Search results
Results from the WOW.Com Content Network
The Kovats index of n-alkanes is 100 times their carbon number, e.g. the Kovats index of n-butane is 400. The Kovats index is dimensionless, unlike retention time or retention volume. For isothermal gas chromatography, the Kovats index is given by the equation:
While the different mass detector technologies, namely quadrupole, ion trap and time of flight, can be deemed irrelevant, the chromatography settings such as temperature programming, type of capillary column and choice of column manufacturer heavily affect the empirically determined RI properties. Procedures for the transfer of RI properties ...
Retention time – the characteristic time it takes for a particular analyte to pass through the system (from the column inlet to the detector) under set conditions. See also: Kovats' retention index; Sample – the matter analyzed in chromatography. It may consist of a single component or it may be a mixture of components.
The definition of “absolute” in this case is that calibration of retention time on the column with a set of reference standards is not required to obtain molar mass or the hydrodynamic size, often referred to as hydrodynamic diameter (D H in units of nm). Non-ideal column interactions, such as electrostatic or hydrophobic surface ...
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
Example chromatogram showing signal as a function of retention time. In chromatography, resolution is a measure of the separation of two peaks of different retention time t in a chromatogram. [1] [2] [3] [4]
This isn’t the first time that better sleep has been linked with a lower risk of dementia: A study published in October even found that people with sleep apnea are more likely to develop dementia.
The retention time of the probe molecule is then measured by traditional GC detectors (i.e. flame ionization detector or thermal conductivity detector). Measuring how the retention time changes as a function of probe molecule chemistry, probe molecule size, probe molecule concentration, column temperature, or carrier gas flow rate can elucidate ...