Analytical methods travel

Retention factor A measure of the amount of time an analyte spends in the stationary phase relative to the mobile phase Retention time The time taken for an analyte to travel from the point of injection to the point of detection within an HPLC system Reverse phase chromatography Describes the chromatographic separation in which the stationary phase is nonpolar and the mobile phase is composed of an aqueous, moderately polar liquid Robustness A measure of a method s ability to withstand small but deliberate changes in the method parameters it provides an indication of its reliability during normal usage Selectivity factor See separation factor... 

Wiedemeier and coworkers (1996) have suggested two methods to approximate biodegradation rates in groundwater field studies (a) use a biologically recalcitrant tracer (e.g., three isomers of trimethylbenzene) in the groundwater to correct for dilution, sorption, and/or volatilization and calculate the rate constant by using the downgradient travel time or (b) assume that the plume has evolved to a dynamic steady-state equilibrium and develop a one-dimensional analytical solution to the advection-dispersion equation. 

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