Enantioseparation and stacking of cyanobenz[f]isoindole-amino acids by reverse polarity capillary electrophoresis and sulfated β-cyclodextrin
Enantioseparation and stacking of cyanobenz[f]isoindole-amino acids by reverse polarity capillary electrophoresis and sulfated β-cyclodextrin
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DOI：
10.1021/ac061725
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发表时间：
2007-01-15
影响因子：
7.4
通讯作者：
Green, Thomas K.
中科院分区：
文献类型：
--
作者：
Kirschner, Daniel L.;Jaramillo, Michael;Green, Thomas K.
建立并优化了毛细管电泳法分离氰基苯并[f]异吲哚(CBI)氨基酸衍生物的激光诱导荧光检测方法。以S-β-CD为手性选择剂，在低pH和反极性条件下完成了对映体的拆分。对CBI-丝氨酸的BGE条件进行了优化，并将其应用于其他CBI-氨基酸。以2wt%S-β-环糊精为底物，在25 mm磷酸盐缓冲液中，pH 2.00，-30kV的电压下，实现了13种氨基酸的基线拆分。PH值是影响分辨率的最关键的BGE参数。在2wt%的S-β-环糊精溶液中，CbI-丝氨酸对映体在pH为2.00时得到基线拆分，而在pH为3.00时无拆分。为了说明L-谷氨酸、L-天冬氨酸和D-丝氨酸在生物样品中的应用，同时测定了北极黄鼠微透析液中谷氨酸、L-天冬氨酸和D-丝氨酸的含量。CBI-氨基酸在水中的稀溶液可以通过流体动力注射堆积，信噪比提高100倍而不会损失手性拆分。堆积过程由场放大运移、pH介导的堆积和S-β-CD的扫掠三部分组成。CBI-DL-丝氨酸和CBI-DL-谷氨酸的检出限分别为0.20和0.30 nm。堆积法不适用于高离子强度的微透析液。
A capillary electrophoresis method with laser-induced fluorescence detection for the chiral separation of cyanobenz[f] isoindole ( CBI) derivatives of amino acids was developed and optimized. The enantioseparations are accomplished with sulfated beta-CD (S-beta-CD) as chiral selector at low pH and reverse polarity. BGE conditions were optimized for CBI-serine and then applied to other CBI-amino acids. Baseline resolution of 13 CBI-amino acids was achieved using a single BGE formulation of 2 wt % S-beta-CD in 25 mM phosphate buffer at pH 2.00 and a voltage of - 30 kV. pH is the most critical BGE parameter affecting resolution. At 2 wt % S-beta-CD, CBI-serine enantiomers are baseline-resolved at pH 2.00 but no resolution is obtained at pH 3.00. L-Glutamate, L-aspartate and D-serine are simultaneously quantified in the microdialysate of an arctic ground squirrel to illustrate the application to biological samples. Dilute solutions of the CBI-amino acids in water can be stacked by hydrodynamic injection with a 100-fold improvement in signal-to-noise ratio without loss of chiral resolution. The stacking is proposed to consist of field-amplified migration, pH-mediated stacking, and sweeping by S-beta-CD. The limit of detections for CBI-DL-serine and CBI-DL-glutamate are determined as 0.20 and 0.30 nM, respectively. The stacking method was not applicable to the high ionic strength microdialysates.