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 MEPS online SPE for PAL Systems
SGE Analytical Science (www.SGE.com) introduced the new MEPS option (Micro Extraction by Packed Sorbent) for the PAL Series of CTC Autosamplers. MEPS is the miniaturization of conventional SPE packed bed devices from milliliter bed volumes to microliter volumes. The MEPS approach to sample preparation is suitable for reversed phases, normal phases, mixed mode or ion exchange chemistries. MEPS is available in a variety of common SPE phases. The cartridge (Patent Pending) contains the stationary phase, and is built into the syringe needle. With a typical void volume of a few µL, the MEPS elution is compatible with GC and LC inlets making it ideal for automated on-line SPE on the CTC PAL platform.
This technique works very well in combination with Large Volume Injections (LVI) on the OPTIC injector. The LVI makes the total setup very robust and easy to use.
MEPS Syringe with built in SPE cartridge
Publications:
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
Mohamed Abdel-Rehim. Journal of Chromatography B, 801 (2004) 317–321
<< Read Abstract >>
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 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. 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%.
Fast and sensitive environmental analysis utilizing microextraction in packed syringe online with gas chromatography–mass spectrometry
Determination of polycyclic aromatic hydrocarbons in water
Aziza El-Beqqali, Anders Kussak, Mohamed Abdel-Rehim. Journal of Chromatography A, 1114 (2006) 234–238
<< Read Abstract >>
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.
Quantitative analysis of methadone in human urine samples by microextraction in packed syringe-gas chromatography-mass spectrometry
(MEPS-GC-MS)
Aziza El-Beqqali,Mohamed Abdel-Rehim. J. Sep. Sci. 2007, 30, 2501 – 2505
<< Read Abstract >>
A method for the simultaneous analysis of methadone in urine samples by microextraction
in a packed syringe online with GC-MS (MEPS-GC-MS) is described. The new method reduced the sample handling and the detection limit by two- to seven-fold
compared to published methods. Using a quantitation method based on the calculation of analyte concentration by comparison to an internal standard, we were able
to measure methadone levels consistent with values reported for healthy individuals. The intra-assay precisions (RSD) of the method using quality control (QC) samples
at three different concentration levels were about 11–14% (n = 6). The interassay precisions (RSD) were 11–15% for methadone in urine samples (n = 18). The accuracy
varied from 89 to 109% for intra-assay (n = 6), and 97 to 107% for inter-assay (n = 18). The regression correlation coefficients (r2) were over 0.99 in all experiments.
Microextraction in Packed Syringe (MEPS) Utilizing Methylcyanopropyl-Silarylene as Coating Polymer for
Extraction of Drugs in Biological Samples
Mohamed Abdel-Rehim; Marie Dahlgren; Lars Blomberg; Saturnin Claude; Raphael Tabacchi. Journal of Liquid Chromatography & Related Technologies, 29:17, 2537 - 2544
<< Read Abstract >>
Microextraction in packed syringe (MEPS) is a new technique for miniaturised
solid-phase extraction that can be connected online to GC or LC. In this work, a liquid polymer was used as coating polymer on a filter in a 10 mL and
250 mL syringe to handle small sample volumes (.10 mL plasma). Ropivacaine in plasma samples was used as model substance. The validation of the methodology
showed that the accuracy values of quality control samples (QC) were in the range of 103%–114% for GC-MS, and 98–101% for LC-MS-MS. The precisions, given
as relative standard deviation (R.S.D.) were in the range 1.9 to11% for Inter- and intra-day precisions. The standard curves were obtained within the concentration
ranges 5-2,000 nM in human plasma samples. The regression correlation coefficients (R2) for plasma samples were 0.99 for all runs using GC-MS and LC-MS-MS.
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