Dynamics of organic compound extraction from water using liquid-coated fused silica fibers

Louch, Derek.; Motlagh, Safa; Pawliszyn, Janusz

doi:10.1021/ac00034a020

Cited by 590 publications

(313 citation statements)

References 14 publications

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“…26,27 However, in this model, the micro-structure geometry was ignored due to the fact that our study was focused on the macro-scale kinetic feature of extraction, in which extraction is fully controlled by the diffusion layer. 28 A refined mesh involving 92,000 finite elements was used in the present analysis. Increasing the number of elements does not improve the quality of the solution, but does increases the computational costs.…”

Section: Numerical Simulationmentioning

confidence: 99%

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Calibrant Free Sampling and Enrichment with Solid-Phase Microextraction: Computational Simulation and Experimental Verification

Alam

Ricardez‐Sandoval

Pawliszyn

2017

Ind. Eng. Chem. Res.

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Despite the benefits of diffusion-based calibrant-free sampling based on solid-phase microextraction (SPME), this quantification approach is often underestimated due to an inadequate understanding of how extraction parameters influence the extracted amount and quantification of analytes. Currently, application of this approach for complex samples with binding matrix components is very limited. This study presents the development of a computational model that is used to identify the critical parameters for the diffusion-based sampling. Simulations are conducted under simultaneous variations in mass transfer and adsorptive surface binding constants, and the presence of a binding matrix component in the sample. The simulation results correlate well with previously reported experimental data, and improve the predictions when compared to previously introduced semi-empirical models. This work enhanced basic understanding of physical processes involved in analyte quantification with SPME, which is of benefit when performing experimental designs, particularly where traditional calibration methods are not suitable.………………………………………………………………………………..

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Section: Numerical Simulationmentioning

confidence: 99%

“…28 The most common binding principle is the reversible binding between the analyte (A) and matrix component (B) dominated by the association constant (Ka). 23 Binding of the analyte with the matrix results in a decrease in its free concentration in the sample.…”

Section: Effect Of Binding Matrix Components On Diffusive Samplingmentioning

confidence: 99%

Calibrant Free Sampling and Enrichment with Solid-Phase Microextraction: Computational Simulation and Experimental Verification

Alam

Ricardez‐Sandoval

Pawliszyn

2017

Ind. Eng. Chem. Res.

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“…Therefore, the aqueous solution/ membrane and membrane/headspace interfaces can be simplified into one aqueous solution/headspace interface. Hence, the equations developed by Pawliszyn and coworkers 17 can be used to describe quantitatively the extraction behavior in our hollow-fiber-membrane IR sensor. The equation they derived is based on equilibrium conditions:…”

Section: Introductionmentioning

confidence: 99%

“…In the conventional method of sampling a headspace, a three-phase system, which involves mass transfer in three phases and across two interfaces, is typically used to describe the extraction process. 11,17 In such a three-phase system, mass transfer in the headspace is considered to be a very fast process and the two interfaces, the aqueous solution/headspace and the headspace/hydrophobic film, have a major influence on the extraction efficiency. For our proposed system, mass transfer from the aqueous solution to the IR sensing element involved three interfaces: aqueous solution/membrane, membrane/ headspace, and headspace/hydrophobic film.…”

Section: Introductionmentioning

confidence: 99%

An Infrared Evanescent Wave Sensing System Coupled with a Hollow Fiber Membrane for Detection of Volatile Organic Compounds in Aqueous Solutions

Wei

Yang

2005

ANAL. SCI.

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We have developed an on-line sensing method for the detection of volatile organic compounds (VOCs) in contaminated aqueous solutions by combining a microporous hollow fiber membrane with an infrared (IR) sensing system. Polypropylene microporous hollow fibers were used to separate the VOCs from the aqueous solution into the hollow fibers, which were purged countercurrently for detection by the IR sensing systems. An evanescent-wave-type IR sensing system was used to detect the VOCs that were purged from the hollow fibers. The sensing element was coated with polyisobutylene (PIB) to concentrate the VOCs for their detection. To study the performance of this system, we examined a number of factors, such as the purging flow rate, the sample flow rate, and the volatilities of the VOCs. The results indicate that an increase in the purging flow rate reduces the analytical signal significantly, especially for purging flow rates >2 mL/min. The pumping flow rate for the aqueous sample also influenced the analytical signals, but far less sensitively. The volatilities of the examined compounds also affected the analytical signals: the higher the volatility of the compound, the lower the intensity of the analytical signals and the shorter the time required to reach the equilibrium signal. From an examination of the dynamic range of this proposed method, a regression coefficient >0.994 was obtained for concentrations below 250 mg/L, even under non-equilibrium conditions. The response time of the system was studied in an effort to examine the suitability of using this sensing method for automatic detection. The results indicate that new equilibrium conditions were established within 3 min for highly volatile compounds, which suggests that on-line monitoring of the levels of VOCs can be performed in the field.

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“…SPME is also based on the use of an adsorbant to concentrate compounds contained in liquid or solid samples. The sample is put into a hermetical closed vial [3][4][5][6][7], whose volume goes from 10 to 30 mL. Generally, a gazeous phase stays above a known volume of sample.…”

mentioning

confidence: 99%

Extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) by solid phase micro-extraction/supercritical fluid chromatography (SPME/SFC)

Lesellier¹

1999

Analusis

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The analysis of the Polycyclic Aromatic Hydrocarbons (PAH) diluted in water samples at very low concentration levels requires to concentrate them before the separation step.The French AFNOR standard, applicable for six PAHs, recommends to quantify them at a level of 10 ng/L for three of them in the drinking water, whereas the US environmental protection agency has listed 16 PAHs, that have to be quantified in the waste water.To extract these compounds from water based matrix, the liquid/liquid extraction (LLE) is mainly used, and HPLC is a suited separation method for these low volatile compounds. However, solid phase extraction (SPE) is became leading technique to replace liquid/liquid extraction [1,2], because trapping compounds in a solid adsorbant set in a cartridge, a disk (off-line), or in a pre-column (on-line), strongly reduces the use of solvents.Solid phase micro-extraction (SPME) is another precontration method which can be used to replace the LLE. SPME is also based on the use of an adsorbant to concentrate compounds contained in liquid or solid samples. The sample is put into a hermetical closed vial [3][4][5][6][7], whose volume goes from 10 to 30 mL. Generally, a gazeous phase stays above a known volume of sample. The adsorbant is a fiber glued into a stainless steel plunger, inserted into a holder. When a vial is traited, the plunger is pulled back, drawing the fiber into the needle of the holder.The fiber is either outside the needle during the adsorption or the desorption steps, or inside the needle when the needle is introduced or drawn out the vial piercing the septum or from the split/splitless injector.The fiber can be placed into the gazeous phase above the samples, which corresponds to the head space SPME extraction [6-9], or into the liquid sample, which corresponds to direct SPME [3][4][5]. These two SPME methods are complementary one from another, the first one concentrating the volatile componds (the BTEX for instance), and the second one the less volatile (chloro-phenols, pesticides).The stirring conditions [4,10], the thickness of the solidphase coating of the silica fiber support [4] and the coated solid phase nature [11] have an effect on the speed required to reach the equilibria and determine the minimum adsorption time.Other parameters can change the quantity of trapped compounds: sample pH [11,12], addition of salts [7,13], trapping temperature. Knowledge of the influence of these parameters is needed in order to decrease the detection limits of the compounds. 363Extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) by solid phase micro-extraction/supercritical fluid chromatography (SPME/SFC) E. Lesellier LETIAM, IUT D'Orsay, Plateau du Moulon, F-91400 Orsay, FranceAbstract. Solid phase micro-extraction (SPME) is a clean and simple pre-concentration method. Previously used for trace analysis of volatil compounds, the use of SPME was extended to non volatil molecules with the development of an SPME /HPLC interface. This new interface allows the extraction and the a...

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Dynamics of organic compound extraction from water using liquid-coated fused silica fibers

Cited by 590 publications

References 14 publications

Calibrant Free Sampling and Enrichment with Solid-Phase Microextraction: Computational Simulation and Experimental Verification

Calibrant Free Sampling and Enrichment with Solid-Phase Microextraction: Computational Simulation and Experimental Verification

An Infrared Evanescent Wave Sensing System Coupled with a Hollow Fiber Membrane for Detection of Volatile Organic Compounds in Aqueous Solutions

Extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) by solid phase micro-extraction/supercritical fluid chromatography (SPME/SFC)

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