2-(5-Benzoacridine)ethyl-p-toluenesulfonate
(BAETS), a dual-sensitive probe, was reacted with bile acids
in the presence of K2CO3 catalyst in dimethyl sulfoxide
(DMSO) solvent to give BAETS–bile acid derivatives.
Derivatives exhibited intense fluorescence (FL) with an
excitation maximum at λex 270 nm and an emission
maximum at λem 510 nm. MS analysis using APCI-MS
indicated that derivatives had excellent APCI-MS ionizability
with percentage ionization δ values changing from 0 to
88.83% in aqueous acetonitrile and from 0 to 89.15% in
aqueous methanol. The collision induced dissociation spectra
of m/z [M + H]+ contained specific fragment ions at m/z
[M + H−H2O]+, [M + H−2H2O]+, [M + H−3H2O]+, 347.3,
and 290.1. Repeatability was good for LC separation of
BAETS–bile acid derivatives with aqueous acetonitrile as
mobile phase. The relative standard deviations (RSDs) of
retention time and peak area at 6.6 nmol mL−1 levels with
fluorescence detection (FL) were from 0.045 to 0.072% and
from 2.16 to 2.73%, respectively. Excellent linear responses
were observed, with regression coefficients >0.9995. The FL
detection limits (S/N=3) were in the range of 18.0–36.1
fmol. The online APCI-MS detection limits are in the range
of 500–790 fmol (at a signal-to-noise ratio of 3).
Keywords 2-(5-Benzoacridine)ethyl-p-toluenesulfonate .
Bile acids . Column liquid chromatography . Fluorescence
detection . Mass spectrometry
DOI 10.1007/s00216-010-3467-4