt-Al(2)O(3); a reduction column oven temperature of 90 degrees C; a flow rate of 0.8 mL min(-1). The resulting detection limits of the method ranged between 0.06 (2 NN) and 1.25 microg L(-1) (1.8 DNN), with an uncertainty of about 6%. The lifetime of the reduction column was identical to that of a typical analytical column. This analytical method was applied to particulate matter samples collected during December 2005 and August 2006 in Strasbourg (Alsace, eastern France). The NPAH concentrations observed for this urban site showed that the compounds are more abundant during winter (average of 534 pg m(-3)) than during summer (average of 118 pg m(-3)). 1-Nitropyrene was the predominant NPAH species, independent of season.     

Simultaneous determination by ultra-performance liquid chromatography–atmospheric pressure chemical ionization time-of-flight mass spectrometry of nitrated and oxygenated PAHs found in air and soot particles

An ultra-performance liquid chromatographic-atmospheric pressure chemical ionization time-of-flight mass spectrometric (UPLC-APCIToFMS) method for rapid analysis of twelve nitrated polycyclic aromatic hydrocarbons (NPAHs) and nine oxygenated polycyclic aromatic hydrocarbons (OPAHs) in particle samples has been developed. The extraction step using pressurized liquid extraction was optimized by experimental design methods and the concentrated extracts were analyzed without further clean-up. Matrix effects resulting in suppression or enhancement of the response during the ionization step were not observed. The suitability of the developed method is demonstrated by analysis of six different particle samples including standard reference materials, atmospheric particles collected by a high-volume sampler at an urban background site, and a soot sample from a burner. Results from these measurements showed clear differences between the different kinds of samples. Concentrations from reference materials are in good agreement with those from previous studies. Additionally a clear seasonal trend could be observed in atmospheric NPAH and OPAH concentrations found in real samples, with higher concentrations in winter.     

Determination of 1,3-, 1,6-, 1,8-dinitropyrene and 1-nitropyrene in airborne particulate by column liquid chromatography with electrochemical detection

Nitrated polycyclic aromatic hydrocarbons (NPAHs) in airborne particulate were determined by column liquid chromatography with electrochemical detection. NPAHs were extracted ultrasonically prior to being injected into the separation system. A reversed-phase C18 column was used to separate the NPAHs with an aqueous eluent containing acetonitrile and sodium monochloroacetate as buffer. Calibration graphs were linear with very good correlation coefficients (r>0.999) and the detection limits were ca. 20 pg for all analytes. The proposed method provides a relatively simple and convenient procedure for determining the NPAHs in airborne particulate.     

Retrospective analyses of atmospheric polycyclic and nitropolycyclic aromatic hydrocarbons in an industrial area of a western site of Japan.

Thirteen polycyclic aromatic hydrocarbons (PAHs) and four nitropolycyclic aromatic hydrocarbons (NPAHs) on the surfaces of airborne particulates, which were collected at an industrial area of a western site of Japan during periods from 1976 to 1998, were retrospectively analyzed. PAHs and NPAHs were extracted from airborne particulates using hexane with ultrasonication, and then analyzed by HPLC systems with fluorescence detection and chemiluminescence detection, respectively. The total concentrations (mean +/- SD, n = 34) were 15.54 +/- 21.24 ng/m3 for PAHs and 5.85 +/- 8.16 pg/m3 for NPAHs. The concentrations of PAHs and NPAHs were found to be highest during the period between 1979 and 1982, and then reduced. The annual concentrations of PAHs and NPAHs were highly correlated with those of air pollutants from motor vehicle origin, such as carbon monoxide, suspended particulates and non-methane hydrocarbons. The results suggested that motor vehicle emissions were one of the predominant sources of atmospheric PAHs and NPAHs.     

Trace determination of nitrated polycyclic aromatic hydrocarbons using liquid chromatography with on-line electrochemical reduction and fluorescence detection

An efficient clean-up procedure coupled with a high performance liquid chromatography (HPLC) with on-line electrochemical (EC) reduction and fluorescence detection (FLD) was developed to quantify nitrated polycyclic aromatic hydrocarbons (NPAHs) in the airborne particulate. In this process, NPAHs were extracted ultrasonically followed by analysis by using a reversed phase column with an aqueous eluent containing 70% aqueous acetonitrile and sodium monocholoroacetate as a buffer solution. The extraction efficiencies were above 83% for 1-nitropyrene and 1,3-dinitropyrene (1,3-DNP) 1,6-DNP, and 1,8-DNP, and calibration graphs were linear with very good correlation coefficients (r>0.999) and the detection limits were in the range of 1.0-2.2 pg for dinitropyrenes and nitropyrene. The proposed method provides a relatively simple and convenient procedure for determining the NPAHs samples in airborne particulate.     

Determination of oxygenated polycyclic aromatic hydrocarbons in atmospheric aerosol samples by liquid chromatography-tandem mass spectrometry

In this paper, the development of an analytical method using liquid chromatography-tandem mass spectrometry (LC-MS-MS) with atmospheric pressure chemical ionization (APCI) for the determination of 17 oxygenated polycyclic aromatic hydrocarbons (OPAH) is described. These OPAH include ketones, pyrones and diketones. The APCI interface parameters have been optimized for maximum sensitivity. Positive ion mode was proved to be most sensitive for ketones and pyrones while negative ion mode gave better detection limits for target diketones. The detection limits of the method ranged from less than 1.20microg L(-1) for several OPAH solutions (between 0.10 and 0.70microg L(-1) for positive mode and between of 0.19 and 1.20microg L(-1) for negative mode). The analytical method was applied particulate matter (PM(2.5)) samples collected over 24-48h periods between March 2005 and June 2005 in Tempe (Arizona, USA). Before analysis aerosol samples were solvent extracted and concentrated to a final volume of 1mL of methanol. OPAH concentrations observed for this urban site ranged from 0.22 to 3.60ngm(-3).     

Determination of oxygenated and native polycyclic aromatic hydrocarbons in urban dust and diesel particulate matter standard reference materials using pressurized liquid extraction and LC–GC/MS

The objective of this study was to develop a novel analytical chemistry method, comprised of a coupled high-performance liquid chromatography–gas chromatography/mass spectrometry system (LC–GC/MS) with low detection limits and high selectivity, for the identification and determination of oxygenated polycyclic aromatic hydrocarbons (OPAHs) and polycyclic aromatic hydrocarbons (PAHs) in urban air and diesel particulate matter. The linear range of the four OPAHs, which include 9,10-anthraquinone, 4H-cyclopenta[def]phenanthrene-4-one, benzanthrone, and 7,12-benz[a]anthraquinone, was 0.7 pg–43.3 ng with limits of detection (LODs) and limits of quantification (LOQs) on the order of 0.2–0.8 and 0.7–1.3 pg, respectively. The LODs in this study are generally lower than values reported in the literature, which can be explained by using large-volume injection. The recoveries of the OPAHs spiked onto glass fiber filters using two different pressurized liquid extraction (PLE) methods were in the ranges of 84–107 and 67–110 %, respectively. The analytical protocols were validated using the following National Institute of Standards and Technology standard reference materials: SRM 1649a (Urban Dust), SRM 1650b (Diesel Particulate Matter), and SRM 2975 (Diesel Particulate Matter, Industrial Forklift). The measured mass fractions of the OPAHs in the standard reference materials (SRMs) in this present study are higher than the values from the literature, except for benzanthrone in SRM 1649a (Urban Dust). In addition to the OPAHs, 44 PAHs could be detected and quantified from the same particulate extract used in this protocol. Using data from the literature and applying a two-sided t test at the 5 % level using Bonferroni correction, significant differences were found between the tested PLE methods for individual PAHs. However, the measured mass fractions of the PAHs were comparable, similar to, or higher than those previously reported in the literature.     

Pollution characteristics of ambient PM2.5-bound PAHs and NPAHs in a typical winter time period in Taiyuan

The pollution characteristics of ambient fine particulate matter（PM2.5） containing polycyclic aromatic hydrocarbons（PAHs） and nitrated PAHs（NPAHs） in samples collected during a typical winter time period in Taiyuan of China were investigated.The obtained results revealed that the mean mass concentrations of PM2.5,SPAHs（sum of 16 PAHs） and SNPAHs（sum of 3 NPAHs） on PM2.5were161.4 mg/m3,119.8 ng/m3and 0.446 ng/m3,respectively.Diagnostic ratios of PAHs and NPAHs implied that coal consumption might be the main source of the PM2.5pollution.The measured PM2.5mass concentrations,BaP equivalent toxicity（28.632 ng/m3） and individual carcinogenicity index（3.14 10 5） were much higher than those of the recommended safety standards.     

Isolation of neutral and acidic lipid biomarker classes for compound-specific-carbon isotope analysis by means of solvent extraction and normal-phase high-performance liquid chromatography

An analytical method for the quantitative determination of neutral and acidic lipid biomarkers in particulate and sediment samples has been developed. The method involves a first step with solvent extraction to isolate the neutral from the acidic compounds and a second step using normal-phase HPLC on a Nucleosil silica column to separate four different classes of neutral compounds: (1) aliphatic hydrocarbons, (2) aromatic hydrocarbons, (3) ketone compounds and (4) sterol and alcohol compounds. Recoveries of the individual spiked lipid biomarkers for the whole analytical procedure ranged from 88 to 106% for fatty acids, from 50 to 60% for aliphatic hydrocarbons (> or = n-C17), from 50 to 60% for polycyclic aromatic hydrocarbons (PAHs) (> or = 3 rings), 83% for friedelin and 60-80% for the sterol and alcohol compounds. The isolated compound classes were analysed by gas chromatography-combustion-isotope ratio mass spectrometry to measure the stable carbon isotope ratios in the individual compounds. The method enables the isolation of compound classes without fractionation for compound-specific carbon isotope analysis (delta13C). This analytical protocol has been applied, and proved suitable, for the determination of lipid biomarkers (sterols, fatty alcohols and fatty acids) in marine particulate material and for the determination of PAHs in sediment samples.     

Thermodynamic and kinetic characterization of a bridged-ethylene hybrid C18 stationary phase

In this study, a series of polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing polycyclic aromatic hydrocarbons (NPAHs) is separated on a hybrid stationary phase using methanol and acetonitrile mobile phases. Temperature is varied from 283 to 313 K in order to determine thermodynamic and kinetic parameters of the separation. Thermodynamic behavior is characterized by the retention factor and associated changes in molar enthalpy, whereas kinetic behavior is characterized by the rate constants and associated activation energies. In this study, the retention factors for the NPAHs are smaller than those for the parent PAHs in methanol, while they are more similar to the parent PAHs in acetonitrile. The changes in molar enthalpy are very similar for all solutes, yet are more negative in acetonitrile than in methanol. The rate constants for the NPAHs are smaller than those for their parent PAHs in both mobile phases. Moreover, the rate constants in acetonitrile are one to four orders of magnitude smaller than those in methanol. Based on these thermodynamic and kinetic results, the hybrid stationary phase is compared to traditional silica stationary phases. In addition, the relative contributions from the partition and adsorption mechanisms are discussed.     

An analytical investigation of 24 oxygenated-PAHs (OPAHs) using liquid and gas chromatography–mass spectrometry

We developed two independent approaches for separation and quantitation of 24 oxygenated polycyclic aromatic hydrocarbons (OPAHs) using both liquid chromatography-atmospheric pressure chemical ionization/mass spectrometry (LC-APCI/MS) and gas chromatography-electron impact/mass spectrometry (GC-EI/MS). Building on previous OPAH research, we examined laboratory stability of OPAHs, improved existing method parameters, and compared quantification strategies using standard addition and an internal standard on an environmental sample. Of 24 OPAHs targeted in this research, 19 compounds are shared between methods, with 3 uniquely quantitated by GC-EI/MS and 2 by LC-APCI/MS. Using calibration standards, all GC-EI/MS OPAHs were within 15 % of the true value and had less than 15 % relative standard deviations (RSDs) for interday variability. Similarly, all LC-APCI/MS OPAHs were within 20 % of the true value and had less than 15 % RSDs for interday variability. Instrument limits of detection ranged from 0.18 to 36 ng mL^?1 on the GC-EI/MS and 2.6 to 26 ng mL^?1 on the LC-APCI/MS. Four standard reference materials were analyzed with each method, and we report some compounds not previously published in these materials, such as perinaphthenone and xanthone. Finally, an environmental passive sampling extract from Portland Harbor Superfund, OR was analyzed by each method using both internal standard and standard addition to compensate for potential matrix effects. Internal standard quantitation resulted in increased precision with similar accuracy to standard addition for most OPAHs using 2-fluoro-fluorenone-¹³C as an internal standard. Overall, this work improves upon OPAH analytical methods and provides some considerations and strategies for OPAHs as focus continues to expand on this emerging chemical class.

Polycyclic aromatic hydrocarbons (PAHs) in a coal tar standard reference material—SRM 1597a updated

SRM 1597 Complex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar, originally issued in 1987, was recently reanalyzed and reissued as SRM 1597a with 34 certified, 46 reference, and 12 information concentrations (as mass fractions) for polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) including methyl-substituted PAHs and PASHs. The certified and reference concentrations (as mass fractions) were based on results of analyses of the coal tar material using multiple analytical techniques including gas chromatography/mass spectrometry on four different stationary phases and reversed-phase liquid chromatography. SRM 1597a is currently the most extensively characterized SRM for PAHs and PASHs.     

Catalytic hydrogenation of benzo(a) and benzo(e) pyrenes. Analysis of the hydrogenated products by charge transfer chromatography and HPLC on amino bonded phase

Summary Hydroaromatics (partially hydrogenated polycyclic aromatic hydrocarbons) generated in the course of the process play an important role in the catalytic hydroliquefaction of coal. A difficult analytical task is to identify and to quantify these hydroaromatics among the preponderant polycyclic aromatic hydrocarbons. Generally speaking, the method carried out uses the specific separation of hydroaromatic by charge transfer chromatography. Structural identification is effected by using gas chromatography, alone or coupled with mass spectrometry, and HPLC on amino bonded phase with UV detection.As an aid to obtaining the standard compounds that are essential in that work, this paper describes the application of the above analytical procedure to the catalytic hydrogenation products (RhCl₃/NaBH₄ and Pd/C) of benzo(a) and benzo(e)pyrenes.     

Trace analysis of polycyclic aromatic hydrocarbons in suspended particulate matter by accelerated solvent extraction followed by gas chromatography–mass spectrometry

An analytical procedure based on extraction by accelerated solvent extraction (ASE) followed by gas chromatography–mass spectrometry (GC/MS) analysis has been developed for the determination of particulate polycyclic aromatic hydrocarbons (PAHs) from large-volume water samples (20 L). The effect of temperature and number of cycles on the efficiency of ASE was investigated: the best results were obtained by using a temperature of 100°C and one static cycle. A mixture of hexane/acetone 1:1 (v/v) was used as extraction solvent. Mean total method recovery under optimized conditions was 85%. The developed methodology was applied to the analysis of suspended particulate matter from Lake Maggiore waters (north of Italy). Mean PAH concentrations in suspended particulate matter from Lake Maggiore ranged from 0.2 ng L⁻¹ for anthracene to 18.7 ng L⁻¹ for naphthalene.     

全二维气相色谱-飞行时间质谱联用技术分析重馏分油中芳烃组成

通过对升温速度、二维补偿温度、调制周期等关键实验参数的优化,建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析重馏分油中芳烃组分的方法,得到了重馏分油芳烃组分按环数分布的二维点阵图。根据谱库检索、标准化合物对照及文献报道,对重馏分油芳烃组分中菲、甲基菲及芘、苯并蒽等常见多环芳烃(PAH)进行了准确定性,并将该方法应用到重馏分油加氢处理工艺研究中,对菲、芘的加氢处理产物进行了定性分析。该研究为重馏分油芳烃组分的准确定性提供了新的技术手段,为加深对油品加氢规律的认识提供了技术支持。全二维气相色谱与普通一维色谱对比,在重馏分油的芳烃组分分析上体现了极大优势。     

Simultaneous liquid chromatographic determination of 39 polycyclic aromatic hydrocarbons in indoor and outdoor air and application to a survey on indoor air pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.     

Optimization of an improved analytical method for the determination of 1-nitropyrene in milligram diesel soot samples by high-performance liquid chromatography-mass spectrometry

A method for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs) in diesel soot by high-performance liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization (APCI) and detection by ion-trap following ultrasonic extraction is described. The determination of 1-nitropyrene that it is the predominant NPAH in diesel soot was emphasized. Vaporization and drying temperatures of the APCI interface, electronic parameters of the MS detector and the analytical conditions in reversed-phase HPLC were optimized. The patterns of fragmentation of representative NPAHs were evaluated by single and multiple fragmentation steps and negative ionization led to the largest signals. The transition (247-->217) was employed for quantitative analysis of 1-nitropyrene. Calibration curves were linear between 1 and 15 microgL(-1) with correlation coefficients better than 0.999. Typical detection limit (DL) of 0.2 microgL(-1) was obtained. Samples of diesel soot and of the reference material (SRM-2975, NIST, USA) were extracted with methylene chloride. Recoveries were estimated by analysis of SRM 2975 and were between 82 and 105%. DL for 1-nitropyrene was better than 1.5 mg kg(-1), but the inclusion of an evaporation step in the sample processing procedure lowered the DL. The application of the method to diesel soot samples from bench motors showed levels 相似文献   

Particle-size distribution of polycyclic aromatic hydrocarbons in urban air in southern Spain

The size distribution of polycyclic aromatic hydrocarbons (PAH) was determined for airborne particles from a large city with high vehicular traffic. The analytical method was optimised and validated using NIST standard reference material (SRM 1649a Urban Dust). The 16 priority PAH listed in the US-EPA were Soxhlet-extracted from filtered particulate matter and then fractionated using on-column chromatography. The aromatic fraction was quantified by gas chromatography-mass spectrometry. Real samples of particles collected in Seville (Spain) were analysed using the validated method. Values for the total concentration of PAH in the air, as well as the concentrations of each PAH in six particle-size ranges were obtained. Values of the PAH in TSP, PM₁₀, PM_2.5 and PM₁ were assessed.     

Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid‐phase extraction coupled with gas chromatography and mass spectrometry

Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid‐phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid‐phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0–1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015–0.591 and 0.045–1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1‐monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m^?3. 9,10‐Dichloroanthracene and 1‐monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water.     

Determination of polycyclic aromatic compounds in fish tissue

A method is presented for the analysis of polycyclic aromatic hydrocarbons (PAHs), polycyclic aromatic sulfur heterocycles (PASHs), and basic polycyclic aromatic nitrogen heterocycles (PANHs) in fish. The analytical procedure includes Soxhlet extraction of prepared fish tissue with methylene chloride followed by gel permeation chromatography (GPC) using Bio-beads SX-3. For PAHs/PASHs, further cleanup is performed using adsorption chromatography on Florisil (5% water deactivated) and elution with hexane. For basic PANHs further cleanup of the fish extracts after GPC is achieved using liquid-liquid partitioning with 6 M hydrochloric acid and chloroform and then basifying the aqueous phase and extracting it with chloroform. Analysis of fortified fish samples was performed using capillary gas chromatography with flame ionization detection and capillary gas chromatography-mass spectrometry. Good agreement was observed for both methods of analysis when applied to fish samples fortified with PAHs, PASHs and basic PANHs at 0.1 to 1 microgram/g, suggesting that the method is effective at removing interfering biogenic compounds prior to analysis. Average recovery of PAHs/PASHs from fortified fish tissue was 87% and 70% for fish tissue fortified at 0.24-1.1 and 0.024-0.11 microgram/g, respectively. Average recovery for basic PANHs was 97% for fish fortified at 1.2-1.4 micrograms/g.