Page 197 - Illustrated Pocket Dictionary of Chromatography

200 TOTAL ION CHROMATOGRAM (TIC)

total ion chromatogram (TIC) Collects and displays the inten-
sity of all ions that are detected across the entire defined molecular
weight range. TICs give the greatest amount of total information with
respect to the ions generated by the sample. However, many of these
ions are of no importance and so the data collected are superfluous
to the analysis at hand. See single ion monitoring.

total permeation volume, V i The entire system volume (inter-
stitial and pore) accessible to all molecules that can enter all available
pores. This is usually expressed in terms of a molecular weight such
that for all molecular weights less than this value, the elution volume
is the same and equal to V i. See molecular weight calibration curve.

Total porosity, e T The ratio of the total mobile phase volume, V M,
to that of the total column volume, V C:

e T = V M V C

This value can also be expressed in terms of the intraparticle porosity,
e i, and the interstitial porosity, e e:

e T = e e + e i (1 - e e )

transmittance The ratio of transmitted radiation intensity, I, to
that of the incident radiation intensity, I o, is defined as the transmit-
tance, T:

T = I I o

The attenuation of I o is due to the absorption of the radiation by
one or more components of the sample. It should be noted that the
relationship between transmittance and absorbance is A = log (I o/I)
= log (1/T).

Trennzahl separation number (TZ) Estimates how many
paeks (of similar width) will fit between two other peaks of an homol-
ogous series:
TZ = (t - t ) (w 12 2 , + w 12 1 , ) -1
r 2 r 1
where t r2 and t r1 are the retention time of the latest- and earliest-eluting
series peaks and w 1/2,2 and w 1/2,1 are their peak widths at baseline,
respectively.