拓展基体辅助激光解吸电离飞行时间质谱仪的检测范围

选用多壁碳纳米管(CNT)作为基质辅助激光解吸电离化飞行时间(Matrix-assisted laser desorption ionization/time of flight,MALDI-TOF)质谱仪的基质,对分子量小于0.8 ku的小分子化合物进行检测,克服了MALDI-TOF MS中的基体干扰,适合进行小分子分析.实验先在正离子模式下检测氨基酸及其衍生物,在正电场条件下清晰地观察到样品的碱金属加合峰M K] 和M Na] 分子离子峰,几乎看不到加氢的离子峰M H] .又在负离子模式下以CNT作为基质对氨基酸样品进行质谱分析,得到单一M-H]-负的分子离子峰,所得到的谱图几乎没有背景干扰,信噪比高.结果证实在负离子模式下可以方便快捷地进行氨基酸检测,从而拓宽了MALDI-TOF MS的应用范围.

In Negative Ion Mode MALDI-TOF MS Analysis of Amino Acids Using Carbon Nanotubes as Matrix

Multiwalled carbon nanotubes were used as the matrix for analysis of small molecules by MALDI-TOF MS,and it was observed tube able to eliminate interference of matrix background ions and suitable for analysis of small molecules(<0.8 ku).Here,we demonstrated this method through analyze amino acids and amino acid derivatives in positive reflection mode.Mass spectra showed that the analytes were ionized as sodium adduct and potassium adduct ,metal ions are the main chemical adduct and peaks of the analytes are not observed in the mass spectra.Previously reported method mainly focused on positive reflection mode.In this work we focused on the development of this new matrix for MALDI to analyze amino acids in negative reflection mode.It was observed from the mass spectra that there was only one intense peak,which was corresponding to-,and under optimal conditions,little or no background peaks appeared in the low mass region,and the intensity and S/N of peaks was enhanced.This method can be utilized in the rapid and sensitive analysis of amino acids,and expand the applied fields of MALDI-TOF mass spectrometry.