Determination of polycyclic aromatic hydrocarbons in aqueous samples by microwave assisted headspace solid-phase microextraction and gas chromatography/flame ionization detection

The novel pretreatment technique, microwave-assisted heating coupled to headspace solid-phase microextraction (MA-HS-SPME) has been studied for one-step in situ sample preparation for polycyclic aromatic hydrocarbons (PAHs) in aqueous samples before gas chromatography/flame ionization detection (GC/FID). The PAHs evaporated into headspace with the water by microwave irradiation, and absorbed directly on a SPME fiber in the headspace. After being desorbed from the SPME fiber in the GC injection port, PAHs were analyzed by GC/FID. Parameters affecting extraction efficiency, such as SPME fiber coating, adsorption temperature, microwave power and irradiation time, and desorption conditions were investigated.Experimental results indicated that extraction of 20 mL aqueous sample containing PAHs at optional pH, by microwave irradiation with effective power 145 W for 30 min (the same as the extraction time), and collection with a 65 μm PDMS/DVB fiber at 20 °C circular cooling water to control sampling temperature, resulted in the best extraction efficiency. Optimum desorption of PAHs from the SPME fiber in the GC hot injection port was achieved at 290 °C for 5 min. The method was developed using spiked water sample such as field water with a range of 0.1-200 μg/L PAHs. Detection limits varied from 0.03 to 1.0 μg/L for different PAHs based on S/N = 3 and the relative standard deviations for repeatability were <13%. A real sample was collected from the scrubber water of an incineration system. PAHs of two to three rings were measured with concentrations varied from 0.35 to 7.53 μg/L. Recovery was more than 88% and R.S.D. was less than 17%. The proposed method is a simple, rapid, and organic solvent-free procedure for determination of PAHs in wastewater.     

Determination of polycyclic aromatic hydrocarbons in waste water by off-line coupling of solid-phase microextraction with column liquid chromatography

A new method for the determination of polycyclic aromatic hydrocarbons (PAHs) in waste water using solvent-free solid-phase microextraction (SPME) is described. The PAHs are extracted with a 100 microm polydimethylsiloxane (PDMS) fiber, desorbed in 40 microl acetonitrile and measured with LC and fluorescence detection. The detection limits of this very simple method under the given conditions (extraction from 5 ml sample, extraction time 1 h) are in the range of 1-6 ng l(-1). The standard deviations (n = 6) at a concentration level of 0.8 microg l(-1) are between 1.8 and 14.4%. The procedure was used for the determination of PAHs in contaminated water samples.     

Solid-phase microextraction of benzimidazole fungicides in environmental liquid samples and HPLC–fluorescence determination

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection was optimized for extraction and determination of four benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and fuberidazole) in water. We studied extraction and desorption conditions, for example fiber type, extraction time, ionic strength, extraction temperature, and desorption time to achieve the maximum efficiency in the extraction. Results indicate that SPME using a Carboxen–polydimethylsiloxane 75 μm (CAR–PDMS) fiber is suitable for extraction of these types of compound. Final analysis of benzimidazole fungicides was performed by HPLC with fluorescence detection. Recoveries ranged from 80.6 to 119.6 with RSDs below 9% and limits of detection between 0.03 and 1.30 ng mL⁻¹ for the different analytes. The optimized procedure was applied successfully to the determination of benzimidazole fungicides mixtures in environmental water samples (sea, sewage, and ground water).     

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.     

苯基修饰二氧化硅纳米片纤维的制备及其对多环芳烃的固相微萃取

采用水热处理和溶胶-凝胶法在镍钛合金（NiTi）纤维表面组装了二氧化硅纳米片（SiO₂NFs）,成功制备了新型SiO₂纤维涂层,并用苯基三氯硅烷进行了自组装表面修饰,得到了可用于固相微萃取（SPME）的NiO/TiO₂@SiO₂NFs-Ph纤维。将制备的SPME纤维与高效液相色谱联用,通过对典型芳香化合物的分析评价了所制备纤维的萃取性能。该纤维对多环芳烃（PAHs）具有较高的萃取率和良好的萃取选择性。实验优化了pH值、搅拌速率、萃取温度、萃取时间和离子强度对PAHs萃取率的影响。在优化条件下,5种PAHs在各自的范围内呈良好的线性关系,相关系数（r）大于0.999,检出限为0.013~0.108 μg/L。使用单根纤维对含有50 μg/L PAHs的加标水样进行萃取,其含量的日内及日间RSD分别为4.1%~5.9%和4.8%~6.8%。实际环境水样中5种PAHs在10 μg/L和30 μg/L加标水平下的加标回收率分别为90.8%~105.7%和93.6%~103.1%。该法制备的NiO/TiO₂@SiO₂NFs-Ph纤维稳定性高、制备重现性好,适用于环境水样中目标PAHs的富集和测定。     

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).     

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.     

复杂基体中痕量多环芳烃分析测定方法的研究进展

介绍了环境样品（水和土壤）以及植物油中痕量多环芳烃的分析检测方法。对样品的预处理过程和分析方法做了评价。采用一些新的预处理方法（包括液相色谱法、固相萃取法、超临界二氧化碳萃取法）,并结合色谱-质谱在线联用分析检测方法能够获得比较理想的分析结果。引用文献52篇。     

Use of ionic liquid aggregates of 1-hexadecyl-3-butyl imidazolium bromide in a focused-microwave assisted extraction method followed by high-performance liquid chromatography with ultraviolet and fluorescence detection to determine the 15+1 EU priority PAHs in toasted cereals ("gofios")

A focused-microwave assisted extraction method using aggregates of the ionic liquid (IL) 1-hexadecyl-3-butylimidazolium bromide (HDBIm-Br) followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and single-channel fluorescence detection (FLD) has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in toasted cereals (“gofios”) of different nature (wheat, barley, rye, and maize corn) from the Canary Islands, Spain. The optimized HPLC-UV-vis/single-channel FLD method takes 40 min for the chromatographic run with limits of detection varying between 0.02 and 4.01 ng mL⁻¹ for the fluorescent PAHs from the European Union (EU) priority list in foods, and 20.5 ng mL⁻¹ for the non-fluorescent PAH cyclopenta[c,d]pyrene (CPP). The optimized microwave step presented extractions recoveries ranging from 70.1 to 109% and precision values lower than 12.6% (as relative standard deviation), using an extraction time of 14 min. The extraction method also utilizes low amounts of sample (0.1 g), and low amounts of IL (77 mg), avoiding completely the use of organic solvents.     

A comparison of the performance of two chromatographic and three extraction techniques for the analysis of PAHS in sources of drinking water

The aim of this work is to establish a sensitive and reliable method for the analysis of the 16 priority Environmental Protection Agency-defined polycyclic aromatic hydrocarbons (PAHs) found in water samples. Gas chromatography (GC)-mass spectrometry (MS) and high-performance liquid chromatography (HPLC)-fluorescence detection (FLD)-UV techniques are optimized to obtain an adequate resolution of all compounds. Validation of the methods is carried out, and a good performance is observed for both techniques. The HPLC-FLD-UV technique is somewhat more sensitive than the GC-MS technique for the determination of PAHs; thus, the HPLC-FLD-UV method is used to follow up both the solid-phase extraction (SPE) analysis using cartridges and discs and the liquid-liquid extraction (LLE), which are also evaluated for the extraction of the PAHs. Low recoveries between 43% and 79% are obtained using SPE cartridges, and higher values are obtained using SPE discs (56-96%) and LLE (60-105%). Better results are obtained using the LLE technique, and, thus, analysis of real water samples is carried out using this technique. LODs between 0.6 and 21 ng/L and relative standard deviations less than 15% are obtained using a spiked water sample analyzed using the full LLE HPLC-FLD-UV method.     

Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

A robust procedure for the determination of 16 US EPA PAHs in both aqueous (e.g. wastewaters, industrial discharges, treated effluents) and solid samples (e.g. suspended solids and sludge) from a wastewater treatment plant (WWTP) is presented. Recovery experiments using different percentages of organic modifier, sorbents and eluting solvent mixtures were carried out in Milli-Q water (1000 mL) spiked with a mixture of the PAH analytes (100 ng/L of each analyte). The solid phase extraction (SPE) procedures applied to spiked waste water samples (1000 mL; 100 ng/L spiking level) permitted simultaneous recovery of all the 16PAHs with yields >70% (6-13% RSD). SPE clean up procedures applied to sewage and stabilized sludge extracts, showed percent recoveries in the range 73-92% (7-13% RSD) and 71-89% (7-12% RSD), respectively. The methods were used for the determination of PAHs in aqueous and solid samples from the WWTP of Fusina (Venice, Italy). Mean concentrations, as the sum of the 16PAHs in aqueous and suspended solid samples, were found to be approx. in the 1.12-4.62 microg/L range. Sewage and stabilized sludge samples contained mean PAH concentrations, as sum of 16 compounds, in the concentration range of 1.44-1.26 mg/kg, respectively. Extraction and clean up procedures for sludge samples were validated using EPA certified reference material IRM-104 (CRM No. 912). Instrumental analyses were performed by coupling HPLC with UV-diode array detection (UV-DAD) and fluorescence detection (FLD).     

固相微萃取-高效液相联用分析环境水样中的痕量■

 应用固相微萃取与高效液相联用技术 (SPME HPLC)分析了环境水样中的痕量 艹屈 。对SPME的条件如萃取时间、萃取温度、离子强度、解吸方式、解吸溶剂、解吸时间和HPLC条件进行了优化 ,建立了SPME HPLC分析环境水样中痕量 艹屈 的方法 ,并将其用于分析自来水、雨水、矿泉水和江水等实际水样。方法的线性范围为 0 0 13μg/L～ 3 0 μg/L ,检出限为 2 7ng/L ,相对标准偏差 (RSD ,n =6 )为 5 6 % ,回收率为 10 3 2 %～ 119 3%。该方法适合于环境水样中痕量 艹屈 的分析 ,体现了SPME在样品前处理中快速、灵敏、简单、无溶剂的特点。     

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。     

Coupling of a Modified In-Tube Solid Phase Microextraction Technique with High Perfor- mance Liquid Chromatography-Fluorescence Detection for the Ultra-Trace Determination of Polycyclic Aromatic Hydrocarbons in Water Samples

A modified in-tube solid phase microextraction (SPME) technique in conjunction with a high performance liquid chromatography (HPLC) was developed for the trace determination of polycyclic aromatic hydrocarbons (PAHs) in water samples. The extraction device contained a regular HPLC syringe, replacing the metallic needle by two concentric fused silica capillary tubes. The capillary tubes were coated with polydimethylsiloxane (PDMS) as the sorbent and were attached to the syringe by a homemade interface made from polyether ether ketone (PEEK). The sorption of analytes was achieved by frequent withdrawing and ejecting the water sample from/into a vial via the capillary tubes. For the desorption step, an aliquot of organic solvent was withdrawn and subsequently injected directly into the HPLC system. Limits of detection for the elected PAHs were between 0.001 and 0.006 g L^–1 with a RSD of 2.6–6.3%.     

固相微萃取-高效液相色谱-荧光检测法测定番茄中的多菌灵和噻菌灵

建立了应用固相微萃取(SPME)-高效液相色谱(HPLC)-荧光检测法测定番茄中多菌灵(MBC)和噻菌灵(TBZ)的分析方法。考察了萃取纤维、萃取时间、萃取温度、解吸时间、解吸液组成、解吸模式、pH值、有机溶剂和离子强度对MBC和TBZ萃取效率的影响,对SPME条件和色谱条件进行了优化。SPME在室温下进行,采用65 μm聚二甲基硅氧烷/二乙烯苯（PDMS/DVB）萃取纤维,萃取溶液中加入100 g/L NaCl,搅拌速度为1100 r/min,萃取时间为50 min。将该法用于番茄中MBC和TBZ的测定,MBC和TBZ的定量线性范围均为0.01~1.0 mg/kg;线性相关系数分别为0.9958和0.9967;检出限分别为0.003和0.001 mg/kg;回收率分别为83.5%和85.6%(n=5),相对标准偏差(RSDs)分别为6.5%和3.8%。该方法操作简单,无需使用有机溶剂,适于分析番茄样品中的MBC和TBZ。     

Determination of less polar heterocyclic amines in meat extracts: fast sample preparation method using solid-phase microextraction prior to high-performance liquid chromatography-fluorescence quantification

A procedure for the determination of less polar heterocyclic amines in meat extracts using solid phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) with fluorescence detection is presented. Analytes were first extracted from the samples using methanol/NaOH by an ultrasound-assisted method, and then concentrated on a Carbowax-templated resin (CW-TPR) SPME fiber. The extraction conditions such as extractant mixture composition, extraction time and extractions number, were optimized and the need of an extract freezing step previous to SPME is discussed. The detection limits under optimal conditions are in the range of 0.28-1.1 ng g⁻¹. The method was applied to the determination of less polar heterocyclic amines in four commercial meat extracts. Recovery values obtained are higher than 60% for the majority of amines.     

Solid-phase microextraction and headspace solid-phase microextraction for the determination of high molecular-weight polycyclic aromatic hydrocarbons in water and soil samples

The feasibility of direct-immersion (DI) solid-phase microextraction (SPME) and headspace (HS) SPME for the determination of high-ring polycyclic aromatic hydrocarbons (PAHs) (4- to 6-ring PAHs) in water and soil samples is studied. Three SPME fibers--100- and 30-microm polydimethylsiloxane (PDMS) and 85-microm polyacrylate (PA) fibers-are compared for the effective extraction of PAHs. Parameters affecting the sorption of PAHs into the fiber such as sampling time, sampling volume, and temperature are also evaluated. The extracted amounts of high-ring PAHs decrease with the decreasing of film thickness, and the 100-microm PDMS has the highest extraction efficiency than 85-microm PA and 30-microm PDMS fibers. Also, the extraction efficiency decreases with the increasing molecular weights of PAHs. Of the 10 high-ring PAHs, only fluoranthene and pyrene can reach equilibrium within 120 min at 25 degrees C for DI-SPME in a water sample. Increasing the temperature to 60 degrees C can increase the sensitivity of PAHs and shorten the equilibrium time. A 0.7- to 25-fold increase in peak area is obtained for DI-SPME when the working temperature is increased to 60 degrees C. For HS-SPME, the extraction efficiency of PAHs decrease when the headspace volume of the sampling system increases. All high-ring PAHs can be detected in a water sample by increasing the temperature to 80 degrees C. However, only 4- and 5-ring PAHs can be quantitated in a CRM soil sample when HS-SPME is used. The addition of a surfactant with high hydrophilic property can effectively enhance the sensitivity of high-ring PAHs. HS-SPME as well as DI-SPME with 100-microm PDMS or 85-microm PA fibers are shown to be suitable methods for analyzing high-ring PAHs in a water sample; however, this technique can only apply in a soil sample for PAHs having up to 5 rings.     

Flocculation-ultrasonic assisted extraction and solid phase clean-up for determination of polycyclic aromatic hydrocarbons in water rich in colloidal particulate with high performance liquid chromatography and ultraviolet-fluorescence detection

In the present work, a simple method of sample preparation for the determination of polycyclic aromatic hydrocarbons (PAHs) in water rich in colloidal particulate was developed. The technique was mainly based on the effect of the flocculation of aluminum sulfate and the adsorption of the flocculation aid florisil. The method contained three steps: flocculation, ultrasonic extraction, and solid-phase extraction cleanup. Major parameters of the procedure were optimized with high performance liquid chromatography (HPLC) separation and ultraviolet-fluorescence detection. When 250 mL model sample containing 16 EPA PAHs was processed, the developed method provided detection limits in the range of 0.02–5 ng/L. Both spiked and non-spiked polluted river water samples rich in suspended particles and organic matters were analyzed. Recoveries and relative standard deviations for the 16 PAHs were in ranges of 86–94% and 3–13% (n = 5), respectively.     

Screening and determination of polycyclic aromatic hydrocarbons in seafoods using QuEChERS-based extraction and high-performance liquid chromatography with fluorescence detection

A rapid, sensitive, and accurate method for the screening and determination of polycyclic aromatic hydrocarbons (PAHs) in edible seafood is described. The method uses quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction and HPLC with fluorescence detection (FLD). The method was developed and validated in response to the massive Deepwater Horizon oil spill in the Gulf of Mexico. Rapid and highly sensitive PAH screening methods are critical tools needed for oil spill response; they help to assess when seafood is safe for harvesting and consumption. Sample preparation involves SPE of edible seafood portions with acetonitrile, followed by the addition of salts to induce water partitioning. After centrifugation, a portion of the acetonitrile layer is filtered prior to analysis via HPLC-FLD. The chromatographic method uses a polymeric C18 stationary phase designed for PAH analysis with gradient elution, and it resolves 15 U.S. Environmental Protection Agency priority parent PAHs in fewer than 20 min. The procedure was validated in three laboratories for the parent PAHs using spike recovery experiments at PAH fortification levels ranging from 25 to 10 000 microg/kg in oysters, shrimp, crab, and finfish, with recoveries ranging from 78 to 99%. Additional validation was conducted for a series of alkylated homologs of naphthalene, dibenzothiophene, and phenanthrene, with recoveries ranging from 87 to 128%. Method accuracy was further assessed based on analysis of National Institute of Standards and Technology Standard Reference Material 1974b. The method provides method detection limits in the sub to low ppb (microg/kg) range, and practical LOQs in the low ppb (microg/kg) range for most of the PAH compounds studied.     

C18-MCM-41新型涂层在固相微萃取中的应用

固相微萃取（SPME）是集采样、萃取和富集于一体的样品前处理技术,该技术于1990年由Pawliszyn提出。由于其不使用有机溶剂,且简便、快速、样品用量少,因而,倍受分析工作者的青睐。