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1.
Summary The retention behaviour of chloro-substituted PAHs on several commercial normal bonded phase HPLC columns has been investigated. Chloro-substitution was shown to generally decrease the retention on stationary phases like amino-, diol- and nitrophenylpropyl-modified silica. Dimethylaminosilica exhibited more complex retention characteristics towards chloro-substituted PAHs. On this stationary phase, the position of the chlorine substituents on the aromatic solute seemed to be of greater importance for retention than on the amino-, nitro- and diolsilica. For some chloro-PAHs, the retention was shown to increase with the number of chloro-substitutions, probably due to the large affinity of the electron-rich nitrogen in the stationary phase for the electron deficient -system of the chloro-PAHs. Chloro-substituted PAHs were strongly retarded on the electron donating 2-(1-pyrenyl)-ethylsilica (PYE) stationary phase. However, the molecular shape of the chloro-derivatives had a large influence on retention, which was considerably decreased for some nonplanar chloro-derivatives of chrysene and benz(a)anthracene. A two-dimensional back-flush HPLC method, consisting of a combination of a nitrophenylsilica column and a PYE column of matched lengths, was shown to be useful for clean-up of chloro-substituted PAHs in environmental samples. 相似文献
2.
Summary Retention characteristics of series of polymethyl and mono-n-alkyl derivatives of benzene and pyrene, and also of parent polycyclic
aromatic hydrocarbons (PAH), were studied using silica and aminopropyl- and cyanopropyl-modified silica. Differences in the
selectivities for the studied compound groups were found between the three phases. Deviations from linear behaviour in plots
of log (k′)vs. carbon number were observed for the methyl series. These are explained in terms of differences in π-electron delocalisation
within the aromatic ring systems. Further, the effect of methyl substitution on selectivity decreased with an increasing number
of aromatic rings. Results were obtained which indicated that the primary adsorption site in a cyano column used in normal
phase mode, at least for PAH molecules, is the cyano group. 相似文献
3.
A. Catabay C. Okumura K. Jinno J. J. Pesek E. Williamsen J. C. Fetzer W. R. Biggs 《Chromatographia》1998,47(1-2):13-20
Summary The retention behavior of large polycyclic aromatic hydrocarbons (PAH) in reversed-phase microcolumn liquid chromatography
has been found to depend primarily on the inherent planarity of the molecules, the degree of orderliness of the bonded phase,
and the concentration of solvent. The planarity recognition capability of cholesteryl 10-undecenoate bonded phase for large
PAH is comparable with that of monomeric ODS phases. During solvation, however, the phase characteristics seemed to suggest
a fairly rigid structure (an ordered phase), i.e. increased selectivity for non-planar molecules which approaches that of
polymeric ODS rather than that of other phases with similarly bulky groups, e.g. naphthylethyl and pyrenylethyl bonded phases. 相似文献
4.
Summary High performace liquid chromatography (HPLC) was used to separate the large polycyclic aromatic hydrocarbons in a diesel particulate
extract. Identification of individual peaks was made using a photodiode array UV/visible detector to collect their absorbance
spectra. Comparisons between standard compounds and the peaks were made using both retention times and spectra. Compounds
of up to 10 rings were identified. 相似文献
5.
Summary In this paper the evaluation of polycyclic aromatic hydrocarbons (PAHs) in gasoline is described. A procedure involving a
double extraction of samples with N-methylpirrolidone-water-phosphoric acid and with cyclohexane has been used followed by
HPLC-DAD and GC-MS. The results obtained show that all gasoline samples contain PAHs with two to six rings and no substantial
difference was noticed between leaded and unleaded gasoline. The benzo(a)-pyrene content ranged between 1.0–2.0 mg L−1, a comparatively high concentration for a dangerous compound. 相似文献
6.
Summary The relationship between the logarithmic capacity factor measured in reversed-phase liquid chromatography and the operating conditions including the mobile phase composition and the column temperature is investigated. The strategy described herein can offer the possibility to predict the retention of polycyclic aromatic hydrocarbons without any experiments and standard materials, by utilizing equations describing the relationships between retention, temperature, mobile phase composition and physicochemical properties of the solutes previously stored in the program of the microcomputer-assisted retention prediction system.This concept is one of the most promising techniques for the optimization of the separation conditions in reversed-phase liquid chromatography. 相似文献
7.
Gy. Kiss Z. Varga-Puchony A. Gelencsér Z. Krivácsy Á. Molnár J. Hlavay 《Chromatographia》1998,48(1-2):149-153
Summary Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in water and sediment samples at 15 sites in Lake
Balaton during three sampling campaigns in 1996. PAHs were concentrated from water samples by solid phase extraction. Sediment
samples were extracted with acetone in an ultrasonic bath then cleaned by solid phase extraction. The total concentration
of PAHs ranged from 30–360 ng g−1 and from 170–720 ng L−1 in sediment and water samples, respectively. Spatial and temporal variations of the concentration of PAHs were also investigated.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997. 相似文献
8.
Retention behavior of polycyclic aromatic hydrocarbons (PAHs) on an acridine derivative stationary phase was examined in microcolumn liquid chromatography. 3,6-Bis(dimethylamino)-10-dodecylacridinium was electrostatically introduced into a cation-exchanger, and its selectivity was compared with that of octadecylsilyl-bonded silica gel. The former stationary phase provided smaller retention for non-planar PAHs than that achieved by the latter stationary phase. The results suggest that interaction between PAHs and the acridinyl ring dominates the retention of PAHs, and preferential retention of planar PAHs is attributed to the fact that they have more chance to interact with the acridinyl ring of the stationary phase than non-planar PAHs. 相似文献
9.
Summary Elution strengths of 11 common HPLC solvents on a polymeric C18 phase were compared using a marker set of polycyclic aromatic hydrocarbons. Naphthalene, pyrene, benzo[ghi]perylene, and three larger naphthologues of 8, 10, and 12 rings (constituting a naphthalene zigzag series) were chosen because they span the solvent strength range up to and including the strongest solvents, tetrahydrofuran (THF) and chlorobenzene. Four pairs of similarly shaped isomers were used to probe solvent selectivity. With the exception of THF, HPLC solvent strength correlated with observed red shifts of fluorescence band maxima in each solvent. For THF, the pure solvent and blended mixtures behaved quite differently. 相似文献
10.
Herman Maloko Loussala Juanjuan Feng Sen Han Min Sun Xiangping Ji Chunying Li Jing Fan Meishan Pei 《Journal of separation science》2020,43(16):3275-3284
A mesoporous silica was functionalized by carbon nanotubes to enhance the extraction performance. The mesoporous material was coated on stainless steel wires, and three wires were inserted inside of a polyetheretherketone tube for in‐tube solid‐phase microextraction. The tube was coupled to high‐performance liquid chromatography with diode array detection to obtain online analytical system, then its extraction performance was evaluated using eight polycyclic aromatic hydrocarbons as the targets. In order to good sensitivity and accuracy, four conditions were optimized such as sampling volume, sampling rate, methanol content in the sample, and desorption time. Under the optimum conditions, an online analytical method was established and exhibited low limits of detection from 0.005 to 0.050 µg/L, wide linear range of 0.016‐20.00 µg/L with acceptable correlation coefficients in 0.9921‐0.9999, as well as large enrichment factors in the range of 311‐2412. The method was successfully applied to determine trace polycyclic aromatic hydrocarbons in some real water samples including, two kinds of bottled water, tap water, and river water, a few polycyclic aromatic hydrocarbons were detected but none quantified in these samples. 相似文献
11.
12.
A. Matthiessen 《Chromatographia》1997,45(1):190-194
Summary The recorveries of volatile polycyclic aromatic hydrocarbons in HPLC analysis may be enhanced if a long-chain alcohol, e.g.
1-hexanol or 1-octanol, is used as keeper in the solvent-evaporation step. Even under the harsh conditions of the vacuum-concentrator
centrifuge, recoveries of more than 90% were achieved for 14 of the 15 PAH tested. The use of liquid-liquid extraction (LLE)
eliminates the problem of adsorption of highly condensed aromatics by the wall of the sampling bottle. The combination of
LLE with vacuum-controlled rotary evaporation and use of a keeper yielded overall recoveries between 50 and 130%, for most
substances close to 100%, from tap water spiked with trace concentrations.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
13.
Summary The retention prediction system assisted by a micro-computer coupled with an UV multichannel detector has been investigated in the separation of polycyclic aromatic hydrocarbons. The method offered very precise identification of components in NBS-SRM-1647 sample without any standard reference substances. It has been proven that the system makes very precise, non-pollutive and convenient environmental analysis possible. 相似文献
14.
Summary Both the separation of polycyclic aromatic hydrocarbons (PAH's) on tailor made HPLC phases, and their chromatographic enrichment
and quantitative determination are of great interest. Because of the generally low concentrations of PAH's in the environment,
and the low limiting values in German legislation for drinking water, methods for selective enrichment and sensitive detection
are indispensable. On account of their relatively high amounts in soil, the determination of PAH's is valuable for the assessment
of the potential danger to ground water by waste materials. These requirements can be fulfilled by used of solid phase extraction
on enrichment columns, and fluorescence or UV/VIS diode array detection.
For the detection of PAH's in the picogram range, the wavelengths for excitation and emission were time programmed over the
chromatogram. With this feature, it is possible to detect all the individual compounds at the highest sensitivity, over the
entire analysis. 相似文献
15.
Summary A simple and efficient method of separating a 20-component PAH-mixture (RSM 1647 standard mixture +benzene, toluene, perylene and coronene) by RP-HPLC is described. Separation was by using two Superspher-100 RP-18 cartridges thermostatted at different temperatures under isocratic conditions with water-acetonitrile eluent. The analysis time with complete resolution of all components can be reduced to 15 min. 相似文献
16.
17.
Analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples: a critical review of gas chromatographic (GC) methods 总被引:1,自引:0,他引:1
Polycyclic aromatic hydrocarbons (PAHs) are frequently measured in the atmosphere for air quality assessment, in biological
tissues for health-effects monitoring, in sediments and mollusks for environmental monitoring, and in foodstuffs for safety
reasons. In contemporary analysis of these complex matrices, gas chromatography (GC), rather than liquid chromatography (LC),
is often the preferred approach for separation, identification, and quantification of PAHs, largely because GC generally affords
greater selectivity, resolution, and sensitivity than LC. This article reviews modern-day GC and state-of-the-art GC techniques
used for the determination of PAHs in environmental samples. Standard test methods are discussed. GC separations of PAHs on
a variety of capillary columns are examined, and the properties and uses of selected mass spectrometric (MS) techniques are
presented. PAH literature on GC with MS techniques, including chemical ionization, ion-trap MS, time-of-flight MS (TOF-MS),
and isotope-ratio mass spectrometry (IRMS), is reviewed. Enhancements to GC, for example large-volume injection, thermal desorption,
fast GC, and coupling of GC to LC, are also discussed with regard to the determination of PAHs in an effort to demonstrate
the vigor and robustness GC continues to achieve in the analytical sciences. 相似文献
18.
Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid‐phase extraction coupled with gas chromatography and mass spectrometry 下载免费PDF全文
Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid‐phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid‐phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0–1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015–0.591 and 0.045–1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1‐monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m?3. 9,10‐Dichloroanthracene and 1‐monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water. 相似文献
19.
Yoshihiro Saito Hatsuichi Ohta Hiroshi Terasaki Yoshiyuki Katoh Hideo Nagashima Kiyokatsu Jinno Kenji Itoh 《Journal of separation science》1995,18(9):569-572
A chemically bonded C60 silica phase was synthesized as a stationary phase for liquid chromatography (LC) and its retention behavior evaluated for various polycyclic aromatic hydrocarbons (PAHs) using microcolumn LC. The results indicate that the C60 bonded phase offers selectivity different from that of octadecylsilica (ODS) bonded phases in the separation of isomeric PAHs. With the C60 phase, PAH molecules having a partial structure similar to that of the C60 molecule, e.g. triphenylene and perylene, were retained longer than with ordinary ODS stationary phases. The results also show that good correlation exists between the retention data with this C60 bonded phase and with C60 itself as the stationary phase. 相似文献