How Chromatographic Ions Are Used in Laboratories

Ion chromatography (or ion exchange chromatography) is a process that allows the separation of ions and polar molecules based on the nature of the molecular charge.

This can be used for many types of charged molecules including large proteins, small nucleotides and amino acids. Solutions to be injected are usually called separate samples and individual components are identified as analytes. This is often used in protein purification, water analysis and for quality control purposes.

Ion exchange chromatography maintains analyte molecules using coulomb (ionic) interactions. The surface of the stationary phase displays an ionic functional group that interacts with the analyte ion with the opposite charge. This chromatography category can be further divided into cation exchange chromatography and anion exchange chromatography. Ionic compounds consisting of cationic species and anionic species can be maintained by the stationary phase.

Cation exchange ion chromatography maintains a positively charged cation because the stationary phase shows a negatively charged functional category. Anion exchange chromatography maintains anions that display a positively charged functional category. Note that the strength of cation ions or anions in the mobile phase can be adjusted to shift the equilibrium position and, therefore, the retention time. Ion calorimeter indonesia chromatograms can be used to show chromatograms obtained with ion exchange columns.

A typical ion chromatography technique involves manually entering a sample or using an autosampler, into a known sample volume loop. A buffered aqueous solution known as the mobile phase carries a sample from the loop into a column containing several types of stationary phase material. This is usually a resin or gel matrix consisting of agarose or cellulose beads with functional groups that are covalently bound. The target analyte (anion or cation) is maintained in a stationary phase but can be eluted by increasing the concentration of similarly charged species. This will shift the analyte ion from the stationary phase.

For example, in cation exchange chromatography, positively charged analytes can be removed by entering positively charged sodium ions. An interesting analyzer must then be detected by several methods, usually with conductivity or UV / Visible light absorbance.

To control an ion chromatography system, a chromatographic data system is usually needed. Some of these chromatographic data systems can also be used to control gas chromatography and HPLC systems.

Proteins have many functional groups that can have positive and negative charges.

Ion chromatography separates proteins according to their net charge. This depends on the composition of the mobile phase. By adjusting the pH or ionic concentration of the mobile phase, various protein molecules can be separated. For example, if the protein has a net positive charge at pH 7, it will tie the column of negatively charged beads, but the negatively charged protein will not. Change pH so that the net load on negative proteins will cause it to elute.

Reaching elution by changing the ion power of the mobile phase is a more subtle effect. This works because the ions from the mobile phase will interact with the immobilized ions more preferably than the ions in the stationary phase. This protects the stationary phase of the protein and vice versa. This allows the protein to be eluted. Ion exchange column preparation scale is used for protein purification.

Ion chromatography is a powerful technique for ensuring low ion concentration and is very useful in studies of environmental and water quality.