FIA Laboratory, Analytical Chemistry Section, INQUISUR (UNS-CONICET), Bahía Blanca, Buenos Aires, Argentina.
Electrophoresis. 2012 Jul;33(13):2049-55. doi: 10.1002/elps.201100713.
A method to determine four antibiotics for veterinary use (ciprofloxacin, enrofloxacin, florfenicol, and chloramphenicol) of different families (fluoroquinolones and amphenicols) in bovine milk was developed. The determination of the analytes was carried out using micellar electrokinetic capillary chromatography (MEKC) with a common sodium borate-SDS buffer solution containing single-walled carbon nanotubes (SWCNTs). In this way, a great improvement in the electrophoretic resolution and the separation efficiency was achieved compared to MEKC. An online reverse electrode polarity-stacking mode (REPSM) was carried out to enhance sensitivity. This step was performed in only 2 min and it allowed a stacked percentage of 103. That means that all the amount of injected analytes is effectively stacked. When this stacking procedure was combined with an off-line preconcentration step, based on SPE, analytes could be detected in lower concentration than the established maximum residue limits (MRLs). The LODs for the four compounds were between 6.8 and 13.8 μg L(-1) and the RSD values were between 1.1% and 6.6%. The whole method was applied to spiked real samples with acceptable precision and satisfactory recoveries.
建立了一种测定牛奶中 4 种不同类型（氟喹诺酮类和酰胺醇类）兽用抗生素（环丙沙星、恩诺沙星、氟苯尼考和氯霉素）的方法。采用含有单壁碳纳米管（SWCNTs）的普通硼酸钠-SDS 缓冲溶液进行胶束电动毛细管色谱（MEKC）分析来测定分析物。与 MEKC 相比，这种方法大大提高了电泳分辨率和分离效率。采用在线反电极极性堆积模式（REPSM）提高了灵敏度。该步骤仅需 2 分钟即可完成，可实现 103%的堆积效率。这意味着注入的所有分析物都能有效堆积。当将这种堆积程序与基于 SPE 的离线浓缩步骤结合使用时，分析物可以在低于规定的最大残留限量（MRL）的浓度下进行检测。四种化合物的检出限（LOD）在 6.8 至 13.8 μg/L 之间，相对标准偏差（RSD）在 1.1%至 6.6%之间。该方法可应用于加标实际样品，具有可接受的精密度和令人满意的回收率。
