Recent advances in microextraction by packed sorbent for bioanalysis.

Microextraction by packed sorbent (MEPS) is a new format for solid-phase extraction (SPE) that has been miniaturized to work with sample volumes as small as 10muL. The commercially available presentation of MEPS uses the same sorbents as conventional SPE columns and so is suitable for use with most existing methods by scaling the reagent and sample volumes. Unlike conventional SPE columns, the MEPS sorbent bed is integrated into a liquid handling syringe that allows for low void volume sample manipulations either manually or in combination with laboratory robotics. The key aspect of MEPS is that the solvent volume used for the elution of the analytes is of a suitable order of magnitude to be injected directly into GC or LC systems. This new technique is very promising because it is fast, simple and it requires very small volume of samples to produce comparable results to conventional SPE technique. Furthermore, this technique can be easily interfaced to LC/MS and GC/MS to provide a completely automated MEPS/LC/MS or MEPS/GC/MS system. This extraction technique (MEPS) could be of interest in clinical, forensic toxicology and environmental analysis areas. This review provides a short overview of recent applications of MEPS in clinical and pre-clinical studies for quantification of drugs and metabolites in blood, plasma and urine. The extraction of anti-cancer drugs, beta-blockers drugs, local anaesthetics, neurotransmitters and antibiotics from biological samples using MEPS technique will be illustrated. Copyright 2009 Elsevier B.V. All rights reserved.