Page 107 - Pharmaceutical Organic Chemmistry-3 (Theoritical book) 24-25

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

❖ Infrared (IR) spectroscopy is the measurement of the interaction of infrared

radiation with chemical compounds.

❖ Infrared radiation (IR): “Infra” means “below,” so infrared is the form of non-visible

light radiation just “below” (or beside) the red end of the visible light spectrum.

❖ It is used to identify chemical functional groups in solid, liquid, or gaseous forms.

IR Instrumentation

❖ IR instrument is composed of the following parts:
1. IR source: Emits infrared radiation over a wide range of wavelengths using Nernst or

Glower’s lamp.
2. Sample Cell: Holds the sample being analyzed, either solids, liquids, or gases.

3. Reference cell: Holds the used reference (simplest reference is air or water).
4. Monochromators: Selects specific wavelengths of infrared light for analysis. It disperses

radiation using a prism.
5. Detector: Captures the intensity of infrared radiation transmitted through the sample &

converts infrared into an electrical signal for analysis.

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