Wrobel Kazimierz, Wrobel Katarzyna, Kannamkumarath Sasi S, Caruso Joseph A
Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172, USA.
Anal Bioanal Chem. 2003 Oct;377(4):670-4. doi: 10.1007/s00216-003-2147-z. Epub 2003 Aug 23.
This study focused on the detection/identification of possible selenium metabolites in human urine. Organoselenium compounds not commercially unavailable were synthesized and characterized by electrospray mass spectrometry. Separation of selenomethionine, methylselenomethionine, trimethylselonium, selenoethionine, and selenoadenosylmethionine was achieved by ion-pairing HPLC with a mobile phase of 2 mmol L(-1) hexanesulfonic acid, 0.4% acetic acid, 0.2% triethanolamine (pH 2.5), and 5% methanol. The column effluent was introduced on-line to inductively coupled plasma-mass spectrometry for selenium-specific detection ((77)Se and (78)Se). For selenium speciation in urine, solid-phase extraction was carried out using C(18) cartridges modified with hexanesulfonic acid. Selective retention of cationic species was observed from acidified urine (perchloric acid, pH 2.0). After elution with methanol, evaporation, and dissolution in the mobile phase, the sample was introduced to the HPLC-ICP-MS system and the chromatographic peaks were assigned by adding standards. The species identified in urine were selenomethionine, trimethylselonium ion, and selenoadenosylmethionine. The last species was detected for the first time and our results suggest that selenomethionine might enter the metabolic pathway of its sulfur analog in the activated methylation cycle.
本研究聚焦于人体尿液中可能存在的硒代谢产物的检测/鉴定。合成了非市售的有机硒化合物，并通过电喷雾质谱对其进行了表征。通过离子对高效液相色谱法，以2 mmol L(-1)己烷磺酸、0.4%乙酸、0.2%三乙醇胺（pH 2.5）和5%甲醇的流动相实现了硒代蛋氨酸、甲基硒代蛋氨酸、三甲基硒离子、硒代乙硫氨酸和硒代腺苷甲硫氨酸的分离。将柱流出物在线引入电感耦合等离子体质谱仪进行硒特异性检测（(77)Se和(78)Se）。对于尿液中的硒形态分析，使用用己烷磺酸改性的C(18)柱进行固相萃取。在酸化尿液（高氯酸，pH 2.0）中观察到阳离子物种的选择性保留。用甲醇洗脱、蒸发并溶解于流动相后，将样品引入高效液相色谱-电感耦合等离子体质谱系统，并通过添加标准品对色谱峰进行归属。在尿液中鉴定出硒代蛋氨酸、三甲基硒离子和硒代腺苷甲硫氨酸。最后一种物种是首次检测到，我们的结果表明硒代蛋氨酸可能在活化甲基化循环中进入其硫类似物的代谢途径。
