How do ion pairing reagents work?
In ion pair chromatography, the solute ion is distributed between the mobile and the stationary phase together with an ion of opposite charge (a so-called counterion). The technique is often used in reversed-phase chromatography as a convenient method to control the retention of solutes.
What is ion pair mechanism?
The ion-pair mechanism can perhaps best be approached by considering the process of ionization and dissociation of a substrate RX. This can be considered a stepwise process of ionization to a contact or intimate ion pair within a solvation sheath or cage followed by separation of the two ions, R+ and X-.
What is the use of ion pair reagent?
Ion Pairing Reagents are use as mobile phase additives, which allow the separation of ionic and highly polar substances on reversed phase HPLC columns.
What detectors are used in ion pair chromatography?
UV detectors are widely used. Therefore ion-pair reagents must lack UV absorption themselves to obtain highly sensitive detection of samples. The UV absorption of sodium alkanesulfonates and quaternary ammonium salts is minimal so that these reagents can be used for reliable HPLC analysis.
What is ion pairing agents?
Ion-pairing agents are compounds that contain both an ionic functional group and a hydrophobic portion, such as a hydrocarbon chain.
What is the principle of ion chromatography?
Ion-exchange chromatography retains analyte molecules on the column based on coulombic (ionic) interactions. The ion exchange chromatography matrix consists of positively and negatively charged ions. Essentially, molecules undergo electrostatic interactions with opposite charges on the stationary phase matrix.
How do you combine ion pairs?
An ion pair, in the context of chemistry, consists of a positive ion and a negative ion temporarily bonded together by the electrostatic force of attraction between them. Ion pairs occur in concentrated solutions of electrolytes (substances that conduct electricity when dissolved or molten).
Is ammonium acetate an ion pair reagent?
Ammonium acetate (10 mM) was used as ion pairing reagent without however achieving the chromatographic separation of the isomeric oligonucleotide adducts [29].
What is true for ion pair?
An ion pair, for the physicist, is the positively charged particle (positive ion) and the negatively charged particle (negative ion) simultaneously produced by the addition of sufficient energy to a neutral atom or molecule to cause it to dissociate into oppositely charged fragments.
What is meant by ion pair reagent?
Ion-pairing reagents consist of large ionic molecules having a charge opposite to the analyte of interest as well as a substantial hydrophobic region that allows interacting with the stationary phase, plus associated counter-ions. In total, IPC results in different retention of analytes, thus facilitating separation.
What is an ion pairing agent?
Ion-pairing agents are compounds that contain both an ionic functional group and a hydrophobic portion, such as a hydrocarbon chain.
What is ion pair chromatography?
Ion Pair Chromatography is a method for improving 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 common remedies such as modifying eluent ratios or changing stationary phase fail.