What is selectivity coefficients?
A selectivity coefficient is the equilibrium constant for the reaction of displacement by one ligand of another ligand in a complex with the substrate. Binding selectivity is of major importance in biochemistry and in chemical separation processes.
What is ion selectivity coefficient?
The selectivity coefficient is a numerical measure of how well the membrane can discriminate against the interfering ion. To put this in perspective, if an electrode has equivalent responses to the two ions, then kij = 1.0.
What are ion selective electrodes give examples?
Glass membranes are made from an ion-exchange type of glass (silicate or chalcogenide). This type of ISE has good selectivity, but only for several single-charged cations; mainly H+, Na+, and Ag+. A very common example of this type of electrode is the pH glass electrode.
What is a potentiometric selectivity coefficient?
In this method, the potentio- metric selectivity coefficient is defined as the activity ratio of primary and interfering ions that give the same potential change under identical conditions.
What is selectivity of a drug?
Selectivity will be used to describe the ability of a drug to affect a particular population, i.e., gene, protein, signaling pathway, or cell, in preference to others. For example a selective drug would have the ability to discriminate between, and so affect only one cell population, and thereby produce an event.
What is the most common ion selective electrode?
Ion-selective electrodes (ISEs) are potentiometric sensors that include a selective membrane to minimize matrix interferences. The most common ISE is the pH electrode, which contains a thin glass membrane that responds to the H+ concentration in a solution.
What does the selectivity coefficient tell us is it better to have a large or a small selectivity coefficient?
For reference: Definition of selectivity coefficient where ai represents the activity of an ion other than the target ion denoted by i, and is a value indicating the impact that ion B has on the sensor used to measure ion A. The smaller this value, the better the selectivity with respect to the target ion.
What is ISE principle?
Principle of ion-selective electrode (I.S.E.) consists of a thin membrane across which only the intended ion can be transported. The transport of ions from a high conc. to a low one through a selective binding with some sites within the membrane creates a potential difference.
What does the selectivity coefficient mean in a circuit?
The selectivity coefficients is the approximate apparent increase caused by the interfering ion. A selectivity coefficient of 0.1, for example, implies that the electrode is ten times more responsive to the primary ion than to the interfering ion.
How is the selection coefficient used in genetics?
Selection coefficient, in genetics, a measure of the relative reduction in the contribution that a particular genotype (genetic composition) makes to the gametes (sex cells) as compared with another genotype in the population. It expresses the relative advantage or disadvantage of specific traits with respect to survival and reproductive success.
Which is an example of a selectivity method?
Selectivities in methods. Current analytical methods are based on multistage separation and detection principles. Metals are often determined with methods based on detection selectivity, e.g, atomic emission spectrometry. Separation techniques for all types of species rely on selectivity in the separation process, separation selectivity.
What is the difference between selectivity and specificity?
Selectivity or specificity The terms selectivity or specificity are in many cases used interchangeably. As specificity is considered as an absolute term, it cannot be graded. IUPAC has earlier stated that “specificity is the ultimate of selectivity”.