01812nas a2200289   4500008004100000022001400041245012900055210006900184260001600253300001000269490000800279520093300287653001501220653004101235653001401276653001101290653002401301653003501325100001401360700001601374700001501390700001301405700001701418700001501435700001701450856005501467       2002                        eng d  a0021-967300aInitial study of using a laminar fluid diffusion interface for sample preparation in high-performance liquid chromatography.0 aInitial study of using a laminar fluid diffusion interface for s  c2002 Apr 19  a33-400 v9543 a<p>This report describes a new microfluidic device called the H Filter for sample preparation prior to HPLC. The H Filters make possible a diffusional transfer of an analyte from a sample stream into a stream of a "receiver" fluid. Existing mathematical models can be used for optimizing experimental conditions. The authors have selected the extraction of the antibiotic cephradine from blood to demonstrate the utility of the new device. The extracts of blood samples spiked with cephradine levels between 0.2 and 100 microg/ml were analyzed using a C8 reversed-phase column and UV detection at 260 nm. The HPLC results were in good agreement with theory. The recovery of 32.2+/-2.8% was uniform over the entire range of cephradine concentrations. The new method completely avoids the use of centrifuges, that is otherwise typical for most current methodologies for the preparation of blood samples prior to HPLC analysis.</p>10aCephradine10aChromatography, High Pressure Liquid10aDiffusion10aHumans10aReference Standards10aSpectrophotometry, Ultraviolet1 aJandik, P1 aWeigl, B, H1 aKessler, N1 aCheng, J1 aMorris, C, J1 aSchulte, T1 aAvdalovic, N  uhttp://microfluidicsciences.com/drupal/?q=node/224