USP chapter on Mass Spectrometry 关于UPS在质谱的应用
A mass spectrometer produces ions from the substance under investigation, separates them
according to their mass-to-charge ratio (m/z), and records the relative abundance of each ionic
species present. The instrument consist of three major components (see Figure 1); an ion
source for producing gaseous ions from the substance being studied, an analyzer for resolving
the ions into their characteristics mass components according to their mass-to-charge ratio, and
a detector system for detecting the ions and recording the relative abundance of each of the
resolved ionic species. In addition, a sample introduction system is necessary to admit the
samples to be studied to the ion source while maintaining the high vacuum requirements (~10-6
to 10-8 mm of mercury) of the technique; and a computer is required to control the instrument,
acquire and manipulate data, and compare spectra to reference libraries.
This chapter overview of the theory, construction, and use of mass spectrometers. The discussion
is limited to those instruments and measurements with actual or potential application to
compendial and other pharmaceutical requirements; generally, the identification and quantification
of specific compounds.
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