Preparation of a fluorescent derivative of benzoylecgonine, and preliminary studies of its application to the analysis of urine.
A sensitive high-performance liquid chromatographic method using 3-bromomethyl-6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone (Br-DMEQ) as a fluorescent labeling reagent is described for the determination of benzoylecgonine (BE) and ecgonine (EC). The Br-DMEQ derivatives of BE and EC were separated on a C18 column and detected at 455 nm with excitation at 370 nm. The detection limits of the proposed method were 18.7 fmol for BE and 12.5 pmol for EC at a signal-to-noise ratio of 3. Relative standard deviations of five replicate measurements were 1.94% (10 pmol) and 2.98% (50 pmol) for BE and 6.3% (250 pmol) and 5.62% (1.25 pmol) for EC. This method was applied to the determination of BE in human urine. BE was extracted from urine by solvent extraction with chloroform-isopropyl alcohol (9:1, v/v) solution. Levels of 2.5.10(-8) M BE in urine (25 pmol/ml) could be determined.
Nakashima
K
K
School of Pharmaceutical Sciences, Nagasaki University, Japan.
Okamoto
M
M
Yoshida
K
K
Kuroda
N
N
Akiyama
S
S
Yamaguchi
M
M
D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000652:urine; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D011810:Quinoxalines / Q000737:chemistry*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D011810:Quinoxalines; C052465:3-bromomethyl-6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone; C005618:benzoylecgonine; C005617:ecgonine; D003042:Cocaine