English Abstract In this report a study is described on the fully
automated determination of desmethyldiazepam in rat serum. Isolation of
desmethyldiazepam from rat serum is with robotized solid-phase extraction
with a High-Hydrophobic Octadecylsilane sorbent by using the ASPEC
(Automatic Sample Preparation with Extraction Columns.) The solid-phase
purified extract is, after dilution, injected on a chromatographic system.
Subsequent clean-up of the extract is by column-switching. A "heart-cut" of
the precolumn eluate containing the relevant part of the extract
(desmethyldiazepam and the internal standard prazepam) is directed to the
analytical column. Detection is by UV-absorbance detection at 226 nm. The
data are collected, stored and processed on an analytical workstation. The
extraction recovery (+- standard deviation) is 83,3 +- 1,0)%. The precision
is 5,3% at 1,1 mg/l. The method is adapted to a concentration range from
0.05 to 5,0 mg/l starting with 150 mul serum. The resulting method is
completed by the introduction of a quality control to assure the quality and
the reliability of the results.
