What is ion pair extraction?

What is ion pair extraction?

Ion pair extraction, i.e. extraction of ionized solutes into organic phases by adding an oppositely charged ion to the system, has been used for many decades. In this technique, the distribution of an ion into the organic phase is enhanced by the formation of an ion pair between the two oppositely charged ions.

How does ion pair chromatography 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.

How do ion pairing reagents work?

The ionic samples form an ion-pair with ion-pair reagents in the mobile phase to become electrically neutral. The increase in hydrophobic character of the ion-pair results in a greater affinity for the reverse stationary phase and leads to sample resolution.

What is ion pair complexes?

Known also as ionic associations or ionic association complexes , ion pairs are pairs of oppositely charged ions held together by Coulomb attraction without formation of a covalent bond [1].

What is the difference between ion pair and ion exchange chromatography?

The key difference between ion pair and ion exchange chromatography is that, in ion pair chromatography, ions in the sample can be “paired” and separated as the ion pair whereas, in ion exchange chromatography, ions in the sample can be separated as cations and anions separately.

What is ion pair transport?

Ion pairing is shown to effectively increase the lipophilicity and transport rate of polar drugs across lipid membranes. The proposed mechanisms of IPT are discussed in detail. A marked change in drug properties upon ion pair formation is necessary to improve the bioavailability of hydrophilic ionizable drugs.

In which mechanism intimate ion pair is formed?

In chemistry the intimate ion pair concept introduced by Saul Winstein describes the interactions between a cation, anion and surrounding solvent molecules. In ordinary aqueous solutions of inorganic salts an ion is completely solvated and shielded from the counterion.

Why do we use TFA?

TFA is widely used as a mobile phase additive in the HPLC separation of biological molecules, such as proteins and peptides, because it acts as an ion-pairing reagent and equilibrates quickly so that it can be used with gradient elution.

What is the basic principle of ion exchange chromatography?

Principle of Ion Exchange Chromatography The molecules separated on the basis of their charge are eluted using a solution of varying ionic strength. By passing such a solution through the column, highly selective separation of molecules according to their different charges takes place.

Which type of drug gets absorbed by ion pair transport?

Which types of drugs get absorbed by ion-pair transport? Explanation: Ion-Pair Transport is the mechanism where absorption of drugs like quaternary ammonium compounds, sulphonic acids get absorbed. These drugs can get ionize at all pH conditions.

What is the function of the ion pump?

Ion pumps are channels that use the ATP hydrolysis energy to transfer ions from one side of a membrane to the other against their electrochemical gradient (Harold, 1986; Laüger, 1991). Similar to passive channels, they are selective, i.e. a pump structure is only adapted to the passage of a particular ion.

What is contact ion pairs?

When there is about one solvent molecule between cation and anion, the ion pair may be termed solvent-shared. Lastly, when the ions are in contact with each other, the ion pair is termed a contact ion pair. Even in a contact ion pair, however, the ions retain most of their solvation shell.

How does ion exchange process take place?

Ion exchange process As water passes through this resin bed, ions attach to the resin beads releasing the loosely held solution into the water. After a time, the beds become saturated and the exchange resin must be regenerated or recharged. To regenerate, the ion exchange resin is flushed with a salt brine solution.