Mass spectrometry (MS) has revolutionized analytical chemistry, enabling precise identification and quantification of chemical species, which is pivotal for biomarker discovery and understanding complex biological systems. Despite its versatility, the presence of background ions in MS analysis hinders the sensitive detection of low‐abundance analytes. Therefore, studies aimed at lowering background ion levels have become increasingly important. Here, we utilized the commercially available Active Background Ion Reduction Device (ABIRD) to suppress background ions and assess its effect on the liquid chromatography–electrospray ionization (LC–ESI)–MS analyses of N‐glycans on the Q Exactive HF mass spectrometer. We also investigated the effect of different solvent vapors in the ESI source on N‐glycan analysis by MS. ABIRD generally had no effect on high‐mannose and neutral structures but reduced the intensity of some structures that contained sialic acid, fucose, or both when methanol vapor filled the ESI source. Based on our findings on the highest number of identified N‐glycans from human serum, methanol vapor in the ion source compartment may enhance N‐glycan LC–ESI–MS analyses by improving the desolvation of droplets formed during the ESI process due to its high volatility. This protocol may be further validated and extended to advanced bottom‐up proteomic/glycoproteomic studies for the analysis of peptide/glycopeptide ions by MS.

中文翻译：

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使用活性背景离子还原装置抑制全甲基化聚糖的 LC-ESI-MS 分析的背景

质谱 (MS) 彻底改变了分析化学，能够精确识别和定量化学物质，这对于生物标志物发现和理解复杂生物系统至关重要。尽管其用途广泛，但 MS 分析中背景离子的存在阻碍了低丰度分析物的灵敏检测。因此，旨在降低背景离子水平的研究变得越来越重要。在这里，我们利用市售的活性背景离子还原装置 (ABIRD) 来抑制背景离子，并评估其对液相色谱-电喷雾电离 (LC-ESI)-MS 分析的影响氮‐Q Exactive HF 质谱仪上的聚糖。我们还研究了 ESI 源中不同溶剂蒸气对氮‐MS 进行聚糖分析。当甲醇蒸气充满 ESI 源时，ABIRD 通常对高甘露糖和中性结构没有影响，但会降低某些含有唾液酸、岩藻糖或两者的结构的强度。根据我们对最多已识别数量的调查结果氮‐来自人血清的聚糖，离子源室中的甲醇蒸汽可能会增强氮‐聚糖 LC-ESI-MS 通过改善 ESI 过程中由于其高挥发性而形成的液滴的去溶剂化来进行分析。该协议可以进一步验证并扩展到先进的自下而上的蛋白质组学/糖蛋白质组学研究，用于通过 MS 分析肽/糖肽离子。