Based on the most recent recommendations of the International Union of Pure and Applied Chemistry (IUPAC), which appeared in Pure and Applied Chemistry 65: 819-872 (1993). A Eddy diffusion, or packing factor term of the van

Deemter (packed column) equation. « Separation factor; the adjusted retention time of the more retained solute relative to that of the less retained solute.

B Longitudinal diffusion term of the van Deemter and Golay equations.

P Column phase ratio. The column volume occupied by mobile (gas) phase relative to the volume occupied by stationary phase. In open-tubular columns:

cM, cS Solute concentrations in mobile and stationary phases, respectively.

C Resistance to mass transfer (or mass transfer) in the van Deemter (or Golay) equations; Cm and CS denote mass transfer from mobile to stationary and from stationary to mobile phases, respectively.

dc Inner diameter of the column. Both mm and |im are commonly used. The latter, while consistent with the units used for df, implies three significant figures, which is rarely true.

df Thickness of the stationary phase film, usually in | m.

D Diffusivity; DM and DS denote solute diffusivities in the mobile and stationary phases, respectively; usually given in cm2 s_1.

F Volumetric flow of the mobile phase, usually in cm3 min-1. Many practical chromatographers assume equivalency with (and hence employ) mL min-1.

FID Flame ionization detector.

GC-MS The combination of gas chromatography and mass spectrometry, usually a single integrated unit in which fractions separated by GC are sequentially introduced to the MS.

H Length equivalent to one theoretical plate (height equivalent to a theoretical plate): H = L/N. When measured at uopt, the result is termed Hmin.

k Solute retention factor (formerly partition ratio). Ratio of the amounts of a solute (or time spent) in stationary and mobile phases, respectively. Because all solutes spend tM time in the mobile phase, k = [tR- tM]/tM, and k = tR/tM.

Kc Distribution constant. Formerly KD. Ratio of solute concentrations in stationary and mobile phases, respectively: Kc = cS/cM.

P. Husek, Institute of Endocrinology, Prague, Czech Republic

Copyright © 2000 Academic Press

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook

Post a comment