Liquid chromatographic determination of polycyclic aromatic hydrocarbons in fish and shellfish

A simple and accurate analytical method for determination of polycyclic aromatic hydrocarbons (PAHs) in fish and shellfish is presented, which is considered to be useful for routine analyses and for screening purposes. The procedure involves alkaline digestion, extraction with n-hexane, silica gel column chromatography, and liquid chromatographic (LC) determination with fluorometric detection. During development of the analytical method for determination of PAHs, it was found that benzo[a]pyrene, a representative PAH, was decomposed easily by the analytical procedure, and this tendency was investigated for the experimental conditions used. Benzo[a]pyrene was decomposed by the coexistence of alkaline conditions, light, and oxygen; by peroxides in aged ethyl ether; and by oxygen when absorbed on silica gel. Thus, to obtain good recoveries and precise analytical results, these decomposition conditions must be avoided. The following precautions are recommended: protection from light through all analytical steps; addition of Na2S to alkaline digestion mixture as an antioxidant; complete removal of peroxides from ethyl ether just before use; quick column chromatography on silica gel; and prevention of air from contact with adsorbent. When this simple method was applied to fish and shellfish samples, very good recoveries of PAHs from fortified fish samples were obtained, and no serious interferences were observed in fish and shellfish extracts.     

Quantitative determination of polycyclic aromatic hydrocarbons in barbecued meat sausages by gas chromatography coupled to mass spectrometry

A method is described for the analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by the USA EPA in meat sausages grilled under common barbecue practices. Quantification was done by GC-MS using perdeuterated internal standards (IS). Validation was done by spiking the matrix at the 0.5 and 1.0 microg/kg levels. The average of expected values ranged from 60 to 134% (median 84%) at the 0.5 microg/kg level and from 69 to 121% (median 96%) at the 1.0 microg/kg level. The median of the limits of detection and quantification were 0.06 and 0.20 microg/kg, respectively, for a 4-g test portion. The carcinogenic PAHs were below the quantification limit in all products except one lamb sausage. Comparison of estimates when either 1, 5, or 16 perdeuterated PAHs were used as IS showed that the most accurate determination of PAHs required that each compound be quantified against its corresponding perdeuterated analogue.     

Accelerated solvent extraction and gas chromatography/mass spectrometry for determination of polycyclic aromatic hydrocarbons in smoked food samples.

Accelerated solvent extraction (ASE) is a new sample extraction method offering a number of advantages such as low pe -extraction cost, reduced solvent and time consumption, and simplified extraction protocols. In this study, the ASE method was applied to the extraction of polycyclic aromatic hydrocarbons (PAHs) from biological samples. For recovery studies, fish tissues and ground pork were used as sample matrices. Sample aliquots fortified with 16 PAHs were extracted by ASE, and the extracts were treated with sulfuric acid and Florisil, followed by gas chromatography-mass spectrometry analysis. The PAH recoveries by the ASE method were found to be comparable with or better than those by Soxhlet extraction. The extraction and quantitation method was then applied to the determination of PAHs in several smoked meat samples obtained from a local market. Up to 12 PAHs were found to be present at concentrations ranging from 3 to 52 ng/g wet sample.     

A displacement pump procedure to load extracts for automated gel permeation chromatography

Automated gel permeation chromatography (GPC) effectively separates lipids from pesticides in sample extracts that contain fat. Using a large syringe to load sample extracts manually onto GPC models having 5 mL holding loops is awkward, slow, and potentially hazardous. Loading with a small-volume displacement pump, however, is convenient and fast (ca 1 loop every 20 s). And more importantly, the analyst is not exposed to toxic organic vapors because the loading pump and its connecting lines do not leak in the way that a syringe does.     

气相色谱-质谱法同时测定资源化利用畜禽粪污中16种多环芳烃

多环芳烃是畜禽粪污中的重要有机污染物,我国目前尚未建立畜禽粪污中多环芳烃测定的标准方法,制约了畜禽粪污资源安全利用.建立了气相色谱-质谱法同时测定畜禽粪污中16种多环芳烃的新方法.结果表明,16种多环芳烃在0.02～2.00mg/L范围内呈现良好的线性关系,方法检出限在0.005～0.046 mg/kg之间,相对标准偏...     

Optimization of a solid-phase extraction method using centrifugation for the determination of 16 polycyclic aromatic hydrocarbons in water

A fast and reliable method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by solid-phase extraction (SPE) using centrifugation has been developed and optimized. A silica-based C18 cartridge was used; parameters affecting the extraction procedure such as type and volume of the elution solvent, breakthrough volume of the percolated water sample, drying of the sorbent, and evaporation of the elute have been studied. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 1 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under optimal conditions, recoveries for the 16 U.S. EPA PAHs were between 70 and 85% and the relative standard deviation varied between 1 and 14%. Surrogate standard recoveries were similarly between 61 and 94% with a relative standard deviation between 2 and 15%. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.     

Intercomparative study on the determination of polynuclear aromatic hydrocarbons in marine shellfish tissue

Twenty-five laboratories were sent 2 materials, one an acetone powder of lobster digestive gland, the other, the oil which had been extracted during preparation of the powder. Each laboratory was requested to measure the levels of a suite of polycyclic aromatic hydrocarbons in both materials. The response was poor with only 10 laboratories submitting results. Both intra- and interlaboratory precisions were poor; the interlaboratory error was so great as to preclude statistical analysis of the error. Relative standard deviations for oil results determined by liquid chromatography ranged from 39 to 96%.     

Rapid magnetic solid-phase extraction based on magnetic multiwalled carbon nanotubes for the determination of polycyclic aromatic hydrocarbons in edible oils

In this study, magnetic multiwalled carbon nanotubes were fabricated by a simple method and applied to magnetic solid-phase extraction (MSPE) of eight heavy molecular weight polycyclic aromatic hydrocarbons (PAHs) including chrysene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene from edible oil samples. Several parameters affecting the extraction efficiency were investigated, including the type and volume of desorption solvent, extraction and desorption time, washing solution and the amount of sorbent. Under the optimized conditions, a simple and effective method for the determination of PAHs in edible oils was developed by coupling with gas chromatography-mass spectrometry (GC-MS). The whole pretreatment process was rapid, and it can be accomplished within 10 min. The limits of quantitation for the target PAHs were found to be 0.34-2.9 ng/g. The recoveries in oil sample were in the range 87.8-122.3% with the RSDs less than 6.8% (intraday) and 9.6% (interday). This method was successfully applied to the analysis of PAHs in seven kinds of edible oils from local markets.     

Rapid method for determination of leucogentian violet in chicken fat by liquid chromatography with electrochemical detection

The metabolite leucogentian violet (LGV) was found in chicken fat obtained from chickens dosed with gentian violet (GV); however, no residues of the parent compound, GV, and its oxidized metabolites were found. Therefore, a rapid method was developed for the specific determination of LGV in chicken fat. Chicken fat containing LGV is separated from the cellular protein with methylene chloride. LGV is then separated from the fat by partition extraction with an aqueous acid phase in which LGV is protonated, and the fat is discarded with the methylene chloride layer. The aqueous solution is neutralized, LGV is re-extracted into methylene chloride, and the methylene chloride is evaporated. An acetonitrile-water solution containing LGV is filtered before liquid chromatography using a cyano column, an acetate buffer-acetonitrile mobile phase, and an electrochemical detector set at a potential of +1.000 V. Average recoveries of LGV from chicken fat were 83.9% with a coefficient of variation (CV) of 12.9% for the 5 ppb level; 82.8% with a CV of 13.5% for the 10 ppb level; and 77.7% with a CV of 2.56% for the 20 ppb level. Levels of incurred LGV in chicken fat averaged 49.3 ppb with a CV of 2.43%.     

多环芳烃微生物降解机理研究进展

主要阐述了微生物降解PAHs的机理,比较了典型微生物种类芽孢杆菌(Bacillus)和分支杆菌(M.vanbaalenii PYR-1)对同种PAHs菲的代谢过程不同之处,并分析了分支杆菌(M.vanbaalenii PYR-1)对菲和芘的代谢机理,指出微生物氧化降解PAHs主要从其K区和湾区开始,而K区氧化是有毒PAHs降解的主要可能途径,资料显示真菌比细菌对苯并[a]芘的降解能力更强,同时给出了微生物代谢菲、芘和苯并[a]芘的降解图,以便做进一步研究。     

Availability of polycyclic aromatic hydrocarbons in aging soils

Purpose  

The soil contamination by hydrophobic organic contaminants (HOCs), such as polycyclic aromatic hydrocarbons (PAHs), poses great threats to human health and ecological security and attracts worldwide concerns. The total HOC concentrations overestimate its available fraction to the soil biota. Increased understanding of the availabilities of PAHs in soil environment will have considerable benefits for their risk assessment and be very instructive to food safety and remediation strategies in contaminated sites. However, the availability of PAHs in aging soils and particularly the correlations of the availabilities with their forms in soils have yet to be elucidated. In this work, the availabilities of PAHs in aging soils were evaluated using a sequential mild extraction technique.     

Determination of polycyclic aromatic hydrocarbons in commercial liquid smoke flavorings of different compositions by gas chromatography-mass spectrometry

The presence of polycyclic aromatic hydrocarbons (PAHs) in five commercial liquid smoke flavorings, used in the European food industry, was studied. The samples were subjected to an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography-mass spectrometry. Three different procedures for the cleanup were tested. The results revealed the presence of 34 PAHs, some of them with methyl substituents. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Relationships between smoke flavoring compositions and PAH levels were also studied. Three of the samples contained high levels of both total and carcinogenic PAHs. Benzo[a]pyrene was also detected in these three samples, but its concentration did not exceed the 10 microg/kg level fixed by the FAO/WHO. Finally, a relation was found, first between the concentrations of total carcinogenic PAHs and benzo[a]pyrene and also between the concentrations of pyrene and benzo[a]pyrene. The latter ratio reveals that pyrene concentration could be very useful in predicting the level of benzo[a]pyrene and, consequently, in estimating the carcinogenicity arising from the presence of benzo[a]pyrene and other carcinogenic PAHs.     

Microtox技术检测多环芳烃生物毒性的研究

利用Microtox技术检测 5种多环芳烃化合物生物毒性结果表明 ,二甲亚砜配制的测试液中萘、菲及荧蒽均对发光细菌具有一定生物毒性 ,且随浓度的增大而增强 ,相同浓度下毒性菲 >萘 ;测试液中当萘浓度小于其溶解度时即产生 10 0 %的抑光率 ,萘EC50 为 4 .32mg/L ,而菲及荧蒽浓度近其溶解度时所产生的最大抑光率分别为 <5 0 %和15 %左右 ;芘及蒽最大浓度时则对发光细菌无生物毒性显示。表明Microtox技术可有效检测低环化合物萘的生物毒性 ,但对高环化合物 (≥ 3环 )的检测因受其低水溶性的限制而灵敏度降低 ,利用二甲亚砜获取多环芳烃污染物提取液的生物毒性主要与低分子化合物萘及菲有关     

High pressure liquid chromatographic determination of polynuclear aromatic hydrocarbons in oysters.

A high pressure liquid chromatographic (HPLC) procedure is described for determining 13 polynuclear aromatic hydrocarbon (PNA) compounds in oysters at the 2 ppb level. These compounds are extracted from shellfish with acetonitrile and partitioned into petroleum ether; the petroleum ether is removed and the residue is saponified. The aromatic compounds are isolated by passing the saponifeid residue through silica gel and further purified and fractionated by muStyragel gel permeation chromatography. The in-ividual PNAs are then quantitatively determined by using a reverse phase HPLC column coupled to fluorescence, spectrophotometric, and 254 nm absorbance detectors in series. Recoveries from spiked samples generally were greater than 80%.     

Distribution of polycyclic aromatic hydrocarbons in the soil-plant system

The content and composition of the polycyclic aromatic hydrocarbons (PAHs) in the conjugated systems of [arable soil]-[above-ground plant organs] in background (reference) and contaminated regions were studied. The coefficients of the biological uptake of PAHs by plants (K _bPAH) were determined for different PAH concentrations in the soil. Correlations of the PAH accumulation rate in plants with the physicochemical properties of the PAHs—the solubility, hydrophobicity, volatility, and chemical activity (polarizability and ionization potential)—were revealed. The high accuracy, sensitivity, and information value of the standardized parameters K _b were shown (with K _bPAH as an example) for the quantitative study of the accumulation mechanisms of substances by plants compared to the average arithmetic values of their concentrations in the plants.     

Enhanced sorption of polycyclic aromatic hydrocarbons by soil amended with biochar

Purpose  

Polycyclic aromatic hydrocarbon (PAHs) are ubiquitous pollutants in agricultural soils in China. Biochar is the charred product of biomass pyrolysis, which is widely applied to soils to sequestrate atmospheric carbon dioxide and guarantees a long-term benefit for soil fertility. Knowledge about the impacts of various biochars on soil sorption affinity remains obscure. In this study, we evaluated the effects of various biochars on PAHs sorption to biochar-amended agricultural soil.