Automated liquid membrane extraction for high-performance liquid chromatography of Ropivacaine metabolites in urine

An automatic method for the determination of metabolites of Ropivacaine in urine was set up. It utilizes supported liquid membrane extraction for samp le clean-up and enrichment, followed by ion-pair chromatography determinati on using UV detection. The extraction was very selective with no observed i nterfering compounds from the urine matrix, permitting simple isocratic chr omatographic analysis. The detection limits for spiked urine samples were 2 -18 nM for the different compounds. The repeatability was 1-3% (RSD) with a n internal standard that was also extracted, and about twice without this s tandard. A throughput of 3.3 samples per hour was achieved and the liquid m embrane was stable for more than a week. (C) 2000 Elsevier Science BN. All rights reserved.