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Ion chromatography (or ion-exchange chromatography) is a form of chromatography that separates ions and ionizable polar molecules based on their affinity to the ion exchanger. [1] It works on almost any kind of charged molecule —including small inorganic anions, [ 2 ] large proteins , [ 3 ] small nucleotides , [ 4 ] and amino acids .
Diagram of ion concentrations and charge across a semi-permeable cellular membrane. An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts: The chemical gradient, or difference in solute concentration across a membrane.
An example total ion current chromatogram from an LC-MS analysis. The total ion current chromatogram (TICC) represents the summed intensity across the entire range of masses being detected at every point in the analysis. [2] [3] The range is typically several hundred mass-to-charge units or more. In complex samples, the TICC often provides ...
Ion mobility spectrometry-mass spectrometry (IMS/MS or IMMS) is a technique where ions are first separated by drift time through some neutral gas under an applied electrical potential gradient before being introduced into a mass spectrometer. [43] Drift time is a measure of the collisional cross section relative to the charge of the ion.
Ionic bonds generally occur when the difference in electronegativity between the two atoms is greater than 2.0; Pauling based this classification scheme on the partial ionic character of a bond, which is an approximate function of the difference in electronegativity between the two bonded atoms. He estimated that a difference of 1.7 corresponds ...
where t D is the ion drift time, Δt D is the Full width at half maximum, L is the tube length, E is the electric field strength, Q is the ion charge, k is the Boltzmann constant, and T is the drift gas temperature. Ambient pressure methods allow for higher resolving power and greater separation selectivity due to a higher rate of ion-molecule ...
Earl W. McDaniel has been called the father of ion mobility mass spectrometry. [1] In the early 1960s, he coupled a low-field ion mobility drift cell to a sector mass spectrometer. [2] The combination of time-of-flight mass spectrometry and ion mobility spectrometry was pioneered in 1963 at Bell Labs. In 1963 McAfee and Edelson published an IMS ...
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. [1] [2] Ion associates are classified, according to the number of ions that associate with each other, as ion pairs, ion triplets, etc. Ion pairs are also classified according to the nature of the interaction as contact, solvent-shared or ...