Microextraction in packed syringe (MEPS) utilizing methylcyanopropyl-silarylene as coating polymer for extraction of drugs in biological samples

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 to 11% 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 (R-2) for plasma samples were 0.99 for all runs using GC-MS and LC-MS-MS.