Holtkamp Hannah U, Morrow Stuart J, Kubanik Mario, Hartinger Christian G
School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
J Biol Inorg Chem. 2017 Jul;22(5):789-798. doi: 10.1007/s00775-016-1426-z. Epub 2017 Jan 2.
Run-by-run variations are very common in capillary electrophoretic (CE) separations and cause imprecision in both the migration times and the peak areas. This makes peak and kinetic trend identification difficult and error prone. With the aim to identify suitable standards for CE separations which are compatible with the common detectors UV, ESI-MS, and ICP-MS, the Co complexes [Co(en)]Cl, [Co(acac)] and K[Co(EDTA)] were evaluated as internal standards in the reaction of the anticancer drug cisplatin and guanosine 5'-monophosphate as an example of a classical biological inorganic chemistry experiment. These Co chelate complexes were considered for their stability, accessibility, and the low detection limit for Co in ICP-MS. Furthermore, the Co complexes are positively and negatively charged as well as neutral, allowing the detection in different areas of the electropherograms. The background electrolytes were chosen to cover a wide pH range. The compatibility to the separation conditions was dependent on the ligands attached to the Co centers, with only the acetylacetonato (acac) complex being applicable in the pH range 2.8-9.0. Furthermore, because of being charge neutral, this compound could be used as an electroosmotic flow (EOF) marker. In general, employing Co complexes resulted in improved data sets, particularly with regard to the migration times and peak areas, which resulted, for example, in higher linear ranges for the quantification of cisplatin.
逐次运行变化在毛细管电泳（CE）分离中非常常见，会导致迁移时间和峰面积出现不精确性。这使得峰和动力学趋势的识别变得困难且容易出错。为了确定适用于CE分离且与常见检测器紫外（UV）、电喷雾电离质谱（ESI-MS）和电感耦合等离子体质谱（ICP-MS）兼容的标准物，以抗癌药物顺铂与5'-单磷酸鸟苷的反应为例，对钴配合物[Co(en)]Cl、[Co(acac)]和K[Co(EDTA)]作为内标进行了评估，这是一个经典的生物无机化学实验。考虑这些钴螯合物是因其稳定性、可获取性以及ICP-MS中钴的低检测限。此外，这些钴配合物带有正电荷、负电荷以及呈中性，能够在电泳图的不同区域进行检测。选择背景电解质以覆盖较宽的pH范围。与分离条件的兼容性取决于连接在钴中心的配体，只有乙酰丙酮（acac）配合物适用于2.8 - 9.0的pH范围。此外，由于呈电中性，该化合物可用作电渗流（EOF）标记物。总体而言，使用钴配合物可得到改进的数据集，特别是在迁移时间和峰面积方面，例如，这导致顺铂定量的线性范围更高。
