Mikus Peter, Maráková Katarína, Veizerová Lucia, Piestansky Juraj, Galba Jaroslav, Havránek Emil
Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University in Bratislava, Slovak Republic.
J Chromatogr Sci. 2012 Nov-Dec;50(10):849-54. doi: 10.1093/chromsci/bms083. Epub 2012 Jun 7.
The possibilities of a column coupling two-dimensional capillary electrophoresis (2D CE) combined with fiber-based diode array detection (DAD) for the direct, highly reliable and ultrasensitive quantitative determination of quinine in real multicomponent ionic matrices (human urine) are demonstrated in this work. The capillary isotachophoresis (CITP) stage provided an on-line sample pretreatment (elimination of interfering matrix constituents, preseparation and preconcentration of the analyte) before the capillary zone electrophoresis (CZE) separation. Due to the large volume (30 µL) sample injection and CITP sample preconcentration, a simple absorbance photometric detection was sufficient for obtaining very low concentration limits of detection (∼8.6 ng/mL). The combination of the different separation mechanisms (CITP and CZE) resulted in enhanced separation selectivity. This enabled us to obtain a pure analyte zone in the directly injected real samples suitable for qualitative and quantitative evaluation. The spectral DAD allowed (i) characterization of the purity (i.e., spectral homogeneity) of the analyte zone; and (ii) preliminary indication of structurally related compounds (i.e., potential biodegradation products of quinine), via characteristic spectra recorded in intervals of 200-800 nm. The CITP-CZE-DAD method was characterized by favorable performance parameters that are suitable for its routine biomedical use. One of the primary benefits of the CITP-CZE-DAD method is the possibility of performing direct injections of real biological samples while avoiding external sample preparation procedures and, therefore, enhancing the reliability and applicability of analyses and the potential for method automatization and miniaturization.
本文展示了柱耦合二维毛细管电泳（2D CE）与基于光纤的二极管阵列检测（DAD）相结合，用于在实际多组分离子基质（人尿）中直接、高度可靠且超灵敏定量测定奎宁的可能性。毛细管等速电泳（CITP）阶段在毛细管区带电泳（CZE）分离之前提供了在线样品预处理（消除干扰基质成分、预分离和预富集分析物）。由于大体积（30 μL）进样和CITP样品预富集，简单的吸光度光度检测就足以获得非常低的检测限（约8.6 ng/mL）。不同分离机制（CITP和CZE）的结合提高了分离选择性。这使我们能够在直接进样的实际样品中获得适合定性和定量评估的纯分析物区带。光谱DAD允许（i）表征分析物区带的纯度（即光谱均匀性）；以及（ii）通过在200 - 800 nm区间记录的特征光谱初步指示结构相关化合物（即奎宁的潜在生物降解产物）。CITP - CZE - DAD方法具有适合其常规生物医学应用的良好性能参数。CITP - CZE - DAD方法的主要优点之一是能够直接进样实际生物样品，同时避免外部样品制备程序，从而提高分析的可靠性和适用性以及方法自动化和小型化的潜力。
