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研究了聚乙二醇(PEG)为内标物的电喷雾(ESI)/飞行时间质谱(TOF-MS)准确质量测定方法,并应用于5个红霉素类抗生素质子化分子离子(MH~+)的质量测定.与理论值相比,相对误差均在5×10~(-6)以内.PEG可与K~+,Na~+,H~+等形成三种加合离子形式,通过选择适当的实验条件,控制PEG仅以其中的一种加合离子形式出现,这一特点扩大了其应用范围,使之可作为一种普适性的内标物.另外讨论了扫描质量范围、扫描速度等因素对测定结果的影响,并且比较了采用多峰校正法和两峰校正法的结果.结果表明,以PEG为内标的ESI/TOF质谱法可对不稳定碱性化合物的质子化分子离子(MH~+)进行准确质量测定,而且简便、快速.
The method of electrospray ionization (ESI) / time of flight mass spectrometry (TOF-MS) with polyethylene glycol (PEG) as an internal standard was studied and applied to the determination of 5 erythromycin antibiotic protonated molecular ions +), The relative errors are less than 5 × 10 ~ (-6) compared with the theoretical value.PEG can form three kinds of adduct ion forms with K ~ +, Na ~ +, H ~ +, etc. Select the appropriate experimental conditions, the control of PEG only one of the adduct ion form, this feature expanded its scope of application, making it a universal internal standard substance.In addition to discuss the scan quality range, Scanning speed and other factors on the determination results, and compared the results of using the multi-peak calibration method and the two-peak calibration method.The results show that the ESI / TOF mass spectrometry with PEG as an internal standard can stabilize the protonated molecules of unstable basic compounds Ion (MH ~ +) for accurate mass determination, but also simple and fast.