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首页> 外文期刊>American Journal of Analytical Chemistry >Mixed Micellar Electrokinetic Chromatographic Analysis of Colistin, Polypeptide Antibiotic, Using Laser-Induced Fluorescence Detection
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Mixed Micellar Electrokinetic Chromatographic Analysis of Colistin, Polypeptide Antibiotic, Using Laser-Induced Fluorescence Detection

机译：激光诱导荧光检测共肽，多肽抗生素的混合胶束电动色谱分析

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The main goal of this work was to quantify the detection of colistin at low levels in urine samples through the practical application of mixed surfactant micellar electrokinetic chromatography–laser-induced fluorescence (MEKC-LIF) analysis method using its advantage of sensitivity and to examine direct injection of biological samples. Colistin (po- lymyxin E) has neither strong UV chromophore nor fluorophore. So, its assay for metabolism, pharmacokinetics studies for bioavailability and bioequivalence are difficult because of poor detectability. Therefore an enhanced UV or fluores-cence detection by chemical derivatization is required. MEKC-LIF method was proposed for colistin with a 488/520 nm argon-ion laser using a pre-CE derivatization with fluorescein isothiocyanate (FITC). Borate buffer was used as background buffer (BGB). The different parameters affecting the proposed derivatization reaction including concentration of the derivatizing reagent, reaction time and temperature were studied and optimized. The derivative was stable for up to 3 days. Different micelles (TX-100 and SDS) were examined as BGB additives separately but negative-charged mixed micelles (SDS/TX-100) were shown to be the best additive to BGB for the analysis of colistin particularly in human urine as they enhance both selectivity and sensitivity of the proposed method. BGB was used with pH 9.5, 10 kV, 8 s inj time, capillary length 75 cm × 75 μm ID (66 cm effective length), detection was LIF Ex 488 nm; Em 520 nm. The method was applied to colistin analysis in human urine and the recovery was > 98% (n = 5). LOD and LOQ in urine after pre-column derivatization using FITC were 100 and 250 ng/ml, respectively. Urine samples were analysed by direct injection without sample pre-treatment. The mechanism of enhancement of fluorescence of the derivative by surfactant was proposed.
机译：这项工作的主要目标是通过混合表面活性剂胶束电动色谱-激光诱导荧光（MEKC-LIF）分析方法的实际应用，利用尿液中大肠杆菌素的敏感性优势，对尿液中的低粘菌素进行定量检测，并直接检测进样生物样品。共利斯汀（多粘菌素E）既不具有强紫外线发色团，也没有荧光团。因此，由于可检测性差，因此难以进行代谢测定，生物利用度和生物等效性的药代动力学研究。因此，需要通过化学衍生化来增强UV或荧光检测。有人提出将MEKC-LIF方法用于488/520 nm氩离子激光器的大肠菌素，并使用异硫氰酸荧光素（FITC）进行CE衍生化。硼酸盐缓冲液用作背景缓冲液（BGB）。研究和优化了影响拟议的衍生化反应的不同参数，包括衍生化试剂的浓度，反应时间和温度。衍生物稳定长达3天。分别检查了不同的胶束（TX-100和SDS）作为BGB添加剂，但负电荷混合胶束（SDS / TX-100）被证明是BGB最好的胶粘素分析添加剂，特别是在人类尿液中，因为它们同时增强了BGB所提方法的选择性和灵敏度。使用BGB，pH 9.5，10 kV，注入时间8 s，毛细管长度75 cm×75μmID（有效长度66 cm），检测为LIF Ex 488 nm; Em 520 nm。该方法用于人尿中粘菌素的分析，回收率> 98％（n = 5）。使用FITC进行柱前衍生后，尿液中的LOD和LOQ分别为100 ng / ml和250 ng / ml。通过直接进样对尿液样品进行分析，而无需样品预处理。提出了表面活性剂增强衍生物荧光的机理。

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