Ion Pair Reagents
Ultra pure Ion pair reagents and buffers
Ion Pair Chromatography is a method for im proving the separation of charged analytes. In the resolution of organic ions with conventional HPLC methods, use of ion pair reagents can enhance peak shape and retention time when comm on remedies such as modifying eluent ratios or changing stationary phase fail.
In the past, chromatographic separation of charged analytes has been achieved by ion suppression (the careful adjustment of the mobile phase PH to result in a nonionized analyte). Determining the optimum mobile phase PH in ion suppression, however, often requires extensive method development. Samples containing more than one ionizable component were often unusable. The imitations of ion suppression Ied to the development of a new, more generally applicable approach to separation of ionized components: ion pair chromatography.
Developed by Dr. Gordon Schill in 1973, ion pair chromatography relies upon the addition of ionic compounds to the mobile phase to promote the formation of ion pairs with charged analytes. These reagents are comprised of an alkyl chain with an ionizable terminus (Figure 1). W hen used with common hydrophobic HPLC phases in the reversed-phase mode, ion pair reagents can be used to selectively increase the retention of charged analytes (Figure 2). For in-depth information, see Ion Pair Details and Ion Pair Method Development
Regis manufactures both ultrapure anionic Sulfonate (S-series) and cationic Quaternary Amine (QSeries) ion pair concentrates in the following alkyl chain Iengths: pentyl, hexyl, heptyl, octyl, and dodecyl. Alkyl chains are represented by cardinal numbers in the naming of our products, i.e., 5, 6, 7, 8, and 12.
Although ion exchange chromatography has become a popular mode of separation, it is not useful in aIl situations. The advantages of ion pair chromatography over ion exchange chromatography are
- Simple preparation of buffers
- Wide choice of carbon chain Iengths for improved retention and separation
- Signiscantly reduced separation time
- Simultaneous separation of both ionized and nonionized solutes
- Highly reproducible results
- Improved peak shape