Enantiomeric separation of chiral dipeptides by CE-ESI-MS employing a partial filling technique with chiral crown ether
Enantiomeric separation of chiral dipeptides by CE-ESI-MS employing a partial filling technique with chiral crown ether
复制标题
采用手性冠醚部分填充技术，通过 CE-ESI-MS 分离手性二肽的对映体
DOI：
10.1002/elps.200800799
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发表时间：
2009-08-01
期刊：
影响因子：
2.9
通讯作者：
Chen, Guonan
中科院分区：
文献类型：
--
作者：
Xia, Shifei;Zhang, Lan;Chen, Guonan
以(+)-(18-冠-6)-2,3,11,12-四羧酸(18C（6)H(4)）为手性选择剂，采用CE-ESI-MS在裸熔融石英毛细管中分离了手性二肽对映体。由于18C(6)H(4)是一种非挥发性手性选择剂，为了防止18C(6)H(4)进入CE-ESI-MS离子源，本研究采用部分填充技术。采用单手性中心或双手性中心二肽DL-Leu-DL-Leu、D-Ala-D-Ala和L-Ala-L-Ala、Gly-D-Phe和Gly-L-Phe进行CE-ESI-MS体系评价。以2.0 mol/L （pH 2.15）的乙酸为运行电解质，在进样前以3.0 mol/L （pH 2.00）的乙酸溶液中注入5 mM 18C(6)H(4) （50 mbar，持续960 s）。护套液采用80% v/v的甲醇-水溶液，共7.5 mM乙酸，外加电压20 kV。在最佳条件下，对这些二肽进行了分离和检测。该方法对D-Ala-D-Ala、L- ala -L- ala、DL-LeU-DL-Leu、Gly-L-Phe和Gly-D-Phe的lod（定义为S/N = 3）分别为0.20、0.10、0.05和0.10 μ mol/L。迁移次数和峰面积的rsd分别为0.68 ~ 2.08%和2.32 ~ 5.24% （n = 7）。该方法还成功地应用于加标血清样品中这些二肽的对映选择分析，结果令人满意。
Enantiomer of chiral dipeptides were separated by CE-ESI-MS in a bare fused-silica capillary using (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18C(6)H(4)) as the chiral selector. As 18C(6)H(4) is a kind of nonvolatile chiral selector, in order to prevent from 18C(6)H(4) into the ion-source of CE-ESI-MS, a partial filling technique was employed in this study. Some dipeptides with one chiral center or two chiral centers, such as DL-Leu-DL-Leu, D-Ala-D-Ala and L-Ala-L-Ala, Gly-D-Phe and Gly-L-Phe were used to evaluate this CE-ESI-MS system. Optimized conditions were achivevd with 2.0 mol/L acetic acid (pH 2.15) as the running electrolyte, 5 mM 18C(6)H(4) in 3.0 mol/L acetic acid (pH 2.00) was injected hydrodynamically (50 mbar for 960 s) before sample injection. In total 7.5 mM acetic acid in 80% v/v methanol-water was used as the sheath liquid, and 20 kV applied voltage was used. Under the optimum conditions, these dipeptides were separated and detected. LODs (defined as S/N = 3) of this method were 0.20, 0.10, 0.05 and 0.10 mu mol/L for D-Ala-D-Ala, L-Ala-L-Ala, DL-LeU-DL-Leu, Gly-L-Phe and Gly-D-Phe, respectively. The RSDs (n = 7) of the method were 0.68-2.08% for migration times and 2.32-5.24% for peak areas. The proposed method was also successfully applied to the enantioselective analysis of these dipeptides in the spiked serum samples with satisfactory results.