The Column - July 2007 - (Page 26)

Q&A The Column July 2007 It’s A Small World Microextraction by packed sorbent (MEPS) is a sample preparation technique that uses a fraction of the sample and reagents required by other commonly used preparation techniques. The Column spoke to Peter Dawes of SGE Analytical Science to find out more about the benefits — and applications — of this novel approach. What is microextraction by packed sorbent (MEPS)? MEPS is a different approach to sample preparation and sample handling. Basically, it is a miniaturized solid phase extraction (SPE) cartridge integrated into a microlitre capacity syringe. Instead of the millilitre volumes of solvent required for the extraction of samples on a conventional SPE cartridge, MEPS cartridges are capable of giving a total concentrated eluted volume of a few microlitres. The cartridge is integrated into the syringe, which can be any type of manual or automated syringe used in a gas chromatography (GC) or a liquid chromatography (LC) autosampler. Full automation of the sample preparation process and injection of the extracted sample directly into a conventional GC or LC system can be achieved using a conventional autosampler. A key aspect of MEPS is that the volume of solvent used to elute the analytes from the extraction process is of a suitable order of magnitude to be injected directly into a LC or GC system without any further concentration of the sample. Author: Peter Dawes E-mail: Why was it developed? In chromatographic analysis there are ways of achieving much greater resolving power and it is not so difficult to speed up the analysis beyond the levels achieved by many practitioners. The quality of separations and the technology associated with columns and detectors is constantly evolving, but although there have been advances in sample preparation techniques, the sample preparation part of the process tends to remain the rate-limiting step and source of most of the analytical errors. The analytical chemist needs more strings to his bow for selective sample preparation and matrix exchange before the chromatographic analysis. We first made a prototype many years ago of a micro-SPE device on the front of a syringe after it was suggested by Professor Pat Sandra from The Research Institute for Chromatography (RICHROM), Ghent, but this work was not pursued further. The system as it exists now came from a suggestion by Dr Mohamed Abdel-Rehim of Astra Zeneca, Sweden, who has been developing methods and publishing papers on the technique with Professor Lars Blomberg of Karlstad University, Sweden, since 2003. 26

Table of Contents for the Digital Edition of The Column - July 2007

Industrial-Scale Chromatography: A Cost- and Time-Effective Purification Solution
Do We Really Need Consultants?
Market Trends and Analysis
Dalian ISCC 2007 Review
It's A Small World

The Column - July 2007