Mass Spectrometryによる製剤分析 (第4報)

Abstract

In the mass spectra of opium alkaloids, parent peak (M+ ion peak) often becomes a base peak. Quantitative determination of opium alkaloids by mass spectrograph can be made by comparison of the parent peak of individual alkaloids with that of the reference standard of definite quantity added, and by calculation of the amount from preliminarily prepared calibration curve. The parent peak varies with ionization voltage. At a low ionization voltage, other fragment peaks do not appear and M+ ion peak can be detected clearly but this M+ ion peak itself is small. When the ionization voltage is elevated, M+ ion peak becomes higher but many other fragment peaks appear at the same time and overlapping of the peaks occur.In the present series of works, examinations were made on the relationship between the intensity of M+ ion peak and ionization voltage. It was concluded that ionization voltage of 10-80eV is appropriate when comparing the height of M+ ion peak but for calculation of overlapping of fragment peaks from reference standard, ionization voltage of 70eV, usually used for measurement of mass spectrum, seems to be the most appropriate.