MONITORING PROPOFOL SERUM LEVELS BY RAPID AND SENSITIVE REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY DURING PROLONGED SEDATION IN ICU PATIENTS

A quick and sensitive reversed-phase high-performance liquid chromatography (HPLC) method has been developed in order to determine the concentration of Propofol (2, 6 diisopropyl- phenol) in human serum. Propofol can be isolated from serum by adding 0.5 mL precipitating solution. This consists of an acetonitrile and perchloric acid (67:33, v/v) mixture, which also contains dibutylphthaiate (2 mg/100ml_) as internal standard. The sample is then mixed for 1 min on a vortex-mixer. The endogenous serum substances precipitated by acetonitrile and perchloric acid are further separated by centrifugation. The supernatant is directly injected into the HPLC system. A 250- x 4.6-mm column, packed with 10-fim Spherisorb reversed-phase octadecylsilane particles (C18), is used for chromatographic separation. The mobile phase consists of an acetonitrile-water mixture (67:33 ratio) with 0.4 mL acetic acid (pH 4). Propofol is monitored by a UV-visible detector at 270 nm and 0.1-0.002 absorbance units full scale (AUFS). The detection limit of Propofol (in human serum) is 0.1 mg/L for a 20-jllL injection volume. The time of the assay is less than 20 min, including sample preparation. © Oxford University Press 1992.