Direct mass-quantification of particulate deposits of polycyclic aromatic hydrocarbons by Fourier transform imaging microscopy

Successful coupling of imaging microscopy with Fourier transform spectrometry provides a new methodological approach. This was applied to the direct analysis of particulate deposits of polycyclic aromatic hydrocarbons (PAHs). The fluorescence signals of single microscopic particulates were found to be proportional to their mass, obtained from the corresponding HPLC results. Special fluorescence characteristics related to individual particle analysis were studied. The sensitivity of the proposed method to PAHs in soil is in the sub-ppb range, similar to HPLC results. Analysis of inhomogeneous PAH-particulates was demonstrated, as well as the resolution of photochemical products of PAHs. The effects of particulate orientation relative to the detector upon quantification are discussed.     

Rapid and sensitive determination of polycyclic aromatic hydrocarbons in atmospheric particulates using fast high-performance liquid chromatography with on-line enrichment system

A method using on-line enrichment and fast high-performance liquid chromatography (HPLC) with fluorescence detection has been developed and validated for the determination of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate samples. The evaporation step for sample preparation can be eliminated since this system allows the injection of 1000microL of sample solution. PAH recoveries were between 87% and 120% for spiked atmospheric particulate samples. The limit of detection was 0.02-0.23ng/mL (signal/noise ratio=3.3). There was good linear correlation between HPLC peak area and PAH concentration, with a linear range of 0.4-40ng/mL and correlation coefficients >0.997. Furthermore, compared to conventional approaches that include an evaporation step, the method proposed is acceptable for detecting PAHs in atmospheric particulate samples.     

Microwave assisted extraction of polycyclic aromatic hydrocarbons from atmospheric particulate samples

For several years, microwave assisted extraction (MAE) was applied to extract organic compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, etc., from soils, sediments and standard reference materials. Very few authors applied this methodology for the extraction of PAHs from atmospheric particulate matter. In the present study, MAE of polycyclic aromatic hydrocarbons with hexane/acetone (1:1) from real atmospheric particulate samples was investigated and the effect of microwave energy and irradiation time studied. The yields of extracted compounds obtained by microwave irradiation were compared with those obtained using traditional Soxhlet extraction. MAE was evaluated using spiked real atmospheric particulate samples and two standard reference materials. Analytical determinations of PAHs were carried out by high performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. The best recoveries were achieved with a microwave energy of 400 W and an irradiation time of 20 min.     

Headspace single drop microextraction combined with HPLC for the determination of trace polycyclic aromatic hydrocarbons in environmental samples

A new method by combining headspace single drop microextraction (HS-SDME) with HPLC fluorescence detection for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in environmental samples was developed. Aqueous solution of saturated beta-cyclodextrin was used as extraction solvent and five PAHs were employed as target analytes. The factors affecting the extraction efficiency were studied in detail and the optimal extraction conditions were established. Beta-cyclodextrin was found to play two important roles, one is the improvement of extraction efficiency of target analytes and the other is the enhancement of their fluorescence intensities in HPLC fluorescence detection. The detection limits for the target analytes were found to be in the range of 0.004-0.247ng/ml and the relative standard deviations (R.S.D.s) of 5.1-7.1% were obtained. The proposed method was applied to the analysis of trace PAHs in environmental samples with satisfactory results.     

直观推导式演进特征投影法解析多环芳烃的重叠色谱峰

用高效液相色谱法(HPLC)测定多环芳烃时,因芴、苊和菲,茚(1,2,3-cd)芘和苯并(g,h,i)苝的色谱峰严重重叠而影响测定结果。本研究用高效液相色谱-二极管阵列检测器(DAD)和荧光检测器(FLD)测定多环芳烃,在激发波长λex=230nm,发射波长λem=300～500nm范围内采集重叠峰的HPLC-FLD二维色谱数据,再用直观推导式演进特征投影法(HELP)解析它们的重叠色谱峰,分辨结果令人满意。该方法对重叠组分的分辨下限为0.02mg/L。结果表明,用二维色谱荧光数据解析色谱重叠峰,灵敏度更高,可用于环境样品中多环芳烃的测定。     

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.     

Quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair by HPLC with fluorescence detection: a biological monitoring method to evaluate the exposure to PAHs

A high-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair. Fifteen kinds of PAHs classified as priority pollutants by the US EPA were quantified with four perdeuterated PAHs as internal standards. After 50 mg hair samples were washed with n-hexane to remove external contamination of PAHs, the samples were digested in 2.5 M sodium hydroxide. The digests were extracted with n-hexane and then analyzed by HPLC. Eleven kinds of PAHs were identified in hair samples of 20 subjects, and 10 kinds of PAHs were eventually quantified using the internal standards. For anthracene, chrysene and benzo[k]fluoranthene, significant differences were observed between smokers and non-smokers. Although benzo[b]fluoranthene, dibenz[a,h]anthracene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene were observed in the particulates of indoor and outdoor air, they were not detected in all hair samples. The analysis of PAHs in human hair should be useful as a new biomarker to evaluate the exposure to PAHs.     

Determination of polycyclic aromatic hydrocarbons in atmospheric particulate matter of Valencia city

Summary Polycyclic aromatic hydrocarbons (PAHs) were determined in atmospheric particulate matter in 11 sites of the Valencia area and at several times during the year. Sample analysis was carried out by ultrasonic acetonitrile extraction followed by reverse phase HPLC separation and fluorescence detection. The maximum concentration of total PAH developed in winter and spring. Mean values per sampling site varied from 0.193 to 1.668 g/m³ of filtered air. Environmental noise and temperature were determined at those same 11 sites and correlated with PAH levels.     

Analysis of polycyclic aromatic hydrocarbons in atmospheric particulate samples by microwave‐assisted extraction and liquid chromatography

A methodology based on microwave‐assisted extraction (MAE) and LC with fluorescence detection (FLD) was investigated for the efficient determination of 15 polycyclic aromatic hydrocarbons (PAHs) regarded as priority pollutants by the US Environmental Protection Agency and dibenzo(a,l)pyrene in atmospheric particulate samples. PAHs were successfully extracted from real outdoor particulate matter (PM) samples with recoveries ranging from 81.4 ± 8.8 to 112.0 ± 1.1%, for all the compounds except for naphthalene (62.3 ± 18.0%) and anthracene (67.3 ± 5.7%), under the optimum MAE conditions (30.0 mL of ACN for 20 min at 110°C). No clean‐up steps were necessary prior to LC analysis. LOQs ranging from 0.0054 ng/m³ for benzo(a)anthracene to 0.089 ng/m³ for naphthalene were reached. The validated MAE methodology was applied to the determination of PAHs from a set of real world PM samples collected in Oporto (north of Portugal). The sum of particulate‐bound PAHs in outdoor PM ranged from 2.5 and 28 ng/m³.     

Determination of polycyclic aromatic hydrocarbons in water samples using high-performance liquid chromatography with amperometric detection

The determination of polycyclic aromatic hydrocarbons (PAHs) using high-performance liquid chromatography (HPLC) with UV and fluorescence detection has been well established. Although most of the PAHs can be detected by these methods, some environmentally important polyaromatic compounds, such as acenaphthylene, do not show fluorescence and can only be determined by UV detection at higher concentrations. A sensitive and selective determination of acenaphthylene, acenaphthene and the six PAHs listed in the TVO, the German drinking water standard, is also possible by amperometric detection following HPLC separation. The method was applied to the determination of PAHs in different water samples after solid-phase extraction (SPE). The efficiency of the amperometric determination was found to be superior to UV detection (λ = 300 nm).     

On-line concentration and fluorescence determination HPLC for polycyclic aromatic hydrocarbons in seawater samples and its application to Japan Sea

An on?line concentration and fluorescence determination HPLC for polycyclic aromatic hydrocarbons (PAHs) in seawater was proposed. An online concentration column packed with octadecyl polyvinyl alcohol polymer, a pump and a column switching valve were introduced in the conventional HPLC with a fluorescence detector. Only 1.0-100?mL seawater sample was introduced into the concentration column at 1.0?mL?min(-1) without any other pretreatment except filtration. Then the trapped PAHs totally flew into the separation column and eluted separately to be detected fluorogenically. The proposed method had good linearity with correlation coefficients (r) ranged from 0.951 to 0.998, and limits of detection ranged from 0.002 to 0.50?ng?L(-1) for 15 PAHs as 100?mL seawater was loaded. The sensitivity of the method was 10 to 100 times higher than those reported by other works. The proposed method was applied to the determination of PAHs in the seawater samples collected in the Japan Sea with satisfactory results and to check the present benzo[a]pyrene concentration at the beaches in Noto peninsula, Japan polluted with C-heavy oil spilled from the tanker in 1997.     

Identification of polycyclic aromatic hydrocarbons (PAHs) in suspended particulate matter by synchronous fluorescence spectroscopic technique

The synchronous fluorescence (SF) technique has been used in the identification of polycyclic aromatic hydrocarbons (PAHs) from air particulate sample in an urban environment of Delhi, Jawaharlal Nehru University. Suspended particulate matter samples of 24h duration were collected on glass fiber filter papers. PAHs were extracted from the filter papers using dichloromethane (DCM)+hexane with ultrasonication method. Qualitative measurements of the polycyclic aromatic hydrocarbons (PAHs) were carried out using the SF technique at various wavelength intervals (Deltalambda). Due to the difference in chemical structure, each PAH gives specific characteristic spectrum for each Deltalambda. Following PAHs were detected in our measurement: benz(a)anthracene (BaA), pyrene (Pyr), chrysene (Chry), fluoranthene (Flan), phenanthrene (Phen), and benz(ghi)perylene (BghiP). This is in agreement with our earlier work for determination of these PAHs using gas chromatography (GC). The seasonal variation of the PAHs was found to be maximum in winter and minimum during the monsoon.     

Polycyclic aromatic hydrocarbons in waste waters and sewage sludge: Extraction and clean-up for HPLC analysis with fluorescence detection

Summary A modified solid-phase extraction technique using sonication of the adsorbent material instead of the elution normally applied has been compared with two conventional liquid-liquid extraction procedures for the determination of the 16 EPA PAHs in municipal waste waters by means of HPLC coupled with fluorescence detection. Liquid-liquid extraction with cyclohexane proved to be the most efficient and simplest procedure. Clean-up of the waste-water extracts was not considered necessary, because of the high chromatographic resolution of the column and the selectivity of the fluorescence detector. Different organic solvents were also compared for ultrasonic extraction of PAHs from sewage sludge. The best results were obtained by use of acetonitrile. Clean-up of sewage-sludge extracts was not found necessary for accurate quantification of the major PAH components with fluorescence detection. The precision of the whole analytical procedure from extraction to the final determination of PAHs was satisfactory for both waste-water and sewage-sludge samples.     

Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction and liquid chromatography.

This study describes the determination of polycyclic aromatic hydrocarbons (PAHs) in water using high-performance liquid chromatography (HPLC) coupled with fluorescence detection (FLD). Because individual PAHs are generally present in water only at trace levels, a sensitive and accurate determination technique is essential. The separation and detection of five PAHs were run completely within 25 min by the HPLC/FLD system with an analytical C18 column, a fluorescence detection, and acetonitrile-water gradient elution. Calibration graphs were linear with very good correlation coefficients (r > 0.9998), and the detection limits were in the range of 2-6 ng/l for five PAHs. Solid phase microextraction (SPME) was performed for sample pretreatment prior to HPLC-FLD determination, and the governing parameters were investigated. Compared to conventional methods, SPME has high recovery, saves considerable time, and reduces solvents waste. The extraction efficiencies of five PAHs were above 88% and the extraction times were 35 min in one pretreatment procedure. One particular discovery is that 1.5 M sodium monochloroactate (ClCH2COONa) can improve the extraction yield of PAH compounds more than other inorganic salts. The SPME-HPLC-FLD technique provides a relatively simple, convenient, practical procedure, which was here successfully applied to determine five PAHs in water from authentic water samples.     

Determination of polynuclear aromatic hydrocarbons in water by flotation enrichment and HPLC

A method of concentration and determination of several polynuclear aromatic hydrocarbons (PAHs) in water by flotation enrichment and HPLC is described. Triton X-100 was used as the foaming agent to extract the PAHs from water by passage of nitrogen. Reversed-phase liquid chromatography with coupled fluorescence detection was applied to separate and determine these PAHs. Various factors which may affect the recovery of PAHs from water, including pH, temperature and the concentration of Triton X-100 added, are discussed. This simplified method of concentrating PAHs from water has been applied to determine PAHs in water from Lake Erie. The method has practical value for the determination of PAHs in large volumes of water.     

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.     

A model to evaluate half-lives of PAHs naturally occurring on airborne particulate

Constant decay of polycyclic aromatic hydrocarbons (PAHs) adsorbed onto airborne particulate collected in glass fibre filters and exposed to sunlight ranged from 1.8 to 4.4 X 10(-3) (min-1), corresponding respectively to a half-life of 100 and 425 min. Half-life of PAHs appeared to be positively correlated with filter loading. Experimental results showed that decay of PAHs adsorbed on airborne particulate was induced by two concomitant reactions; a photochemical reaction involving the outer layers of collected particulate, and a "dark" reaction that may occur in the inner layers. The constant decays of these two reactions were calculated using a simplified mathematical model. The authors suggest the use of this model to compare chemical stability of airborne PAHs exposed, during their permanence in the atmosphere, to different physical (light intensity, temperature, humidity) as well as chemical conditions (oxidant concentration, chemical composition of particulate).     

Unified Procedure for the Determination of Polycyclic Aromatic Hydrocarbons and Their Nitro Derivatives by Low-Temperature Luminescence

A method was described for determining polycyclic aromatic hydrocarbons (PAHs) and their nitro derivatives (nitro-PAHs) in samples of complex composition using low-temperature luminescence. Fractionation by HPLC was used to separate compounds with similar spectral properties. At the chromatograph inlet, a test sample was purified from weakly retained components additionally preconcentrated on a concentrator cartridge, which was fixed in the injector in place of the sampling loop. Step gradient fractionation was considered, and a table of retention times for PAHs and nitro-PAHs was presented. The the fractional distribution of the analytes was studied. Phosphorescence spectra of some nitro-PAHs were described. The method proposed is comparable in sensitivity to HPLC with the fluorescence detection, but does not require derivatization for determining nitro-PAHs. A table of spectral parameters of analytes suffices for qualitative analysis, as in chromatography–mass spectrometry. However, in distinction to the latter technique, the method described is selective because of the specificity of excitation and emission spectra of each of the analytes.     

Microcomputer-assisted retention prediction system in reversed-phase HPLC

Summary The microcomputer-assisted retention prediction system in C₁₈ reversed-phase HPLC is described. The system is based on the use of the hydrophobic parameter and the correlation factor of alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs) which are highly correlated to their retention in reversed-phase HPLC. The system is evaluated by comparing the retention data between measured and predicted values. One of the typical examples applied for PAH analysis in the extracts of diesel particulate matter shows the high potential of the system investigated.     

Determination of polycyclic aromatic hydrocarbons in edible oils and fats by on-line donor-acceptor complex chromatography and high-performance liquid chromatography with fluorescence detection

Various off-line methods for clean-up and sample enrichment are available for the analysis of polycyclic aromatic hydrocarbons (PAHs) in edible oils and fats. These methods consist of laborious and time consuming procedures. This study reports an on-line method using LC-LC coupling. After clean-up of the sample on a donor-acceptor complex chromatography (DACC) column the PAHs are transferred to and separated on an analytical HPLC column. Quantification is carried out with fluorescence detection. The DACC column clean-up is fast and is carried out during the HPLC run of the previous sample. Compared to the traditional methods this automated on-line method saves considerable time and significantly reduces the amount of solvent waste. The method uses common HPLC equipment and its performance has been evaluated.