With the addition of MgCl_2,NPEO form the adduct of [M+MgCl]~+. Through comparison of spectra,addtion of various amount of K~+ into NPEO samples could display the change of peak intensity between ~+ and ~+.

• 样品中的钠、钾离子的浓度影响对应加合离子的谱峰强度。 样品中加入M gC l2,可在谱图上观察到[M+M gC l]+离子的谱峰。