Selective immunoclean-up followed by liquid or gas chromatography for the monitoring of polycyclic aromatic hydrocarbons in urban waste water and sewage sludges used for soil amendment

A selective clean-up procedure using immunoaffinity solid-phase extraction was applied for the trace-level determination of polycyclic aromatic hydrocarbons (PAHs) in urban waste water and sewage sludges used for soil amendment. Anti-pyrene antibodies have been immobilized on a silica-based sorbent and the cross-reactivity of the antibodies towards structurally related compounds were allowed to extract the whole class of priority PAHs. The selectivity of the antibodies provided clean extracts from sludges and, therefore, the identification and quantification were shown to be easier using either liquid chromatography (LC) with UV diode array and fluorescence detection in series or gas chromatography-mass spectrometry (GC-MS), although some loss of up to 50% was observed for the clean-up. The identification of the PAHs by matching of UV and MS spectra was greatly improved. The procedure, including immunoclean-up and LC coupled to diode array and fluorescence detection, was validated using certified reference materials with native PAHs of concentrations in the range of 0.57-2.16 mg/kg (dry sludges).     

Evaluation and optimization of extraction and clean-up methods for the analysis of polycyclic aromatic hydrocarbons in peat samples

The analysis of PAH in peat samples is complicated by the high content of organic matter in peat which affects both extraction efficiency and analytical quality. Therefore, we evaluated the efficiencies of three extraction methods (accelerated solvent extraction (ASE), fluidized bed extraction, ultrasonic extraction) and several clean-up techniques in order to find the best set of methods. ASE proved to be the best extraction method. For clean-up, a procedure using aluminium oxide and silica gel showed the highest efficiency, whereas a method originally developed for soil samples failed to remove the peat matrix satisfactorily. With the optimized extraction and clean-up procedure, 170 samples from Canadian bogs were analysed for PAH. With overall recovery rates between 69?±?14 and 89?±?16% and an inaccuracy of ≤20%, the optimized method was a well suitable tool for the analysis of PAH in peat samples.     

Simplified procedures for the analysis of polycyclic aromatic hydrocarbons in water, sediments and mussels

We describe in this paper simple and robust analytical protocols to determine the 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in water, sediment and mussels. For water samples, eight different solid-phase extraction (SPE) sorbents have been compared and among them, C18 provided highest recoveries and limits of detection of 0.3-15 ng/L. For lyophilized sediments, Soxhlet and ultrasonic extraction were compared, and the last one permitted to recover all analytes with highest repetitivity and was validated by analysing a certified reference material. Finally, the analysis of mussels was undertaken using Soxhlet, ultrasonic and pressurized liquid extraction (PLE) and the performance of several clean-up steps are compared. Whereas for the former two, incomplete recovery or losses of some analytes were evidenced, PLE permitted a more efficient extraction and although alkaline digestion was necessary to remove coextracted compounds, the method gave acceptable recoveries and limits of detection of 0.5-7.7 microg/kg dry mass, as for sediments. In all cases, analysis was performed by gas chromatography coupled to mass spectrometry and internal standard quantification was performed using five deuterated PAHs. Each method performance is discussed for the three matrices analysed and the paper reports advantages and disadvantages of each for their routine application in monitoring programs.     

Multi-residue analysis of polycyclic aromatic hydrocarbons, polychlorobiphenyls, and organochlorine pesticides in marine sediments

A multi-residue analysis procedure using microwave-assisted extraction and pre-purification has been developed for the combined analysis of polycyclic aromatic hydrocarbons (PAH), polychlorobiphenyls (PCB), and organochlorine pesticides (OCP) in marine sediments. This procedure has been validated with certified marine sediment. Several surrogate standards have been employed and the use of octachloronaphthalene (OCN) as a surrogate standard for organochlorine determination in this matrix is discussed. The recoveries of all compounds were high (>70%) and the relative standard deviations are of the same order as the certified values. Different analytical problems are discussed, including DDT degradation in gas chromatography and laboratory PCB background levels. Quantification problems encountered for two pesticides (cis-chlordane and trans-nonachlor) were attributed to PAH interference in the GC-ECD chromatogram.     

Evaluation of solid-phase microextraction conditions for the determination of polycyclic aromatic hydrocarbons in aquatic species using gas chromatography

This paper describes a headspace solid-phase microextraction (HS-SPME) procedure coupled to gas chromatography with mass spectrometric detection (GC–MS) for the determination of eight PAHs in aquatic species. The influence of various parameters on the PAH extraction efficiency was carefully examined. At 75 °C and for an extraction time of 60 min, a polydimethylsiloxane–divinylbenzene (PDMS/DVB) fiber coating was found to be most suitable. Under the optimized conditions, detection limits ranged from 8 to 450 pg g⁻¹, depending on the compound and the sample matrix. The repeatability varied between 7 and 15% (RSD). Accuracy was tested using the NIST SRM 1974b reference material. The method was successfully applied to different samples, and the studied PAHs were detected in several of the samples. Figure Headspace SPME sampling followed by GC–MS facilitates routine monitoring of PAHs in aquatic species     

Advanced sample pretreatment for the monitoring of polycyclic aromatic hydrocarbons and extractable organic halogens in waste water. Flow based procedures with chromatomembrane cells

Polycyclic aromatic hydrocarbons (PAH) and extractable organic halogens (EOX) pollute industrial waste waters and need to be controlled continuously by automated procedures. Their sample pretreatment requires extraction first from complex matrices containing surfactants, humic acids, urine and electrolytes besides. When using chromatomembrane cells (CMC) for the extraction with pentane or hexane a flow based system can be established which preconcentrates the pollutants up to ratios of 100:1 at the same time. The extracted compounds become supplied to a gas chromatograph (PAH) using the split/splitless injection or to a combustion furnace (EOX), respectively. An aqueous solution later extracts the hydrogen halides from the exhaust gas for their simultaneous detection with an ion-chromatograph. The limits of lowest detection are attainable in the lower μg l⁻¹ range by matrix adjusted calibration. The CMC is a novel device containing a bloc of biporous PTFE which enables the contact of two immiscible phases. Polar liquids fill the macropores whereas the micropores remain available for non-polar liquids or gases.     

Coupled-column high-performance liquid chromatographic method for the determination of 1-hydroxypyrene in urine of subjects exposed to polycyclic aromatic hydrocarbons

A coupled-column high-performance liquid chromatographic system for integrated, on-line sample processing and the determination of free and conjugated 1-hydroxypyrene in urine has been developed. The method is based on a “tailor-made” copper phthalocyanine-modified porous-glass precolumn packing material, which allows a direct and repeated injection of urine samples and a selective enrichment of trace amounts of particular components. The fully automated method has a low detection limit (0.01 pmol), a quantitative and matrix-independent recovery and a highly reliability, as shown by an interlaboratory comparison of methods.     

Simultaneous analysis of the photocatalytic degradation of polycyclic aromatic hydrocarbons using three-dimensional excitation-emission matrix fluorescence and parallel factor analysis

Polycyclic aromatic hydrocarbons (PAHs) may be photochemically degraded. Monitoring of degradation process of PAHs is carried out by traditional methods, which normally imply time-consuming procedures that do not allow the chemical process to be analyzed in real time. In the present study, photodegradation kinetics of dibenz[a,h]anthracene, benz[a]anthracene, benz[a]pyrene and benz[k]fluorantene were investigated in aqueous solutions under different conditions. A 2³ factorial design was used for optimizing the degradation process.Fluorescence spectroscopy is a fast, cheap and sensitive analytical method, attractive for use in conjunction with chemometric methods; in this case three-way analytical methodology based on fluorescence excitation-emission matrix (EEM) and parallel factor analysis (PARAFAC) was employed. A four-factor PARAFAC model made it possible to resolve the species presents in the degradation mixture and quantify the relative concentration of the analytes throughout the degradation. Several different parameters, such as core consistency, percentage of fit and correlation coefficients between recovered and reference spectra were employed to determine the suitable number of factors for the PARAFAC model. This new methodology allows us to determine satisfactorily the PAHs concentration during the photodegradation in mixtures of arbitrary composition, representing an interesting alternative to the conventional techniques normally used for the monitoring of degradation reactions.     

超声提取-气相色谱-质谱法测定本草香中16种颗粒态多环芳烃含量及其排放特征分析

本草香颗粒态多环芳烃(PAHs)的分析对探究人体健康和环境安全的影响具有重要意义,但目前相关研究主要针对竹签香,对于配方更为复杂、日常使用更为频繁的本草香颗粒态PAHs定量分析研究十分有限且缺少针对性。为了研究本草香颗粒态PAHs的排放因子和排放特征,在自制的试验舱内采集5种本草香燃烧后的颗粒物,通过优化萃取溶剂、超声时间和仪器分析条件,建立了超声提取-气相色谱-质谱(GC-MS)测定本草香燃烧后颗粒物上所吸附的16种PAHs的方法。通过采集0.8 g样品,切取整片滤膜样品,使用正己烷-二氯甲烷(1∶1, v/v)进行超声萃取,经浓缩定容过滤后使用气相色谱-质谱分析,内标法定量。结果表明,16种PAHs在0.1~5.0 μg/mL范围内线性良好(相关系数r²>0.998),方法检出限(MDL)为0.4~3.8 ng/g;低、高2个水平的加标回收率分别为77.4%~99.5%和82.0%~101.3%;相对标准偏差(RSD)为0.7%~7.2%。5种本草香颗粒态PAHs的排放因子为4.60~11.89 μg/g。本草香的16种颗粒态PAHs中菲(Phe)的含量均为最高,所占比例为24.85%~42.59%,其次为荧蒽(Flu)、芘(Pyr)、 \stackrel{艹}{屈} (Chr)、蒽(Ant)。本草香颗粒态PAHs中Phe的含量稳定且占比明显高于其他室内燃烧源,可将Phe作为本草香的颗粒态特征PAHs。颗粒态PAHs主要分布在3环和4环上,3环和4环PAHs占比之和为83.84%~96.31%。颗粒态的Phe/Flu比值可作为辨别不同室内燃烧源中燃香释放源的特征比值。该方法所需样品量少,灵敏度高,前处理操作简便,适用于燃香类产品中PAHs的快速检测,同时为了解本草香颗粒态PAHs分布规律和健康危害提供科学数据。     

Powerful preconcentration method for capillary electrophoresis and its application to analysis of ultratrace amounts of polycyclic aromatic hydrocarbons

For environmental analyses, a high-performance and powerful preconcentration system exceeding 1×10⁷-fold was developed that was composed of a blue cotton method (solid extraction method)/homogeneous liquid–liquid extraction method/on-line concentration method for capillary electrophoresis (CE). This system was named the “triplex concentration system” and it was achieved by finding a new phase-separation phenomenon (homogeneous liquid–liquid extraction) from a water-miscible organic solvent. Parts per trillion levels of polycyclic aromatic hydrocarbons (PAHs) were used as model analytical targets in this study. With the proposed method, 20-L levels of environmental water could be preconcentrated up to 1×10⁷-fold within a maximum of 1 h. The parts per trillion levels of PAHs were easily determined even using UV/CE, which has a serious sensitivity problem, and the detection limit of benzo[a]pyrene was 3.60 ppt. This system was also used as a practical monitoring method for the Miyata River (in Japan).     

Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons

The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.     

Evaluation of gas chromatography columns for the analysis of the 15 + 1 EU-priority polycyclic aromatic hydrocarbons (PAHs)

Three different stationary phases were investigated for the analysis of the 15 + 1 EU-priority polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry. In addition to the most commonly used 5% phenyl methylpolysiloxane, a mid-polar phase (50% phenyl methylpolysiloxane) and a recently commercialised mid-polar to polar phase (Optima® δ-6), were evaluated. Challenging groups of PAHs in terms of separation, such as the pair dibenz[a,h]anthracene-indeno[1,2,3,-cd]pyrene and the two groups benzo[b]fluoranthene-benzo[k]fluoranthene-benzo[j]fluoranthene and cyclopenta[cd]pyrene-benz[a]anthracene-chrysene, were satisfactorily separated by using the mid-polar phase. Moreover, discrimination in terms of peak height for the heaviest PAHs (caused from the strong interaction of these compounds with the stationary phase) was reduced without compromising the resolution of the other target analytes when applying the mid-polar phase in a tailor-made column geometry (20 m?×?0.18 mm internal diameter and 0.14 μm film thickness) in combination with optimised chromatographic conditions. A significant enhancement of the analytical sensitivity for dibenzopyrenes is demonstrated with an almost threefold increase of the signal-to-noise (S/N) ratio for dibenzo[a,h]pyrene, the last eluting PAH. The ability of the selected column to separate potentially interfering PAHs from the target analytes in both solvent solutions and food extracts is demonstrated.     

Modified sampling and analysis method for large volatility range airborne polycyclic aromatic hydrocarbons (PAH) using gas chromatography-mass spectrometry

A sampling method has been developed for the measurement for polycyclic aromatic hydrocarbons in ambient air by gas chromatography isotope dilution mass spectrometry. The method has been designed to measure the largest possible volatility range of PAHs including the abundant naphthalenes. Sample volumes were approx. 500 m³ in size at a sampling rate of approx. 18 m³/h. The sampler contained three sorption stages for the simultaneous capturing of particle bound and low and high volatile gaseous PAH, respectivley. Recoveries of sampling spikes were on average 90%. The detection limit was approx. 5 pg/m³ for the high boiling range PAH. Results obtained showed a quite steady profile for most PAH in background air in The Netherlands. Comparison of abundance ratios with literature data indicate that traffic exhausts are the major source for the PAH in the area.     

Supercritical fluid clean-up of environmental samples for the analysis of polycyclic aromatic hydrocarbons using time-of-flight secondary ion mass spectrometry.

A novel sample-pretreatment method for time-of-flight secondary ion mass spectrometry (TOF-SIMS) was developed using supercritical fluid extraction (SFE). In SFE, the extraction efficiency of a certain organic matter is controlled by the pressure and temperature of supercritical CO2. Two-step SFE (1st step at 10 Mpa, 40 degrees C; 2nd step at 30 MPa, 120 degrees C) was applied to diesel exhaust particles containing many kinds of n-alkanes and aromatic species. n-Alkanes and polycyclic aromatic hydrocarbons (PAHs) were extracted in the 1st and 2nd steps, respectively. This selectivity was utilized for the sample preparation of TOF-SIMS analysis. Diesel exhaust particles after the 1st step of extraction were analyzed with TOF-SIMS, aiming at PAHs as analytical targets. The obtained spectrum was simplified, and mass peaks of individual PAHs were easily assigned, because unwanted compounds, like n-alkanes, were selectively removed by SFE. Furthermore, a simple calculation elucidated the outline of the spectrum.     

Comprehensive analysis of polycyclic aromatic hydrocarbons in wastewater using stir bar sorptive extraction and gas chromatography coupled to tandem mass spectrometry

The objective of this study was the optimization and comparison of two extraction methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in wastewater (WW). A distribution study of the target compounds between the aqueous phase and the suspended particulate matter (SPM) has been performed in order to establish whether the analysis of both phases is necessary. In this sense, the feasibility of stir bar sorptive extraction (SBSE) and solid-phase extraction (SPE) for the determination of 24 PAHs in WW samples has been evaluated. The results demonstrated the suitability of SBSE to perform a comprehensive analysis of liquid samples containing high amounts of SPM, such as in the determination of PAHs in WWs. A gas chromatography triple quadrupole mass spectrometry (GC-QqQ-MS/MS) method has been also optimized for the separation and detection of the target compounds, avoiding the co-elution of some groups of isomers, such as benzo[b], [j] and [k] fluoranthenes and indene[1,2,3-cd]pyrene/dibenz[a,h]anthracene. For that purpose, a specific capillary column developed for PAH determination was used. The SBSE procedure was validated and adequate parameters (such as recovery, linearity, precision, limits of detection and quantification) were obtained. Finally, the validated method was applied to the analysis of real samples collected from an experimental WW treatment plant, detecting some PAHs at concentrations in the range 0.007-0.022 μg L(-1).     

Spontaneous formation of mesoporous silica films using non-surfactant template, and optimization with Doehlert designs, for adsorbent for polycyclic aromatic hydrocarbons

To prepare mesoporous silica thin-films by a simple and environmentally friendly pathway, spontaneous formation of silica thin-films in a sol–gel solution without surfactants was studied. The silica thin-films were prepared by immersing a glass substrate, such as a cylindrical test-tube, into a sol–gel solution containing tetraethoxysilane, water, acetic acid, 2-propanol, and triethylene glycol as a pore-forming agent. The resulting thin-films were transparent. The presence of mesopores was confirmed by field-emission scanning electron microscopy, atomic-force microscopy and nitrogen adsorption–desorption isotherms. The Barrett–Joyner–Halenda plot from the adsorption branch of the isotherms indicated that the pore diameter was 2.6 nm. To illustrate the potential use of the film as an adsorbent, the extraction of polycyclic aromatic hydrocarbons was conducted using the chemically modified silica thin-film coated on a test-tube. The composition of the sol–gel solution was optimized using experimental design, i.e., Doehlert design, and recovery of polycyclic aromatic hydrocarbons.     

Analysis of EU priority polycyclic aromatic hydrocarbons in food supplements using high performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector

High performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector (HPLC/UV-FLD) has been used to set up a method to detect the 15(+1) EU priority polycyclic aromatic hydrocarbons (PAHs) in food supplements covering the categories of dried plants and plant extracts excluding oily products. A mini validation was performed and the following parameters have been determined: limit of detection, limit of quantification, precision, recovery and linearity. They were in close agreement with quality criteria described in the Commission Regulation (EC) No 333/2007 concerning the PAH benzo[a]pyrene in foodstuffs, except the not fluorescent cyclopenta[c,d]pyrene for which the UV detection leads to a higher limit of detection. Analysis of twenty commercial food supplements covering mainly the class of dried plants was performed to evaluate their PAHs contamination levels and to test the applicability of the method to various plant matrices. Fifty percent of analyzed samples showed concentration exceeding 2 μg kg⁻¹ for one or more PAHs.     

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.     

Isolation and analysis of polycyclic aromatic hydrocarbons from natural water using accelerated solvent extraction followed by gas chromatography-mass spectrometry

An innovative analytical procedure for the analysis of polycyclic aromatic hydrocarbons (PAHs) from large-volume water samples is presented. It involves sample preparation, sampling and the elution process in an automated continuous procedure involving the ASE technique. Prior to sampling, a XAD-2 resin column is prepared on the basis of a commercial accelerated solvent extraction (ASE) cartridge so that the resin bed is permanently fixed. Then, the XAD column inside the ASE cartridge is cleaned and conditioned. The sampling procedure involves conventional filtration with subsequent isolation of dissolved PAHs on an XAD-2 resin contained in the ASE cartridge. After sampling, the XAD-2 resin content inside the cartridge is eluted by ASE without any further sample preparation and subsequently reused. In order to validate the procedure, the PAHs were isolated from water samples from the Lake Maggiore (North of Italy) using both XAD-2 resin adsorption and hexane liquid-liquid extraction according to the International Standard Methodology ISO 17993. The mean percentages of deviation between concentrations obtained by both methodologies range from 6% for benzo(a)pyrene to 15% for fluoranthene and benzo(b,k)fluoranthene. Compared to the traditional techniques, this procedure offers numerous practical advantages: easy to perform, fast, savings in solvent volume and in time, all steps are fully automated thus avoiding any XAD-2 resin manipulation during and between steps and moreover, low detection limits were provided (0.001 ng l⁻¹ for chrysene, benzo(b,k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene, and 0.01 ng l⁻¹ for acenaphthylene and fluoranthene).This procedure was developed in the frame of a project aimed at evaluating the diffuse input of organic contaminants in the Lake Maggiore.