Analysis of fluorescein isothiocyanate derivatized amphetamine and analogsin human urine by capillary electrophoresis in chip-based and fused-silicacapillary instrumentation
A. Ramseier et al., Analysis of fluorescein isothiocyanate derivatized amphetamine and analogsin human urine by capillary electrophoresis in chip-based and fused-silicacapillary instrumentation, ELECTROPHOR, 19(16-17), 1998, pp. 2967-2975
Amines can easily be derivatized with fluorescein isothiocyanate isomer I (
FITC) and analyzed by capillary electrophoresis (CE) using alkaline buffers
with or without dodecyl sulfate micelles. This paper reports the CE analys
is of FITC-derivatized amphetamine, methamphetamine, 3,4-methylenedioxymeth
amphetamine and beta-phenylethylamine in human urine using chip-based and f
used-silica capillary instrumentation with laser-induced fluorescence detec
tion. Data obtained via direct labeling of fortified urine are compared to
those generated after FITC labeling of urinary extracts that were prepared
by solid-phase extraction using a copolymer phase. For a urine volume of 5
mL with a "spiked amine": FITC ratio of 1:250, the latter approach was foun
d to provide a sensitivity that Is relevant for toxicological drug screenin
g and confirmation (about 200 ng/mL urine). With direct labeling of 10 mu L
urine that was alkalinized and diluted for derivatization, the limit of id
entification was determined to be about 10 mu g/mL, a value that is too hig
h for practical purposes. Compared to fused-silica capillaries, electrophor
esis in microstructures is shown to provide faster separations and higher e
fficiencies without loss of accuracy and precision.