A new sensitive determination method of estradiol in plasma using peroxyoxalate ester chemiluminescence combined with an HPLC system

A new sensitive determination method of estradiol in a plasma sample using peroxyoxalate ester chemiluminescence was developed. Estradiol, which was e xtracted by liquid-liquid extraction using ethyl acetate from plasma, was d erivatized with dansyl-chloride (DNS-Cl) and separated by reverse-phase HPL C. The performance of four oxalates, bis(trichlorophenyl) oxalate (TCPO), b is(2,4-dinitrophenyl) oxalate (DNPO), bis(pentafluorophenyl) oxalate (PFPO) , and bis[4-nitro-2-(3,6,9-trioxadecyloxycarbonyl)phenyl] oxalate (TDPO), w ere evaluated using the static system, and DNPO was found to have the most sensitive and stable chemiluminescence at a H2O2 concentration of 30 mM. HP LC-chemiluminescence system using DNPO for the determination of estradiol w as established. The detection limit of dansylated-estradiol (DNS-E2) was 15 fmol (4 pg) in the standard solution and 44 fmol (12 pg) in the rat plasma sample at S/N = 3. Copyright (C) 2000 John Wiley & Sons, Ltd.