Page 115 - Pharmaceutical Organic Chemmistry-3 (Theoritical book) 24-25

Clinical Pharmacy PharmD - 2024/2025 Level 2 Pharmaceutical Organic Chemistry-3 (PC 305)

❖ Mass (MS) spectrometry is an analytical tool useful for measuring

the mass-to-charge ratio (m/z) of one or more molecules present in

a sample.

❖ These measurements can often be used to identify unknown

compounds in sample via exact molecular weight determination.

❖ MS instrument is composed of the following parts:
1. Sample injection port: It is used to introduce a volatile sample into a gaseous ion source at
low pressure. For less volatile samples heating or vaporization is necessary. Non-volatile

and thermally unstable compounds could be detected via another inlet system.

2. Sample vaporizer: It is used to vaporize the sample into gaseous state to be detected.
3. Ion source (electron beam): It converts sample molecules into ions by bombarding the

sample with a beam of electrons from an ion gun & this beam causes fragmentation of the
molecules to form a large number of positively charged ions with various masses.

4. Magnetic deflector: It deflects ions based on its charge (no. of +ve charges) and mass
(heavy or light).

5. Detector: The mass to charge (m/z) ratio is analyzed through the ions that hit the detector.

6. Recorder: A computer that records the MS spectrum.