Institute of Mass Spectrometry, School of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China; Department of Chemistry, Fudan University, Shanghai 200438, China.
Department of Chemistry, Fudan University, Shanghai 200438, China.
Talanta. 2019 Jun 1;198:118-127. doi: 10.1016/j.talanta.2019.01.073. Epub 2019 Jan 25.
Herein, we realized the simultaneous online detection of six tobacco alkaloids (TAs) by in-tube solid-phase microextraction (In-tube SPME) coupled with mass spectrometry by a rapid, sensitive, and matrix effect-free method requiring no chromatographic separation and only minimal sample pre-treatment. A poly (N-isopropylacrylamide-co-divinylbenzene-co-N, N'-methylenediacrylamide) [Poly (NIPAAm-co-DVB-co-MBAA)] monolithic column was designed according to the chemical structures of selected TAs and used as an extraction medium engaging in hydrophobic, π-π, and hydrogen bonding interactions with analytes, allowing them to be effectively extracted. A number of important parameters were systematically optimized to achieve maximal extraction efficiency. The ion intensity of the TAs signals obtained by in-tube SPME-MS were higher than the direct MS mode by about 400 folds with the signal-to-noise ratio improved by 2-7 folds. The detection limits of the six TAs were determined as 1.99-4.06 ng g, with good linearity with correlation coefficients exceeding 0.99 obtained under optimal extraction conditions. Besides, TA recoveries in cigarette tobacco spiked at three concentration levels were in the range of 76.4-100.2%, and the corresponding RSDs (n = 5) were obtained as 4.32-7.16%. The extraction performance of the poly (NIPAAm-co-DVB-co-MBAA) monolithic column was well reproducible, with intra- or inter-day precision RSDs determined not to exceed 7.38%. Finally, no marked matrix effects were observed when the developed method was applied to the analysis of both high-abundance and trace-level TAs in practical samples, and the above technique was therefore concluded to be well suited for the detection of TAs in cigarette tobacco or other products.
本文通过一种快速、灵敏且无基质效应的方法，实现了同时在线检测六种烟草生物碱（TAs），无需色谱分离且仅需最小的样品预处理。根据所选 TAs 的化学结构设计了一种聚（N-异丙基丙烯酰胺-co-二乙烯基苯-co-N，N'-亚甲基双丙烯酰胺）[聚（NIPAAm-co-DVB-co-MBAA）]整体柱，并用作与分析物发生疏水、π-π 和氢键相互作用的萃取介质，使其能够被有效萃取。系统地优化了许多重要参数以实现最大的萃取效率。通过内管固相微萃取-MS 获得的 TAs 信号的离子强度比直接 MS 模式高约 400 倍，信噪比提高了 2-7 倍。在最佳萃取条件下，六种 TAs 的检测限确定为 1.99-4.06 ng/g，具有良好的线性关系，相关系数均超过 0.99。此外，在三个浓度水平下对香烟烟草进行加标回收实验，TAs 的回收率在 76.4-100.2%范围内，相应的 RSD（n=5）为 4.32-7.16%。聚（NIPAAm-co-DVB-co-MBAA）整体柱的萃取性能具有良好的重现性，日内或日间精密度 RSD 不超过 7.38%。最后，当将所开发的方法应用于实际样品中高丰度和痕量 TAs 的分析时，未观察到明显的基质效应，因此该技术非常适合于香烟烟草或其他产品中 TAs 的检测。
