Coupling liquid chromatography with redox chemiluminescence detection

✍ Scribed by J.J. DeAngelis; R.M. Barkley; R.E. Sievers

• Book ID: 104145813
• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 851 KB
• Volume: 441
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(01)84660-4

✦ Synopsis

The post-column oxidation of many chemical species with dilute nitric acid, nitrous acid, or nitrite ion produces nitric oxide, which is subsequently detected by its chemiluminescence reaction with ozone. Organic compounds, such as sugars, react with dilute nitric acid at elevated temperature and pressure to produce a surrogate nitric oxide pulse for measurement on a chromatographically useful time scale. In addition, certain inorganic reducing agents, e.g., iron( react under similar conditions and are sensitively detected. Ultraviolet irradiation can initiate the redox reactions of easily oxidized inorganic species with aq. nitric acid at 25°C and it also enhances the reactivity of analytes at elevated temperatures.

Aqueous nitrate ion is not effective as a redox reagent, while nitrous acid and nitrite ion are less potent oxidizing agents than nitric acid. A post-column reaction system is described and the characteristics of redox reactions of potential analytes with aq. nitric acid and other reagents are discussed. Illustrative chromatograms which show the high-performance liquid chromatographic separation and chemiluminescence measurement of sugars at ppm levels are presented.