Determination of polycyclic aromatic hydrocarbons by high-performance liquid chromatography-particle beam-mass spectrometry

In this article, we report a high-performance liquid chromatography-particle beam-mass spectrometric (HPLC-PB-MS) method for the determination of polycyclic aromatic hydrocarbons (PAHs). The PB interface consists of a concentric ultrasonic nebulizer with temperature-controlled desolvation chamber and a three-stage momentum separator. The HPLCPB-MS method showed greater sensitivity for PAHs with molecular weights above 178 than for those PAHs with molecular weights below 178. The percent relative standard deviations for the determination of 0.5 ng chrysene, 1.0 ng dibenzo[a,h]anthracene, 1.0 ng benzo[g,h,i]perylene, and 2.5 ng coronene were 20%, 2.5%, 13.7%, and 6%, respectively. The detection limits at signal/noise = 3 were 0.2 ng for chrysene, 1.0 ng for dibenzo[a,h]anthracene, 0.5 ng for benzo[g,h,i]perylene, and 1.5 ng for coronene.     

Characterization of chromium-carbene complexes by high-performance liquid chromatography-mass spectrometry with particle beam interface

High-performance liquid chromatography (HPLC) coupled with mass spectrometric (MS) detection was used to separate and characterize a series of chromium -aminocarbene and alkoxycarbene complexes of the Fischer type, some of which were synthesized as new compounds. Chromium-carbene complexes are known to have interesting photochemical properties. The separation of all the compounds examined was performed under normal-phase conditions and a particle beam LC-MS interface was used. The acquisition of positive-ion and negative-ion chemical ionization mass spectra of the eluates was performed. The use of the LC-PB-MS system demonstrated the potential role of this technique in the elucidation of the structure of polar organometallic compounds, such as the carbene complexes of chromium examined.     

Application of liquid chromatography-particle beam mass spectrometry and gas chromatography-mass spectrometry for the identification of metabolites of polycyclic aromatic hydrocarbons

Chromatographia - Two liquid chromatography-particle beam mass spectrometry (LC-PBMS) systems have been used for analysis of polycyclic aromatic hydrocarbon metabolites in water samples from a...     

Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction-gas chromatography-mass spectrometry

A solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples has been developed, based on the sorption of target analytes on a selectively sorptive fibre and subsequent desorption of analytes directly into GC-MS. The influence of various parameters on PAH extraction efficiency by SPME was thoroughly studied. Results show that the fibre exposure time and the use of agitation during exposure are critical in enhancing SPME performance. The presence of colloidal organic matter (as simulated by humic acid) in water samples is shown to significantly reduce the extraction efficiency, suggesting that SPME primarily extracts the truly dissolved compounds. This offers the significant advantage of allowing the differentiation between freely available dissolved compounds and those associated with humic material and potentially biologically unavailable. The method showed good linearity up to 10 μg/l. The reproducibility of the measurements expressed as relative standard deviation (R.S.D.) was generally <20%. The method developed was then applied to extract PAHs from sediment porewater samples collected from the Mersey Estuary, UK. Total PAH concentrations in porewater were found to vary between 95 and 742 ng/l with two to four ring PAHs predominating. Results suggest that SPME has the potential to accurately determine the dissolved concentrations of PAHs in sediment porewater.     

Characterisation of polycyclic aromatic hydrocarbons in atmospheric aerosols by gas chromatography-mass spectrometry

An accurate and reliable method for determining polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosols is described. This optimised gas chromatography-mass spectrometry (GC-MS) method permits a wide range of concentrations to be analysed without the influence of interferences.Pre-treatment comparison of four kinds of aerosol collector filters determined that quartz and glass fibre filters were the most suitable. Solvents like cyclohexane, toluene, acetonitrile and dichloromethane were evaluated for their PAH-extraction capacity. Ultrasonic extraction using CH₂Cl₂ was selected because it is rapid and easy; moreover, this solvent increases the sample-throughput capacity.PAH compounds were quantitatively collected and ultrasonically extracted twice using 15 mL of CH₂Cl₂ for 15 min for each replicate. Rotavapor concentration, fractionation and dissolution were also optimised.A certified standard mixture (16 EPA PAHs), a deuterated compound and precision recovery assays were used for validating the proposed methodology. Adequate analytical parameters were obtained. Detection limits were (1.6-26.3) × 10⁻⁵ ng and quantification limits were (5.2-87.6) × 10⁻⁵ ng.Analysis of the environmental samples detected 4-10 EPA list PAH compounds. In addition, 2-11 tentative compounds were found, and their molecular structures were described for the first time.Our study of both Youden method and the standard addition method has shown that the proposed determination of PAHs in environmental samples is free of systematic errors.In conclusion, this unbiased methodology improves the identification and quantification of PAH compounds. High sensitivity as well as acceptable detection and quantification limits were obtained for the environmental applications.     

气相色谱-质谱法测定热塑性弹性体中的多环芳烃

建立了一种简单、准确的测定热塑性弹性体中16种多环芳烃(PAHs)的气相色谱-质谱(GC-MS)方法。考察了样品制备、萃取溶剂、萃取方法、时间以及温度对厂家制备的阳性热塑性弹性体样品中PAHs提取效率的影响,确定了萃取条件和方法。样品经甲苯超声萃取、浓缩后用环己烷溶解、二甲亚砜液液萃取净化后采用GC-MS进行分析,内标法定量。通过对不同材质阳性热塑性弹性体样品的加标回收、精密度试验等对建立的方法进行评价,16种PAHs的平均回收率为70%～117%,精密度为0.2%～10.8%。该方法适合于热塑性弹性体中PAHs的测定。     

Analysis of coumarins by micro high-performance liquid chromatography-mass spectrometry with a particle beam interface

Coumarins are a large group of compounds that are naturally present in plant tissues and that exhibit a wide range of pharmacological properties. Analytical methods based on chromatographic techniques and conventional detectors are inadequate to accurately analyze coumarins in complex matrices such as plant extracts. In this article a new method based on a modified particle beam liquid chromatography-mass spectrometry interface is described. The method allows specific and accurate determination of several coumarins in biological matrices. An application regarding the analysis of 18 coumarins in the extract of Smyrnium perfoliatum L. is also reported.     

气相色谱质谱法测定化妆品中9种多环芳烃

建立了气相色谱质谱法测定化妆品中9种多环芳烃的分析方法。化妆品中的萘、苯并[a]蒽、、苯并[b]荧蒽、苯并[j]荧蒽、苯并[k]荧蒽、苯并[e]芘、苯并[a]芘、二苯并[a,h]蒽等9种多环芳烃用甲醇超声提取后,用环己烷液-液萃取后浓缩,经硅胶-中性氧化铝柱净化后,采用气相色谱-质谱测定。多环芳烃浓度在0.05～2 mg/L范围内,质量浓度与其峰面积呈良好的线性关系。在低、中、高3个添加水平下,9种多环芳烃化合物的平均回收率为81.6%～100.2%,相对标准偏差为1.3%～5.8%。方法可用于化妆品中多环芳烃的检测。     

Static pressurised liquid extraction of nitrated polycyclic aromatic hydrocarbons from soils with on-line filtration-preconcentration prior to gas chromatography-mass spectrometry detection

Nitrated polycyclic aromatic hydrocarbons have been extracted from both spiked and natural contaminated soils by using static pressurised liquid extraction. The variables governing the extraction (namely, pressure, extraction time, temperature and number of static extraction cycles) have been optimised using the experimental design methodology. A laboratory-made pressurised liquid extractor has been used allowing its coupling to a filtration-preconcentration system through a flow injection interface, thus providing a partially automated approach. Gas chromatography with MS-MS ion preparation mode has been used for individual separation-identification/quantification providing both high selectivity (no interferences were observed) and sensitivity (detection limits of low pg). The comparison of the proposed approach with the reference EPA Method 3540 has shown that both methods provide similar efficiencies but with dramatic saving of time by the former (30 min vs. 24 h). The use of water as leaching agent avoids the use of organic solvents, thus providing an environmentally friendly method.     

Determination of polycyclic aromatic hydrocarbons in Diesel soot by high-performance liquid chromatography

Summary The described identification and determination of polycyclic aromatic hydrocarbons (PAH) in Diesel soot is based on a class-fractionation using an open Al₂O₃-column and a following separation on a reversed-phase HPLC-column with post-chromatographic derivatization. The optimized analysis has been applied to the determination of PAH in soots from different engines such as locomotives and motor vehicles by variation of the fuel additives and different Diesel/water emulsions. The results obtained by locomotives show that a special Diesel/water emulsion emits a minor amount of mutagenic and cancerogenic polycyclic aromatic hydrocarbons, whereas the emission of the comparatively harmless compounds like phenanthrene and benzo(h)quinoline increases.     

Determination of polycyclic aromatic hydrocarbons in waters by ultrasound-assisted emulsification-microextraction and gas chromatography-mass spectrometry

An ultrasound-assisted emulsification-microextraction (USAEME) procedure was developed for the extraction of US EPA 16 polycyclic aromatic hydrocarbons (PAHs) in 10 mL of water samples, with subsequent determination by gas chromatography-mass spectrometry (GC-MS). After determination of the most suitable solvent and solvent volume, several other parameters (i.e., extraction time, centrifugation time and ionic strength of the sample) were optimized using a 2³ factorial experimental design. Limits of detection ranged from 0.001 to 0.036 μg L⁻¹. The developed procedure was applied to fortified distilled water with different fortification levels (0.5, 2 and 5 μg L⁻¹). Recoveries were over 92% and relative standard deviations of the recoveries were below 8%. The efficiency of the USAEME was compared with traditional liquid-liquid extraction (LLE) and solid-phase extraction on real water samples (i.e., tap water, well water and surface (lake) water as well as domestic and industrial wastewaters). The USAEME showed comparable efficiencies especially with LLE. The developed USAEME was demonstrated to be robust, viable, simple, rapid and easy to use for the determination of PAHs in water samples by GC-MS.     

Modern state of high-performance liquid chromatography of polycyclic aromatic hydrocarbons

The review is devoted to the recent studies in the field of high-performance liquid chromatography (HPLC) of polycyclic aromatic hydrocarbons (PAHs). The existing certified techniques, developments of synthesis of new sorbents for separating PAH isomers, and study of the retention mechanism are discussed. It also considers the modern methods of extraction and concentration of PAHs, mainly from environmental objects, which are compatible with subsequent identification by HPLC, as well as the necessity of analytical control of contamination of the environment, food sources, and food supplies with PAHs.     

Pressurised liquid extraction of polycyclic aromatic hydrocarbons from contaminated soils

The reliability and efficiency of the pressurised liquid extraction technique (PLE) for extracting polycyclic aromatic hydrocarbons (PAHs) from contaminated soil has been investigated. Experimental design was used to study the influence of seven extraction variables (sample load, solvents used, solvent ratios, pressure, temperature, extraction time, and rinse volume). The results show that large sample loads in combination with small solvent volumes may result in low extraction efficiency. They also indicate that the recovery of low-molecular-mass PAHs is reduced by low extraction temperatures. The exact settings of the other variables are, however, less significant for the extraction efficiency. Repeated extractions at optimised settings of the tested variables show that PLE is an exhaustive extraction technique that generally results in high yields. In addition, extraction of a certified reference material (CRM 103-100) revealed that the method is both accurate and precise. Another finding was that adding the internal standard on top of the soil in the extraction cell causes considerable over-estimation of the concentrations when large samples are extracted with small solvent volumes. This is because the PLE-cell resembles a chromatographic column, so compounds added to the top of the soil layer have a longer distance to travel through the soil compared to the average distance of the native compounds, which are distributed evenly throughout the column. We therefore recommend that the internal standard should be added to the extract immediately after the extraction or, alternatively, carefully mixed with the sample prior to extraction.     

二级热脱附-气相色谱-质谱联用测定大气可吸入颗粒物中的16种多环芳烃

建立了二级热脱附-气相色谱-质谱联用技术测定大气可吸入颗粒物PM10中16种多环芳烃的分析方法。对二级热脱附和色谱-质谱条件进行了优化。实验结果表明,方法的检出限为0.14～0.42 ng/m3,平均加标回收率为52.7%～97.9%,相对标准偏差(RSD)为8.0%～18.4%。与传统方法相比,该方法的样品前处理时间短、有机溶剂的使用量少,是对人体及环境友善的检测技术。该方法已应用于32份实际大气颗粒物样品的分析。     

Determination of aromatic and polycyclic aromatic hydrocarbons in gasoline using programmed temperature vaporization-gas chromatography-mass spectrometry

A sensitive method is presented for the fast analysis of three aromatic and six polycyclic aromatic hydrocarbons (biphenyl, 3-methylbiphenyl, 4-methylbiphenyl, fluorene, phenanthrene, fluoranthene, pyrene, 1,2-benz(a)anthracene and chrysene) in gasoline samples. The applicability of a GC device equipped with a programmable temperature vaporizer (PTV) and an MS detector is explored. Additionally, a modular accelerated column heater (MACH) was used to control the temperature of the capillary gas chromatography column. This module can be heated and cooled very rapidly, making total analysis cycle times very short. The proposed method does not require any previous analyte extraction and preconcentration step, as in most methods described to date. Sample preparation is reduced to simply diluting the gasoline samples in methanol. This reduces the experimental errors associated with this step of the analytical process. By using sampling injection in the solvent vent mode, and through choice of a suitable temperature, the lightest major components of the gasoline were removed. Moreover, use of a liner packed with Tenax-TA allowed the compounds of interest to be retained during the process. This working strategy could be extended to other groups of compounds through the choice of different venting temperatures. In this way, a large part of the gasoline components are eliminated, the life of the liner is prolonged, and it is possible to inject sample volumes that will not saturate the chromatographic column. The limits of detection ranged from 0.61 microg/L (pyrene) to 6.1 microg/L (biphenyl), and precision (measured as the relative standard deviation) was equal to or lower than 7.3%. The method was applied to the determination of analytes in gasoline samples and the results obtained can be considered highly satisfactory.     

Isotope dilution determination of polycyclic aromatic hydrocarbons in olive pomace oil by gas chromatography-mass spectrometry

A gas chromatographic (GC) method with mass spectrometry detection (MS) for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in olive pomace oil has been developed. The oil was diluted with n-pentane and extracted by liquid-liquid partition with dimethyl sulphoxide (DMSO). After water addition and back-extraction with cyclohexane, a thin-layer chromatography on silica gel was performed as a further purification step. The PAHs spot was scraped off from the plate and the final extract was concentrated and analysed by GC-MS in full scan mode. The eight PAHs under investigation were determined in the presence of the corresponding labelled compounds added as internal standards to the sample at the beginning of the analytical process. The identified PAHs were then quantified by the isotope dilution methodology assuring the compensation of the concentration of each analyte for any variation in the sample preparation. The method precision was satisfactory with relative standard deviation (R.S.D.) values in the range 3.6-12.7% for all PAHs. The average recovery rates ranged from 69.0 to 97.5%. Accuracy was also calculated for benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene by analysing a certified reference material (CRM 458, coconut oil) with adequate results. All response curves exhibited a linear fit from 0.1 to 10 microg ml(-1) and the determination coefficients R2 were better than 0.9942. The limits of detection (0.1-0.4 microg kg(-1)) were acceptable when compared with the maximum permitted limit of 2 microg kg(-1) for each of the eight considered PAHs and 5 microg kg(-1) for the sum of the eight PAHs established by the Italian legislation. Measurement uncertainty was finally calculated identifying and quantifying the uncertainty components of the analytical process. The relative expanded uncertainties (Uc), expressed as percent values were in the range 8.5-11.4% thus appropriate for residues quantification in the range of concentrations considered in the present study.     

Ultrasonication extraction coupled with magnetic solid-phase clean-up for the determination of polycyclic aromatic hydrocarbons in soils by high-performance liquid chromatography

C18-functionalized magnetic microspheres synthesized in a three-stage system and characterized by Fourier transform infrared (FTIR) spectroscopy and SEM were applied for clean-up and enrichment of polycyclic aromatic hydrocarbons (PAHs) in soil samples combined with ultrasonication extraction. Magnetic solid-phase extraction (MSPE) parameters, such as elution solvents, amounts of sorbents, enrichment time and organic modifier, were optimized together with ultrasonication time and extraction solvents. Under the optimal conditions, the developed method provided spiked recoveries of 63.2-92.8% with RSDs of less than 6.4% and limits of detection were 0.5-1.0 ng/g. This new method provides several advantages, such as high extraction efficiency, convenient extraction procedure and short analysis times. Finally, the method was successfully applied to the determination of polycyclic aromatic hydrocarbons in soil samples.     

Identification of aromatic moieties and mycosamine in antifungal heptaenes with high-performance liquid chromatography, high-performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

A high-performance liquid chromatographic (HPLC) method for the determination of the aromaticity of heptaene polyene antibiotics has been developed. The released aromatic moiety of the heptaene polyenes aureofungin, candicidin, candimycin, hamycin and trichomycin was assayed after alkaline hydrolysis. The presence of p-aminoacetophenone (PAAP) and N-methyl-p-aminoacetophenone (N-methyl-PAAP) in the hydrolysates was determined by HPLC, HPLC-mass spectrometry (HPLC-MS) and gas chromatography-MS (GC-MS). Candicidin and hamycin contained only the PAAP residue; aureofungin contained both PAAP and N-methyl-PAAP. Trichomycin contained PAAP and also some unknown component of molecular weight 179. The aromatic nature of the individual components of the heptaene complex was demonstrated using radioactivity flow detection for the determination of the incorporation of [14C]-p-aminobenzoic acid to individual candicidin components. Ammonia chemical ionization MS was successfully used for the GC-MS identification of the acetylated mycosamine moiety of heptaenes.     

Determination of polycyclic aromatic hydrocarbons in sediment using solid-phase microextraction with gas chromatography-mass spectrometry

Manual solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) is applied for the determination of polycyclic aromatic hydrocarbons (PAHs) from natural matrix through a distilled water medium. Seven of the 16 PAH standards (naphthalene, acenaphthene, fluorene, anthracene, fluoranthene, pyrene, benzo[a]anthracene) are spiked on a marine muddy sediment. The samples, containing PAHs in the range of 10-20 ppm, are then aged at room temperature more than 10 days before analysis. The influence of the matrix, SPME adsorption time, pH, salt content, and SPME adsorption temperature are investigated. The reproducibility of the technique is less than 13% (RDS) for the first 6 considered PAHs and 28% (RDS) for benzo(a)anthracene with a fiber containing a 100-micron poly dimethylsiloxane coating. Linearity extended in the range of 5-50 picograms for PAHs direct injection, 5-70 picograms for PAHs in water, and 1-170 picograms for PAHs in sediment. The detection limit is estimated less than 1 microgram/kg of dry sample for the first 6 considered PAHs in sediment and 1.5 micrograms/kg of dry sample for benzo(a)anthracene using the selected ion monitoring mode in GC-MS. The recoveries of the considered PAHs are evaluated.