Infrared Spectroscopy in Clinical Chemistry
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Ng, L. M. and Simmons, R. 2006. Infrared Spectroscopy in Clinical Chemistry. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 SEP 2006
Infrared (IR) spectroscopy measures the absorption of IR radiation by chemical bonds in a material. Chemical structural fragments of molecules, known as functional groups, tend to absorb IR radiation in the same frequency range regardless of the structure of the rest of the molecule in which the functional group is located. This correlation between the structure of a molecule and the frequencies at which it absorbs IR radiation allows the structures of unknown molecules to be identified and structural or chemical changes of the molecule to be followed. Traditionally, IR spectroscopy has been one of the most important physical methods in the chemical laboratory as it plays an important role in the elucidation of structures and the identification of organic and inorganic compounds. The quantitative analysis of samples is straightforward and is not affected by the physical state of the sample. Gaseous, liquid, and homogeneous and inhomogeneous solid samples all can be conveniently studied.
Applications of IR spectroscopy in clinical chemistry have progressed rapidly in recent years. IR pathological analysis is becoming increasingly important in the detection of biochemical changes in body fluids and tissues. Information obtained from their IR spectra can be used to identify diseases. Advanced investigations are carried out using different data-analysis techniques such as multivariate analysis. Using a pattern-recognition approach, IR spectroscopic data provide a nonsubjective aid in the diagnosis of the disease state and the staging of the disease. Unlike most colorimetric or electrochemical/enzymatic clinical chemistry assays, IR spectroscopic analysis is applicable to a variety of body fluids and tissues: whole blood, plasma or serum, synovial fluid, saliva, urine, cells, and membranes. The methodology is fast and readily automated. Sample preparation is simple and no special reagents or other consumables such as electrodes are required, making IR spectroscopy a low-cost operation. The most attractive advantage of the method is the potential for a rapid multicomponent analysis to be carried out from a single spectrum.