Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Chromatogr A. 2010 Dec 3;1217(49):7807-11. doi: 10.1016/j.chroma.2010.10.041. Epub 2010 Oct 14.
An integrative coupling method of headspace liquid-phase microextraction (HS-LPME) and capillary zone electrophoresis (CZE) was proposed in this paper. In the method, a separation capillary was used to create a microextraction droplet of the running buffer solution of CZE, hold the droplet at the capillary inlet, extract analytes of sample solutions in the headspace of a sample vial, inject concentrated analytes into the capillary and separate the analytes by CZE. The proposed method was applied to determine the preservatives of benzoic acid and sorbic acid in soy sauce and soft drink samples, in which the running buffer solution of 50 mmol/L tetraborate (pH 9.2) was directly used to form the acceptor droplet at the capillary inlet by pressure, and the preservatives in a 6-mL sample solution containing 0.25 g/mL NaCl were extracted at 90°C for 30 min in the headspace of a 14-mL sample vial. Then the concentrated preservatives were injected into the capillary at 10 cm height difference for 20 s and separated by CZE. The enrichment factors of benzoic acid and sorbic acid achieved 266 and 404, and the limits of detection (LODs) were 0.03 and 0.01 μg/mL (S/N=3), respectively. The recoveries were in the range of 88.7-105%. The integrative coupling method of HS-LPME and CZE was simple, convenient, reliable and suitable for concentrating volatile and semi-volatile organic acids and eliminating matrix interferences of real samples.
本文提出了一种顶空液相微萃取（HS-LPME）和毛细管区带电泳（CZE）的集成偶联方法。在该方法中，使用分离毛细管在 CZE 的运行缓冲溶液中形成微萃取液滴，将液滴保持在毛细管入口处，从样品瓶的顶空部分萃取样品溶液中的分析物，将浓缩的分析物注入毛细管中，并通过 CZE 分离分析物。该方法用于测定酱油和软饮料样品中苯甲酸和山梨酸的防腐剂，其中直接使用 50mmol/L 四硼酸盐（pH9.2）的运行缓冲溶液通过压力在毛细管入口处形成接受液滴，并且在 90°C 下，在含有 0.25g/mL NaCl 的 6mL 样品溶液的顶空部分中萃取 30min。然后，将浓缩的防腐剂在 10cm 高度差下注入毛细管中，并通过 CZE 进行分离。苯甲酸和山梨酸的富集因子分别达到 266 和 404，检测限（LOD）分别为 0.03 和 0.01μg/mL（S/N=3）。回收率在 88.7-105%之间。HS-LPME 和 CZE 的集成偶联方法简单、方便、可靠，适用于浓缩挥发性和半挥发性有机酸，并消除实际样品的基质干扰。
