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Acer 30-32. 08038 BARCELONA |
SGE MEPS Micro Extraction by Packed Sorbent
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SGE MEPS Micro Extraction by Packed Sorbent |
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 ¿Qué
es MEPS?MEPS es Micro Extraction by Packed Sorbent y es un nuevo desarrollo en el campo de la preparación y manipulación de muestras. MEPS es la miniaturización de la SPE convencional de volúmenes de lecho empacado de mililitros a microlitros. La aproximación de MEPS a la preparación de la muestra es adecuada para fases reversas, fases normales, fases de modo mixto o de intercambio iónico. MEPS está disponible en una amplia variedad de fases de SPE convencionales. El cartucho (Pendiente de Patente), contiene la fase estacionaria y es solidario con la aguja de la jeringa (ver Figura 1). ¿Por qué MEPS? Históricamente, muchos métodos de preparación de muestras utilizan la extracción líquido-líquido (LLE) que requiere grandes volúmenes de muestra. Las ventajas de la SPE sobre la LLE son que SPE requiere mucho menos tiempo, puede evolucionar a una técnica totalmente automatizada, necesita mucho menos solvente y ofrece selectividad. MEPS realiza las mismas funciones que SPE: la eliminación de componentes de la matriz que interfieren y el aislamiento y la concentración selectiva de los analitos. MEPS aumenta las ventajas de la SPE convencional de las maneras siguientes:
Tamaño de Muestra y
Sensibilidad
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 ¿El efecto memoria es
significativo en MEPS?Los accesorios de SPE se han considerado tradicionalmente de un solo uso. La ingeniería de precisión usada en el diseño y la fabricación de MEPS permiten simples etapas de lavado y la consiguiente reutilización del cartucho. Para demostrar este punto se han extraído fenoles de agua residual y se ha medido el arrastre de muestra entre experimentos. En la Figura 5 se muestran los cromatogramas de tres extracciones de 10 µL. La primera se ha etiquetado como "fenoles 25 ppb", la segunda "extracción 2" y la tercera "extracción 3". Se ve claramente que en los primeros 10 µL de metanol se eluyen todos los fenoles. Una de las razones generalmente aducidas para el uso de cartuchos SPE desechables es el problema del efecto memoria. El resultado de 5 estudios se resume en la Tabla 3. Usando una serie de lavados con eluyente y luego con solución de lavado, se ha eliminado virtualmente el efecto memoria. Con un ciclo de tiempo medido en segundos, para MEPS este lavado se efectúa en menos de 5 minutos. Para obtener un resultado equivalente en SPE convencional, se requeriría más de una hora y el uso de cantidades bastante significativas de solventes. Resumen La Tabla 4 resume la comparación de MEPS, SPME y SPE convencional. MEPS requiere mucho menos tiempo que SPE o SPME, y muestra una recuperación y sensibilidad bastante superiores. MEPS también elimina cualquier etapa intermedia entre la preparación de la muestra y la inyección en el cromatógrafo de Gases o de Líquidos. |
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| Publicaciones disponibles en MEPS | Tipo | |
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Extraction of Phenols from Waste Water using
Micro Extraction by Packed Sorbent (MEPS). To demonstrate the usefulness of MEPS for dilute samples with a relatively simple matrix, a surrogate wastewater sample was prepared from clear phenol free waste water spiked with either 25 ppb or 250 ppt phenols. |
Aplicación. 345Kb |
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On-Site Sample Preparation Using MEPS for Waste
Water Analysis. |
Aplicación. 254Kb |
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MEPS for pollutants and small volume samples. |
Ejemplos. 506Kb |
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Application of MEPS coupled with Gas
Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF MS) in
Analysis of Brominated Flame Retardants in Waste Water. |
Artículo. 284Kb |
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Development and validation of a liquid chromatography and tandem
mass spectrometry method for determination of roscovitine in plasma
and urine samples utilizing on-line sample preparation. Roscovitine, a purine analogue that selectively inhibits cyclin-dependent kinases, has been considered as a potential anti-tumor drug. The determination of roscovitine in plasma and urine was performed using microextraction in packed syringe as on-line sample preparation method with liquid chromatography and tandem mass spectrometry. The sampling sorbent utilized was polystyrene polymer. 2H3-lidocaine was used as internal standard. The limit of detection for roscovitine was as low as 0.5 ng/mL and the lower limit of quantification was 1.0 ng/mL. The accuracy and precision values of quality control samples were between±15% and≤11%, respectively. The calibration curvewas obtained within the concentration range 0.5–2000 ng/mL in both plasma and urine. The regression correlation coefficients for plasma and urine samples were ≥0.999 for all runs. The present method is miniaturized and fully automated and can be used for pharmacokinetic and pharmacodynamic studies. |
Artículo. 162Kb |
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Development of a
molecularly imprinted polymer based solid-phase extraction of local
anaesthetics from human plasma. Molecular imprints selective for a homologous series of local anaesthetics, including bupivacaine, ropivacaine and mepivacaine, were prepared and the resultant polymers were used for solid-phase extraction of human plasma. The template was a structural analogue, pentycaine, which was imprinted in methacrylic acid–ethylene glycol dimethacrylate copolymers. Equilibrium ligand binding experiments using radiolabelled bupivacaine were performed to characterize the imprinted polymers, as well as to identify optimal conditions for selective extraction of plasma samples. Dilution of the plasma prior to extraction with citrate buffer pH 5.0 containing ethanol and Tween 20 was found optimal for selective imprint–analyte binding, and for reduction of non-specific adsorption of lipophilic contaminants to the hydrophobic MIP surface. Wash steps using 20% methanol in water followed by a solvent switch to 10% ethanol in acetonitrile removed contaminants and strengthened the selective imprint–analyte binding. Elution under basic conditions using triethylamine–water–acetonitrile mixtures recovered bupivacaine in 89% yield with superior selectivity over elution under acidic conditions. The final protocol extracted trace levels of ropivacaine and bupivacaine from human plasma and allowed determination of bupivacaine in the range of 3.9–500nmol L−1 and ropivacaine in the range of 7.8–500 nmol L−1 with inter-assay accuracies of 94–99 and 95–104%, respectively. This present investigation provides an improved understanding of approaches available for optimization of protocols for molecular-imprint based solid-phase extraction of plasma samples. |
Artículo. 123Kb |
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Fast and sensitive
environmental analysis utilizing microextraction in packed syringe
online with gas chromatography–mass spectrometry. Determination of
polycyclic aromatic hydrocarbons in water. A new sensitive, selective, fast and accurate technique for online sample preparation was developed. Microextraction in a packed syringe (MEPS) is a new miniaturised, solid-phase extraction (SPE) technique that can be connected online to GC or LC without any modifications. In MEPS approximately 1mg of the solid packing material is inserted into a syringe (100–250 ml) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising. It is very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. The determination of polycyclic hydrocarbons (PAHs) in water was performed using MEPS as sample preparation method online with gas chromatography and mass spectrometry (MEPS–GC–MS). The results from MEPS as sample preparation were compared with other techniques such as stir bar sorptive extraction (SBSE) and solid-phase microextraction (SPME). The method was validated and the standard curves were evaluated by the means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 5–1000 ng/L. The MEPS applied polymer (silica-C8) could be used more than 400 times before the syringe was discarded. The extraction recovery was about 70%. The results showed close correlation coefficients (R > 0.998) for all analytes in the calibration range studied. The accuracy of MEPS–GC–MS was between 90 and 113% and the inter-day precision (n = 3 days), expressed as the relative standard deviation (RSD%), was 8–16%. MEPS reduced the handling time by 30 and 100 times compared to SPME and SBSE, respectively. |
Artículo. 166Kb |
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New trend in sample
preparation: on-line microextraction in packed syringe for liquid
and gas chromatography applications I. Determination of local anaesthetics in human plasma samples using gas chromatography–mass spectrometry. A new technique for sample preparation on-line with LC and GC–MS assays was developed. Microextraction in a packed syringe (MEPS) is a new miniaturised, solid-phase extraction technique that can be connected on-line to GC or LC without any modifications. In MEPS approximately 1mg of the solid packing material is inserted into a syringe (100–250 l) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising. It is very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. This paper presents the development and validation of a method for microextraction in packed syringe MEPS on-line with GC–MS. Local anaesthetics in plasma samples were used as model substances. The method was validated and the standard curves were evaluated by the means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 5–2000 nM. The applied polymer could be used more than 100 times before the syringe was discarded. The extraction recovery was between 60 and 90%. The results showed close correlation coefficients (R > 0.99) for all analytes in the calibration range studied. The accuracy of MEPS–GC–MS was between 99 and 115% and the inter-day precision (n = 3 days), expressed as the relative standard deviation (R.S.D.%), was 3–10%. |
Artículo. 155Kb |
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Microextraction
in packed syringe (MEPS) for liquid and gas chromatographic
applications. Part II—Determination of ropivacaine and its metabolites in human plasma samples using MEPS with liquid chromatography/tandem mass spectrometry. A new technique for sample preparation on-line with liquid chromatographic/tandem mass spectrometric (LC/MS/MS) assay was developed. Microextraction in a packed syringe (MEPS) is a new miniaturized, solid-phase extraction technique that can be connected on-line to gas or liquid chromatography without any modifications. In MEPS 1 mg of the solid packing material is inserted into a syringe (100–250 μl) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising, very easy to use, fully automated, of low cost and rapid in comparison with previously used methods. This paper presents the development and validation of a method for MEPS on-line with LC/MS/MS. Ropivacaine and its metabolites (PPX and 3-OH-ropivacaine) in human plasma samples were used as model substances. The method was validated and the calibration curves were evaluated by means of quadratic regression and weighted by the inverse of the concentration, 1/x, for the calibration range 2–2000 nM. The applied polymer could be used more than 100 times before the syringe was discarded. The extraction recovery was between 40 and 60%. The results showed high correlation coefficients (R2 > 0.999) for all analytes in the calibration range studied. The accuracy, expressed as a percentage variation from the nominal concentration values, ranged from 0 to 6%. The precision, expressed as the relative standard deviation, at three different concentrations (quality control samples) was consistently about 2–10%. The limit of quantification was 2 nM. |
Artículo. 149Kb |
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The Extraction of Saliva
for The Analysis of Basic Drugs Residues Using MEPS™-GCMS. |
Artículo. 206Kb |
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The Micro-Extraction and
Detection of Phenolic Anti-Oxidants from Cereal Products Using MEPS™-GCMS. |
Artículo. 967Kb |
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Measuring Fruit Juice
Adulteration by Changes in Flavonoid Content Using MEPS™ and HPLC. |
Artículo. 701Kb |
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The Extraction and
Analysis of Urinary Antitussive Metabolites using MEPS™ and ESI-LCMSn. Microextraction Packed Sorbent (MEPS™) is an adaptation of SPE into a miniaturized device with a typical void volume of less than 10 μL. With operating volumes of this scale and its compatibility with autosampler syringes, MEPS™ allows the specificity of the solid-phase process to be harnessed for digital chromatography using discontinuous changes in solvent polarity. The eluant volumes are sufficiently small to be injected directly into a HPLC system and therefore permit the on-line use of solid-phase extraction methodology in real time with the HPLC. |
Artículo. 122Kb |
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MEPS: A New
Technique for the Analyisis of Small Brominated and Chlorinated
Aromatic Compounds in Wine. The wine industry has long suffered from TCA (2,4,6-trichloroanisole) and TBA (2,4,6 tribromoanisole) contamination or “cork” taint. These compounds more recently has been found to be present in corks, packaging material, cardboard boxes, wooden products and many other materials. Only 1-2 ng/l of TCA or TBA is required to give wine the “musty” aroma associated with cork taint. It has been proposed that chlorophenols are the precursor for TCA (Fig1). As dioxins are known to be present as contaminants in chlorophenol formulations (1) they might therefore also be present in the wine corks, a hypothesis that needs further invesitigation. In this work, the analysis of TCA and TBA is performed by a new technique for sample preparation called Microextraction by Packed Sorbent (MEPS). This technique in combination with different GCMS techniques is described below and compared with other methods. |
Artículo. 318Kb |
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The application of
MEPS for the on-site preparation of water samples. MEPS uses a barrel insert and needle (BIN) device to reduce Solid-Phase Extraction (SPE) to a micro-scale suitable for small volume samples and for the on-line adaptation of conventional SPE techniques. Because the SPE cartridge (BIN) is incorporated into the needle assembly of a gas-tight syringe, MEPS is also a simple field-portable SPE device that may be operated manually without need for sampling pumps or, alternatively, may be incorporated into robotic samplers. To demonstrate the application of MEPS we report the qualitative field use of C18-MEPS for the sampling of water bodies in both industrial and urban environments. Water samples were extracted on-site and then the MEPS syringes were transported back to the laboratory overnight for elution and analysis of the retained components. C18-MEPS was used to extract samples (100-1000 μL) of water from industrial drains and stormwater pipes to recover semi-volatile residues for GCMS analysis (Fig 1-3). The technique was also applied to sampling droplets on surface extracts of paint for non-destructive surface profiling (Fig 2). Analysis of the unknown samples was qualitative but sufficiently sensitive to detect industrial discharge residues associated with grinding coolants, packaging materials and other contaminants. Naturally occurring leachates from vegetation were also detectable. Droplet extraction of a painted surface was performed in reversed-phase mode (water extract on C18 sorbent) and allowed the surface to be profiled for comparative purposes. |
Artículo. 926Kb |
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The Integration of
Microextraction Packed Sorbent (MEPS) into Multidimensional
Strategies. LC-GC approaches to analysis are particularly attractive because they combine the selectivity of solidphase sorbents in the first dimension with the separating power and peak capacity of a capillary GC column in the second and subsequent dimensions. Widespread use of the technique is limited because of the difficultly in desolvating the stream from the LC dimension without the solvent vapour passing down the GC column in significant quantity. An alternative approach to elution chromatography in the first dimension is to harness the specificity of the solid-phase process for digital chromatography using discontinuous changes in solvent polarity (Fig 1). Digital chromatography on a small sorbent bed reduces the volume of mobile phase to discrete plugs that are sufficiently small to be injected directly into a GC with a large volume injector or, alternatively, subsampled into a conventional split/splitless injector. Microextraction Packed Sorbent (MEPS) is an adaptation of SPE that incorporates all the desirable characteristics into a miniaturized device with a typical void volume of less than 10 μL. With operating volumes of this scale and its compatibility with autosampler syringes, the MEPS format is the ideal for a digital LC - elution GC approach to analysis. In this application, we use the selectivity of an argentation sorbent to speciate a mixture of fatty acid methyl esters on the basis of unsaturation in the first dimension and then to separate groups by conventional non-polar GCMS in the second dimension. |
Artículo. 740Kb |
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Argentation Based
(MEPS) for the Analysis of FAMES by GCMS. Micro Extraction by Packed Sorbent (MEPS) is an adaptation of SPE that incorporates all the desirable characteristics into a miniaturized device with a typical void volume of less than 10 μL. With operating volumes of this scale and its compatibility with autosampler syringes, MEPS allows the specificity of the solid-phase process to be harnessed for digital chromatography using discontinuous changes in solvent polarity (Fig 1). The eluant volumes are sufficiently small to be injected directly into a GC with a large volume injector or, alternatively, subsampled into a conventional split/splitless injector and therefore MEPS can be used as a digital LC - elution GC approach to analysis. In this application, we use the selectivity of an argentation sorbent to speciate a mixture of fatty acid methyl esters on the basis of unsaturation in the first dimension and then to separate groups by conventional non-polar GCMS in the second dimension. |
Artículo. 626Kb |
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Microextraction
Packed Sorbent (MEPS): Analysis of Food and Beverages . MEPS is a development of conventional SPE that has miniaturised the sorbent bed so that it can be incorporated into the sample path without voids. Typically, a MEPS method reduces sample and reagent consumption by several orders of magnitude over conventional methods. Extraction performance is comparable to conventional SPE because the MEPS sorbent bed retains the same dimensional ratios of the conventional device and adaption of existing methods is achieved by scaling all steps in proportion to the bed volumes (typically 1 mL for SPE and 10 μL for MEPS). The small scale of the MEPS device allows elution in a small volume and so the entire extract may be analyzed rather than only using a portion of the prepared extract in a conventional experimental design. SPE and MEPS are not the same as SPME or SBSE techniques. The former rely on solvent desorption and use a mono-layer extraction surface with a very large surface area. The latter are immobilised liquid extraction techniques that are typically used in thermal desorption mode. |
Artículo. 484Kb |
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The Determination of
Urinary Metabolites of Dextromethorphan by Meps™-Esi-Lcms. |
Artículo. 792b |
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| MEPS Online KIT | Hoja Producto. 408Kb |
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| MEPS | Hoja Producto. 315Kb |
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Copyright© 2006-2014 CromLab S.L. Prohibida la reproducción total o parcial sin consentimiento escrito del propietario.
Flexible
y de fácil uso
El
cartucho MEPS se instala fácilmente en la jeringa y se asegura mediante
una tuerca de cierre. El etiquetado individual de cada cartucho asegura
la fase estacionaria correcta en cada extracción. 
En la
Figura 3 se muestra la extracción de metabolitos de xantina de orina
humana cruda con un cartucho MEPS de C18 antes del análisis por GC-MS
donde puede verse como las matrices difíciles como la orina
humana se procesan fácilmente con MEPS. En este ejemplo 100 µL de orina humana se aspiraron a través de un cartucho MEPS C18 (acondicionado con metanol y
agua, y lavado con agua). Las xantinas adsorbidas se eluyeron con 30 µL
de metanol, y 2 µL se inyectaron en una columna
BPX5 para su análisis por GC-MS.