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Silica monoliths were fabricated inside fused-silica capillaries. Then the monolithic columns were coated with membrane-like zirconia. The zirconia-coated silica monoliths exhibited different EOF behavior comparing with that of bare silica monoliths. The magnitude and direction could be manipulated by changing the running buffers. Due to the amphoteric characteristic of zirconia, the silica monoliths...
The use of surface-enhanced Raman spectroscopy (SERS) for trace determination of polycyclic aromatic hydrocarbons (PAHs) is described. This paper focuses on the development of SERS-active substrates that are specific for the characterization and spectroscopic study of PAHs. The SERS-active substrates are based on thin gold films evaporated on a glass surface previously treated with a mercaptoalkylsilane...
Two methods were developed for the simultaneous quantitative monitoring of photodegradation process of dibenz[a,h]anthracene (DibA), benz[a]anthracene (BaA), benz[a]pyrene (BaP) and benz[k]fluorantene (BkF) using excitation–emission fluorescence spectroscopy. Parallel factor analysis (PARAFAC) and multivariate curve resolution-alternating least squares (MCR-ALS) were satisfactory applied to the data...
The effect of axial temperature gradient (ATG) along a microcolumn on the separation performance at both isocratic and gradient elution mode was investigated. A thermostat system was designed to form an ATG along the packed column. Polycyclic aromatic hydrocarbons (PAHs) were separated on a 0.53mm ×150mm i.d. 5μm C 18 microcolumn, with water and acetonitrile as mobile phase. The separation...
Naphthalene, biphenyl, acenaphtene, anthracene and pyrene were extracted from water samples using inner walls of polytetrafluoroethylene capillary. Optimum conditions for sorption, desorption and heart-cutting of the analyte zone were found. Combined on-line solid-phase extraction and HPLC method for determination of these compounds was proposed. Limits of detection were: (μgL −1 ): 0.4 (naphthalene),...
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...
A method using on-line enrichment and fast high-performance liquid chromatography (HPLC) with fluorescence detection has been developed and validated for the determination of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate samples. The evaporation step for sample preparation can be eliminated since this system allows the injection of 1000μL of sample solution. PAH recoveries were...
First-order derivative of 15 points smoothed chromatograms of mixtures of benzo(b)fluoranthene (BbF) and benzo(k)fluoranthene (BkF) for the m/z 252 ion obtained using two microscans has been proposed as a simple alternative to the resolution of overlapped chromatographic peaks of these two compounds which have identical mass spectra. The procedure provides limits of detection of 12 and 29ngg −1...
This paper reports the multivariate optimization of a liquid–liquid extraction procedure for the determination of 15 EPA-polycyclic aromatic hydrocarbons (PAHs) by high-performance liquid chromatography with fluorescence detection. A Doehlert design was used to find optimum conditions for the procedure through Response Surface Methodology. Three variables (total volume of hexane, number of extraction...
Monodisperse magnetic C 18 microspheres were prepared based on the three-step reactions of solvothermal reduction, silanization and alkylation. The microspheres are of uniform sizes in the range of 200–260nm. The structure of synthesized magnetic C 18 microspheres was studied by transmission electron microscopy, scanning electron microscopy, X-ray diffraction patterns, element analysis...
The gas chromatography–mass spectrometry (GC–MS) system is presently routinely used in environmental analysis of trace organic compounds. With the use of a MS-detector, stable isotope-labelled materials’ analogous of the native analyte are convenient internal standard. They can be used for tracing and compensating analytes’ losses during the particular stages of analytical procedure, such as cleaning...
Quantification of polycyclic aromatic hydrocarbons (PAHs) in smoked fish products often requires multiple clean-up steps to remove fat and other compounds that may interfere with the chemical analysis. We present a novel pressurized liquid extraction (PLE) method that integrates exhaustive extraction with fat retention in one single analytical step. The PLE parameters: type of fat retainer, flush...
Organic pollutants include a very wide variety of chemical compounds with different structures, properties, functions and origins, which may produce diverse damages to the ecosystem and the human beings. This review presents the recent progress on the use of chemometrics to evaluate the occurrence of these substances in the environment. The main topics addressed are: (a) the problems related to the...
Simultaneous analysis of 24 carbonyl compounds (alkanals, unsaturated, dicarbonylic and aromatic aldehydes and ketones) derivatized with 2,4-dinitrophenylhydrazine and 16 polycyclic aromatic hydrocarbons (PAHs) using a photodiode-array (PDA) and a fluorescence (FL) detector in series is proposed.The separation is carried out with a reversed-phase column and gradient elution using four solvents (acetonitrile,...
Utilizing liquid chromatography–mass spectrometry (LC–MS) for identification of polycyclic aromatic hydrocarbons (PAHs) has long been underrated, as the sensitivity for determination of PAHs directly by MS is very poor. In the present work a chlorination method for high-sensitive determination of PAHs by LC–MS is discussed. This method includes two steps: (1) chlorination of PAHs by the BMC method;...
A new procedure for optimizing PAHs separation in very complex mixtures by reverse phase high performance (RPLC) is proposed. It is based on changing gradually the experimental conditions all along the chromatographic procedure as a function of the physical properties of the compounds eluted. The temperature and speed flow gradients allowed obtaining the optimum resolution in large chromatographic...
Several methods of extraction were optimized to extract polycyclic aromatic hydrocarbons (PAHs), their nitrated derivatives and heavy n-alkanes from a highly adsorptive particulate matter resulting from the combustion of diesel fuel in a diesel engine. This particular carbonaceous particulate matter, collected at high temperatures in cordierite diesel particulate filters (DPF), which are optimized...
The strong affinity between polycyclic aromatic hydrocarbons (PAH) and the surface of gold colloids is investigated to device an extraction method for water samples. Within the 20–100nm particle diameter range, the 20nm gold nanoparticles showed the best extraction efficiencies for all the studied analytes. The new approach is combined to laser-excited time-resolved Shpol'skii spectrometry for the...
A method for determination of polycyclic aromatic hydrocarbons (PAHs) from aerosols was developed. Instead of conventionally used non-polar or slightly polar phenylmethylpolysiloxane column a highly polar, highly substituted, cyanopropyl column (VF-23 MS) was used for separation of PAHs. Based on hollow fiber micro-porous membrane liquid–liquid extraction (HF-MMLLE) a method was developed for sample...
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...
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