Tang Zhentao, Duan Yixiang
Research Center of Analytical Instrumentation, Analytical & Testing Center, Sichuan University, Chengdu 610065, China.
Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
Talanta. 2017 Sep 1;172:45-52. doi: 10.1016/j.talanta.2017.05.032. Epub 2017 May 11.
A kind of porous ionic liquid polymer was designed as coating material for solid-phase microextraction (SPME) fibers to extract polar organic acids. The synthesized ionic liquids (1-vinyl-3-(4-vinyl-benzyl)imidazolium chloride) were polymerized in the presence of azobisisobutyronitrile (AIBN), and subsequently coated on stainless steel wires with physical adhesion. To guarantee the adhesion between coating and the surface of stainless steel wires, micro-wave induced plasma was applied to modify the stainless steel wires. The derivatives of extracted organic acids were analyzed by gas chromatography combined with mass spectrometry (GC-MS) with N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) as the derivatization reagent. Under the optimal condition, a calibration study was carried out to evaluate the performance of the SPME fibers. The calibration curves were linear (R>0.99) in the range from 0.01μg/ml to 1μg/ml for six organic acids. Detection limits were detected down to 0.07ng/ml. To further validate the extraction efficiency of the fibers, experiments were conducted in comparison with commercial fibers. Lower LOD and LOQ values were obtained by the in-house fabricated fibers especially for polyatomic acids. Good repeatability (RSD≤16%) and fiber-to-fiber reproducibility (RSD≤20%) were obtained. The acceptable recovery of the spiked grape wine samples ranged from 78.19% to 98.11%. Additionally, long lifetime and good durability of the fibers have been demonstrated. The performance of the established SPME-GC-MS method for analysis of organic acids was shown to be greatly improved in comparison to the direct HPLC/CE method or other SPME materials as reported in the literature. In summary, a feasible and effective approach has been demonstrated to fabricate the in-house fabricated fibers based on porous ionic liquid polymers, which were proved to be advantageous and sensitive for extraction of polar organic acids. Simultaneously, application of the SPME derivatization GC-MS method for analysis of organic acids has been successfully verified as feasible and reliable.
一种多孔离子液体聚合物被设计用作固相微萃取（SPME）纤维的涂层材料，用于萃取极性有机酸。合成的离子液体（1-乙烯基-3-(4-乙烯基苄基)咪唑氯盐）在偶氮二异丁腈（AIBN）存在下聚合，随后通过物理附着涂覆在不锈钢丝上。为确保涂层与不锈钢丝表面之间的附着力，采用微波诱导等离子体对不锈钢丝进行改性。萃取的有机酸衍生物采用气相色谱-质谱联用（GC-MS）分析，以N-叔丁基二甲基硅基-N-甲基三氟乙酰胺（MTBSTFA）作为衍生化试剂。在最佳条件下，进行了校准研究以评估SPME纤维的性能。六种有机酸的校准曲线在0.01μg/ml至1μg/ml范围内呈线性（R>0.99）。检测限低至0.07ng/ml。为进一步验证纤维的萃取效率，与商用纤维进行了对比实验。自制纤维获得了更低的检测限和定量限，尤其是对于多元酸。具有良好的重复性（RSD≤16%）和纤维间重现性（RSD≤20%）。加标葡萄酒样品的回收率在78.19%至98.11%之间。此外，已证明纤维具有长寿命和良好的耐用性。与直接HPLC/CE方法或文献报道的其他SPME材料相比，所建立的用于分析有机酸的SPME-GC-MS方法的性能有了显著提高。总之，已证明一种基于多孔离子液体聚合物制备自制纤维的可行且有效的方法，该方法被证明对于萃取极性有机酸具有优势且灵敏。同时，成功验证了SPME衍生化GC-MS方法用于分析有机酸是可行且可靠的。
