Carboxylic acids are usually separated by ion interaction chromatography using a reversed-phase column with quaternary ammonium salts as the IIR and water-methanol or water-acetonitrile as the mobile phase. The more lipophilic the quaternary ammonium ion, the more the acid is retained on nonpolar stationary phases. Such separation systems have been used for the determination of ascorbic acid in fruits and vegetables, as well as carboxylic acids in beverages such as wine, beer and fruit juices.

Gradient elution ion interaction chromatography is also possible. The concentration of the organic modifier or the pH of the mobile phase may be varied to optimize the separation. Figure 4 shows an example of the separation of carboxylic acids on a reversed-phase column by gradient elution using tetrabutylammonium hydroxide as the ion interaction reagent.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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