Yamashita Kouwa, Takahashi Madoka, Tsukamoto Satoshi, Numazawa Mitsuteru, Okuyama Mitsunobu, Honma Seijiro
Faculty of Pharmaceutical Science, Tohoku Pharmaceutical University, 4-1 Komatsushima 4-Chome, Aoba-ku, Sendai 981-8558, Japan.
J Chromatogr A. 2007 Nov 30;1173(1-2):120-8. doi: 10.1016/j.chroma.2007.10.023. Epub 2007 Oct 12.
Simultaneous quantification method of six corticosteroids, cortisone, cortisol, cortexolone, corticosterone, dehydrocorticosterone and deoxycorticosterone, by LC-electrospray ionization (ESI)-MS in a positive mode using novel picolinoyl derivatization was investigated. Conversion of each corticosteroid into the corresponding picolinoyl derivative was performed by mixed anhydride method using picolinic acids and 2-methyl-6-nitrobenzoic anhydride. Derivatization proceeded smoothly to afford the corresponding 21-monopicolinoyl derivatives. Positive ion-ESI mass spectra of the picolinoyl derivatives were dominated by the appearance of M+H as base peaks. The picolinoyl derivatives provided 5-10 times higher ESI response in the LC-ESI-MS-selected reaction monitoring (SRM) when compared to those of underivatized molecules in a positive LC-ESI-MS mode. The use of the picolinoyl ester, solid-phase extraction, and deuterium labeled internal standards enabled to determine the concentrations of these corticosteroids in human saliva simultaneously by LC-ESI-MS-SRM.
研究了一种采用新型吡啶甲酰基衍生化的液相色谱-电喷雾电离（ESI）-质谱正模式同时定量测定六种皮质类固醇（可的松、皮质醇、皮质素、皮质酮、脱氢皮质酮和脱氧皮质酮）的方法。通过使用吡啶甲酸和2-甲基-6-硝基苯甲酸酐的混合酸酐法，将每种皮质类固醇转化为相应的吡啶甲酰基衍生物。衍生化反应顺利进行，得到相应的21-单吡啶甲酰基衍生物。吡啶甲酰基衍生物的正离子-ESI质谱以M+H作为基峰出现为主。与正模式液相色谱-电喷雾电离质谱中未衍生化分子相比，吡啶甲酰基衍生物在液相色谱-电喷雾电离质谱选择反应监测（SRM）中提供的ESI响应高5-10倍。使用吡啶甲酰基酯、固相萃取和氘标记内标，能够通过液相色谱-电喷雾电离质谱-SRM同时测定人唾液中这些皮质类固醇的浓度。
