Highly sensitive determination of estrone and estradiol in human serum by liquid chromatography–electrospray ionization tandem mass spectrometry

• Published in: Steroids 2007-10, Vol.72 (11), p.819-827
• Main Authors: Yamashita, Kouwa, Okuyama, Mitsunobu, Watanabe, Yoko, Honma, Seijiro, Kobayashi, Sayuri, Numazawa, Mitsuteru
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chromatography, Liquid; Electrospray ionization; Estradiol - blood; Estradiol - chemistry; Estradiol - isolation & purification; Estrogen; Estrone - blood; Estrone - chemistry; Estrone - isolation & purification; Female; Fundamental and applied biological sciences. Psychology; Humans; Liquid chromatography–tandem mass spectrometry; Picolinic Acids - chemistry; Picolinoyl ester; Selected reaction monitoring; Solvents - chemistry; Spectrometry, Mass, Electrospray Ionization - methods; Tandem Mass Spectrometry - methods; Vertebrates: endocrinology
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/j.steroids.2007.07.003

A highly sensitive and specific quantification method of estrone and estradiol in human serum was described based upon the use of picolinoyl derivatization and liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS) in a positive mode. Estrogens were treated with picolinoyl chloride hydrochloride or picolinic acid and 2-methyl-6-nitrobenzoic anhydride followed by a solid-phase extraction with ODS cartridge. Picolinoyl derivatization proceeded quantitatively even in a microscale, and the picolinoyl esters provided simple positive ESI-mass spectra showing [M + H] + as base peaks for these estrogens. The picolinoyl derivatives of these estrogens showed 100-fold higher detection response compared to underivatized intact molecules by LC–ESI-MS (selected reaction monitoring). Using this derivatization, estrogens spiked in the charcoal treated human serum samples were analyzed with limit of quantification (LOQ), intra-day accuracy and precision of 1.0 pg/ml, 96.0% and 9.9% for estrone, and 0.5 pg/ml, 84.4% and 12.8% for estradiol, respectively. Estrone and estradiol added to the crude serum samples were recovered with comparable LOQ and accuracy obtained for the charcoal treated serum samples as well.