Direct analysis of clomipramine in human plasma by microbore high performance liquid chromatography with column-switching

Abstract

SummaryAn automated microbore, liquid chromatographic method with column-switching was developed for the determination of clomipramine from human plasma samples. After direct injection of samples (60#L), plasma proteins and clomipramine were separated in size-exclusion mode using 20 % acetonitrile in 20 mM phosphate buffer (pH 7.0) on Capcell Pak MF Ph-1 precolumn (10 x 4mm I.D.). By valve switching, a fraction containing clomipramine was directed to an intermediate column for subsequent main separation on a microbore Cls column (250 x 1.5 mm I.D.) using 50 % acetonitrile in 20 mM phosphate buffer (pH 2.5) at 0.1 mL min -1. The method was advantageous for rapidity (total analysis time: 15min), reproducibility (C.V. < 4.8 %), and increased sensitivity (1 ng mL-1). The linearity of response was good (r e -> 0.999) over the concentration range 1-250 ng mL -1.

Restricted access materials and large particle supports for on-line sample preparation: an attractive approach for biological fluids analysis

“…Several ml of biological fluids can be directly injected on this extraction material without loss of performances [115,116]. Capcell Pak MF [115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133] and Capcell Pak SCX [134] materials were suitable tools for the direct determination of drug-containing biofluids.…”

Development and validation of high-performance liquid chromatographic methods for the determination of 14-benzodiazepines in bio-fluids

“…On-line automatic SPE devices were initially employed to preconcentrate in the cartridge the analytes present in a large volume of sample (71,74,143). On-line SPE devices forms part of the so-called 'column switching' or 'coupled column' techniques which include all those methods by which the direction of the mobile phase flow is changed by high pressure switching valves so that the effluent from one column is switched to another after a set time interval (144)(145)(146).…”

“…After LLE extraction 10 tricyclic antidepressants, their active metabolites and MAOIs in whole blood (432) or doxepin and its active metabolite desmethyldoxepin in plasma (417) were determined by HPLC coupled with MS/MS in ESI mode providing LOQ 0.2-2.0 ng mL -1 . A number of tricyclic antidepressants in oral fluid and plasma were extracted with an automated solid-phase extraction system (ASPEC XL) and simultaneously determined by LC-MS/MS with LOQ 10 ng mL -1 (145). Forty-eight antidepressants and antipsychotics in human serum were quantitated by HPLC-MS/MS when LOQ was below the therapeutic concentrations (398).…”

“…Clean-up was accomplished with successive 2 mL washes of 2% formic acid in water and methanol. Elution was done with 2 mL of dicloromethane/2-propanol/ammonium hydroxide (75:24.5:0.5,v/v/v) after drying cartridges by positive pressure with a flow of nitrogen(145). A fully automated on-line solid-phase extraction (ASPEC) was performed on cyanopropyl Isolute cartridges, for the determination of nortriptyline in human serum.…”