固相微萃取-多毛细管柱-离子迁移谱法（SPME–MCC–IMS）检测番茄叶中水杨酸甲酯

Solid Phase Microextraction–Multicapillary Column–Ion Mobility Spectrometry (SPME–MCC–IMS) for Detection of Methyl Salicylate in Tomato Leaves

固相微萃取-多毛细管柱-离子迁移谱法（SPME–MCC–IMS）检测番茄叶中水杨酸甲酯

Abstract

Methyl salicylate (MeSA) is a plant-signaling molecule that plays an essential role in the regulation of plant responses to biotic and abiotic pathogens. In this work, solid phase microextraction (SPME) and a multicapillary column (MCC) are coupled to ion mobility spectrometry (IMS) to detect MeSA in tomato leaves. The SPME–MCC–IMS method provides two-dimensional (2D) separation by both MCC and IMS, based on the retention and drift times. The effect of the IMS polarity on the separation efficiency of MCCs was also investigated. In the positive polarity, ionization of MeSA resulted in [MeSA + H]+ formation while, in the negative, deprotonated ions, [MeSA – H]−, and the O2– adduct ion, [MeSA + O2]−, were formed. In the real sample analysis, the negative polarity operation resulted in the suppression of many matrix molecules and thus in the reduction of interferences. Four different SPME fibers were used for head space analysis, and four MCC columns were investigated. In the negative polarity, complete separation was achieved for all of the MCCs columns. The limits of detection (LODs) of 0.1 μg mL–1 and linear range of 0.25–12 μg mL–1 were obtained for the measurement of MeSA in a standard solution (H2O/CH3OH, 50:50) by the SPME–IMS method with a 5 min extraction time using an SPME with a PDMS fiber, in the negative mode of IMS. The MeSA contents of fresh tomato leaves were determined as 1.5–9.8 μg g–1, 24–96 h after inoculation by tomato mosaic ringspot virus (ToRSV).

水杨酸甲酯（MeSA）是一种植物信号分子，在调节植物对生物和非生物病原体的反应中起着重要作用。在这项工作中，固相微萃取（SPME）和多毛细管柱（MCC）与离子迁移谱法（IMS）相结合，以检测番茄叶片中的MeSA。SPME–MCC–IMS方法基于保留时间和漂移时间，通过MCC和IMS提供二维（2D）分离。还研究了IMS极性对MCC分离效率的影响。在正极性中，MeSA的电离导致[MeSA+H]+的形成，而在负极性中，形成去质子化离子[MeSA–H]−和O2-加合离子[MeSA+O2]−。在实际样品分析中，负极性操作导致了许多基质分子的抑制，从而减少了干扰。四种不同的SPME纤维用于顶空分析，并研究了四种MCC柱。在负极性下，所有MCC柱都实现了完全分离。在IMS的负模式下，使用SPME–IMS方法在5分钟提取时间内测量标准溶液（H2O/CH3OH，50:50）中的MeSA，检测限（LOD）为0.1μg mL^-1，线性范围为0.25–12μg mL^-1。在接种番茄花叶病毒环斑病毒（ToRSV）后24–96小时，新鲜番茄叶片的MeSA含量测定为1.5–9.8μg g^–1。

KEYWORDS:solid phase microextraction multicapillary column ion mobility spectrometry methyl salicylate tomato leaves

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