A simple and sensitive preconcentration strategy using sequential electrokinetic and hydrodynamic injection modes in micellar electrokinetic chromatography with diode array detection was developed and applied for the separation and determination of anticancer agent, 5‐fluorouracil and its metabolite, 5‐fluoro‐2′‐deoxyuridine, in human plasma. Sequential injection modes with increased analyte loading capacity using the anionic pseudo‐stationary phase facilitated collection of the dispersed neutral and charged analytes into narrow zones and improved sensitivity. Several important parameters affecting sample enrichment performance were evaluated and optimized in this study. Under the optimized experimental conditions, 614‐ and 643‐fold and 782‐ and 803‐fold sensitivity improvement were obtained for 5‐fluorouracil and its metabolite when compared with normal hydrodynamic and electrokinetic injection, respectively. The method has good linearity (1–1,000 ng/ml) with acceptable coefficient of determination (r² > 0.993), low limits of detection (0.11–0.14 ng/ml) and satisfactory analyte relative recovery (97.4–99.7%) with relative standard deviations of 4.6–9.3% (n = 6). Validation results as well as the application to analysis of human plasma samples from cancer patients demonstrate the applicability of the proposed method to clinical studies.

中文翻译：

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胶束电动色谱法中一种简单有效的连续电动和流体动力注射定量人体血浆中的抗癌药5-氟尿嘧啶及其代谢产物

开发了一种简单且灵敏的预浓缩策略，该方法在带二极管阵列检测的胶束电动色谱中采用顺序电动和流体动力进样方式进行了开发，并将其用于抗癌剂5-氟尿嘧啶及其代谢产物5-氟-2'-脱氧尿苷的分离和测定，在人类血浆中。使用阴离子伪平稳相的顺序进样模式具有更高的分析物上样能力，有助于将分散的中性和带电分析物收集到狭窄区域，并提高了灵敏度。在这项研究中，对影响样品富集性能的几个重要参数进行了评估和优化。在优化的实验条件下，与正常的流体动力注射和电动注射相比，5-氟尿嘧啶及其代谢物的灵敏度分别提高了614和643倍，以及782和803倍。该方法具有良好的线性（1-1,000 ng / ml），测定系数可以接受（r ²  > 0.993），低检出限（0.11-0.14 ng / ml）和令人满意的分析物相对回收率（97.4-99.7％），相对标准偏差为4.6-9.3％（n = 6）。验证结果以及对癌症患者血浆样品分析的应用证明了该方法在临床研究中的适用性。