High sensitivity analysis of neutral underivatized oligosaccharides by nanoelectrospray mass spectrometry
High sensitivity analysis of neutral underivatized oligosaccharides by nanoelectrospray mass spectrometry
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DOI：
10.1021/ac970624w
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发表时间：
1997-11-15
影响因子：
7.4
通讯作者：
Stahl, B
中科院分区：
文献类型：
--
作者：
Bahr, U;Pfenninger, A;Stahl, B
纳米电喷雾电离克服了传统微尺度强制流动电喷雾电离中发现和报道的中性寡糖的敏感性问题。对于从三糖到分子质量达6 kDa的较大聚合物的一系列化合物，10(-5)M的样品浓度，即总样品负荷为10pmoL，在离子陷阱质谱仪中产生非常强烈的单阳离子或多阳离子分子离子。在稀释系列中，举例说明，在10(-8)M的水平上，分子离子信号可以清楚地记录下来，S/N比约为7，在本实验中只消耗了100amol的样品。对低聚糖-多肽混合物的研究表明，在传统的ESI中，寡糖被抑制，而在纳米ESI中，两种分析物都以类似的高强度被检测到。目前纳米ESI固有的非常低的速率约为30nL/min，再加上高信号强度，使得充分利用离子陷阱质谱仪的MSN能力进行结构分析成为可能。从不到1亩的L样品溶液中，可以连续进行直到MS7的碎裂实验，以获得关于复杂低聚糖结构的有价值的信息。
Nanoscale electrospray ionization (nano-ESI) overcomes the sensitivity problems found and reported for neutral oligosaccharides in conventional microscale forced-flow ESI. For a series of compounds ranging from trisaccharides to larger polymers with molecular masses up to 6 kDa, sample concentrations of 10(-5) M, i.e., 10 pmol total sample load, yielded very intense singly or multiply cationized molecule ions in an ion-trap mass spectrometer. In a dilution series, it is exemplified that, at the 10(-8) M level, molecule ion signals can be clearly registered with a S/N ratio of about 7, Only 100 amol of sample has been consumed in this experiment, Investigation of an oligosaccharide-peptide mixture revealed that the oligosaccharide is suppressed in conventional ESI, whereas in nano-ESI both analytes are detected at comparable and high intensities, Mechanistic implications are discussed, emphasizing the influence of surface activity for the two ESI techniques. The very low now rates inherent to nano-ESI of about 30 nL/min, together with the high signal intensity, make it possible to fully employ the MSn capabilities of an ion-trap mass spectrometer for structural analysis. From less than 1 mu L of sample solution, it is possible to make consecutive fragmentation experiments up to MS7 to obtain valuable information about the structure of complex oligosaccharides.