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101.
Ángel García-Bermejo Manuela Ábalos Jordi Sauló Esteban Abad María José González Belén Gómara 《Analytica chimica acta》2015
This paper reports on the optimisation, characterisation, validation and applicability of gas chromatography coupled to triple quadrupole mass spectrometry in its tandem operation mode (GC-QqQ(MS/MS) for the quantification of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs, dioxins) and dioxin-like polychlorinated biphenyls (DL-PCBs) in environmental and food matrices. MS/MS parameters were selected to achieve the high sensitivity and selectivity required for the analysis of this type of compounds and samples. Good repeatability for areas (RSD = 1–10%, for PCDD/Fs and DL-PCBs) and for ion transition ratios (RSD = 0.3–10%, for PCDD/Fs, and 0.2–15%, for DL-PCBs) and low instrumental limits of detection, 0.07–0.75 pg μL−1 (for dioxins) and 0.05–0.63 pg μL−1 (for DL-PCBs), were obtained. A comparative study of the congener specific determination using both GC-QqQ(MS/MS) and gas chromatography-high resolution mass spectrometry (GC-HRMS) was also performed by analysing several fortified samples and certified reference materials (CRMs) with low (feed and foodstuffs), median (sewage sludge) and high (fly ash) toxic equivalency (TEQ) concentration levels, i.e. 0.60, 1.83, 72.9 and 3609 pg WHO-TEQ(PCDD/Fs) g−1. The agreement between the results obtained for the total TEQs (dioxins) on GC-QqQ(MS/MS) and GC-HRMS in all the investigated samples were within the range of ±4%, and that of DL-PCBs at concentration levels of 0.84 pg WHO-TEQs (DL-PCBs) g−1, in the case of feedstuffs, was 0.11%. Both instrumental methods have similar and comparable linearity, precision and accuracy. The GC-QqQ(MS/MS) sensitivity, lower than that of GC-HRMS, is good enough (iLODs in the down to low pg levels) to detect the normal concentrations of these compounds in food and environmental samples. These results make GC-QqQ(MS/MS) suitable for the quantitative analysis of dioxins and DL-PCBs and a real alternative tool to the reference sector HRMS instruments. 相似文献
102.
Francesca Buiarelli Patrizia Di Filippo Donatella Pomata Carmela Riccardi Martina Bartocci 《International journal of environmental analytical chemistry》2017,97(9):797-818
A novel multi-analyte method for the simultaneous determination of 46 compounds of environmental concern, most of them belonging to the category of persistent organic pollutants, was developed using high-performance liquid chromatography and the results were compared to those obtained by gas chromatography. This study was performed in perspective of a cumulative exposure assessment of substances of health concern in environments where high levels, relatively to airborne particulate matter, can be found. The target compounds included polychlorinated biphenyls, brominated flame–retardants and derivatives of polycyclic aromatic hydrocarbons.The multi-analyte method was evaluated in air particulate matter in terms of reproducibility, linearity, recovery, limits of detection and quantification and matrix effect. The recovery was above 70% for all the analytes, whereas limits of quantification ranged between 23 and 390 pg?m?3 in liquid chromatography and less than ten times in gas chromatography–mass spectrometry.Matrix effect was generally negligible for both the techniques, except the case of the detection of oxygenated derivatives of polycyclic aromatic hydrocarbons by gas chromatography.In order to demonstrate the efficacy and to assess the method performances (accuracy and precision), both the techniques were applied to standard reference materials, and the results were compared, discussing their advantages and disadvantages.The method was finally applied to a real sample of indoor airborne particulate matter with aerodynamic diameter ≤4 μm (PM4).We demonstrated that liquid chromatography was the only technique able to analyse the 46 compounds, including thermally degradable ones, with a single chromatographic run without derivatisation steps. On the other hand, gas chromatography still presents higher sensitivity for the detection of some of the investigated compounds. This study can be considered only explorative and further improvements can be expected with new-generation LC-MS instruments (10–100 times more sensitive). 相似文献
103.
104.
Kubo T Matsumoto H Shiraishi F Nomachi M Nemoto K Hosoya K Kaya K 《Analytica chimica acta》2007,589(2):180-185
We developed novel separation media for hydroxy polychlorinated biphenyls (HO-PCBs) using the molecular imprinting techniques. The results of evaluation for the molecularly imprinted polymers (MIPs) by the liquid chromatography (LC) suggested that MIPs had selective separation ability for certain HO-PCB analogues. The results of the LC evaluations and molecular modeling indicated that the molecular volumes and pKa values of template molecules were related with the retention factor of HO-PCBs. Additionally, according to the detail evaluation toward the selective separation behaviors of MIPs, these HO-PCB analogues have low pKa values dependent on their chemical structures. In other words, the prepared MIPs had selective recognition ability against the analogues, which have an OH group on a phenyl carbon and two chlorine atoms on the both neighboring carbons of the carbon attached with the OH group. Moreover, these analogues may have a potential for thyroid hormone activities so that we attempted to separate these analogues directly from mixtures of HO-PCBs using a prepared MIP. 相似文献
105.
《Journal of separation science》2018,41(3):669-677
A time‐saving method was applied to synthesize methyltrimethoxy‐modified magnetic mesoporous silica with or without p‐toluenesulfonic acid as the catalyst for magnetic solid‐phase extraction. The synthesized materials were systematically characterized. Results demonstrated that methyltrimethoxy modified magnetic mesoporous silica with p‐toluenesulfonic acid as the catalyst has a relatively smaller aperture and extreme hydrophobicity (water contact angle of 135°). To evaluate the feasibility of these prepared materials as effective adsorbents, it was combined with gas chromatography and electron capture detection to determine 26 polychlorinated biphenyls in environmental water. The result revealed that methyltrimethoxy modified magnetic mesoporous silica with p‐toluenesulfonic acid as the catalyst had the best extraction efficiency and recovery. Under the optimized extracted conditions, the proposed method showed good linearity within the concentration range of 5 to 200 ng/L with correlation coefficients of 0.9969 to 0.9999. The limits of detection and quantification based on signal‐to‐noise ratios of 3 and 10 were in the range of 0.16 to 0.91 and 0.52 to 3.0 ng/L, respectively. The polychlorinated biphenyl concentrations in environmental water samples were successfully determined using the developed method. PCB008 and PCB110 were 4.05 and 8.52 ng/L in Red‐Star lake water (Hubei Province, China), respectively. 相似文献
106.
二噁(英)降解方法的研究 总被引:1,自引:0,他引:1
二噁(左口右英)是一类剧毒有机氯化物,已被联合国环境署和世界卫生组织列为持久性有机污染物和一级致癌物质,能够对环境和人类的健康造成重大危害.脱氯降解是降低二噁毒性的有效途径.本文对二噁的光降解、热降解、生物降解和化学降解脱氯作了详尽的评述,比较了各种降解方法的优劣,指出多相催化加氢脱氯降解方法将是今后的发展方向. 相似文献
107.
108.
Yibin Zheng Delei Cai Baifen Huang Jianlong Han Qing Chen Jingshun Zhang Jie Zhang Xiaofeng Wang Haitao Shen 《Journal of separation science》2019,42(3):760-768
We established a method for the separation and detection of nine hydroxylated polychlorinated biphenyls in whole blood and urine samples using ultra high performance liquid chromatography coupled with electrospray negative ionization tandem mass spectrometry. Clean‐up procedures involved a filtration step, and optimization involved a pretreatment step consisting of a simple liquid–liquid extraction using hydrated silica‐gel chromatography (5%). Nine hydroxylated polychlorinated biphenyls were separated on an ultra high performance liquid chromatography HSS T3 column using a gradient elution program of 2 mmol ammonium formate aqueous solution (A) and methanol (B). Recovery ranged from 84.0 to 105.4% for the nine different hydroxylated polychlorinated biphenyls in urine with three spiked levels of 0.1, 1, and 2 ng and from 73.5 to 98.6% for the blood with spiked levels of 0.2, 1, and 2 ng. The relative standard deviations were <8.7% (n = 6), and the limits of detection in urine and whole blood for the nine hydroxylated polychlorinated biphenyls were in the range of 1.5–4 and 20–100 pg/g, respectively. This analytical method may enable the simultaneous detection of various hydroxylated polychlorinated biphenyls from complex tissue matrices. 相似文献
109.
DFT-B3LYP/6-311G** method has been used to optimize molecular geometric structures of 527 polychlorinated fluoranthene(PCFRT) congeners and calculate their thermo-dynamic properties in the ideal gas state,such as heat capacity at constant volume(Cv),entropy(S),standard enthalpy of formation(ΔfH) and standard Gibbs free energy of formation(ΔfG).The relations of Cv,S,ΔfH and ΔfG with the number and position of chlorine atoms have also been explored,from which the relative stability of PCFRT congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation(Δr,fG).It was found that some of the PCFRT isomers are in a nonplanar configuration and there are intramolecular Cl…Cl weak interactions in some of the isomers.With increasing the number of chlorine atoms,the values of ΔfH and ΔfG of the most stable PCFRT isomers decrease initially and then increase.The values of ΔfH and ΔfG of PCFRT congeners with the same number of chlorine atoms show a strong dependence on the positions of chlorine atoms.The relative thermodynamic stability of PCFRT isomers is determined mainly by intramolecular adjacent Cl…Cl nuclear repulsive interaction between Cl atoms at two different six-membered rings.Most PCFRT congeners are easier to form thermodynamically than their parent compound. 相似文献
110.
Quintanilla-López JE Galindo-Iranzo P Gómara B Lebrón-Aguilar R 《Journal of chromatography. A》2010,1217(46):7231-7241
Traditionally, the determination of hydroxylated polychlorinated biphenyls (OH-PCBs) has been carried out by gas chromatography (GC). However, the gas chromatographic behavior and sensitivity of this type of hydroxylated compounds are not always satisfactory, hence a prior derivatization of the OH-PCBs must be performed. Therefore, the development of liquid chromatographic methods should prove to be a very interesting task aimed at dealing with the instrumental determination of OH-PCBs. Taking into account that octadecylsilane stationary phases are not the most adequate for the separation of isobaric compounds, an amide-type column has been tested. For the development of the method, the Response Surface Methodology was used, based on a Box-Wilson Central Composite experimental design. The initial content of methanol in the mobile phase, the gradient time, and the concentration and the pH value of the buffer were chosen as relevant experimental parameters. A global optimum was obtained by selecting the elution time, the sensitivity and the overall resolution as responses to optimize. The developed method for liquid chromatography presented a very good resolution and sensitivity, and a reasonably short analysis time. In addition, a retention study was conducted in order to survey the different interactions that take place in the separation process, showing that hydrogen bonding is the main interaction between OH-PCBs and the amide-type stationary phase. However, a substantial contribution of dispersion forces was present in methanol contents in the mobile phase below 65%. Besides, the pH value of the mobile phase was found to be the most important parameter to control the hydrogen bond forces and therefore, to regulate the OH-PCBs separation. 相似文献