Page 135 - Tandem Techniques

Page 117

Now, it is clear from the relative values of (rc), (rt), and (dp), that

Thus

Now, again from the Plate Theory [3], the peak variance in volume units of a connecting tube of
length (lt) is given by

where (nt) is the number of theoretical plates in the connecting tube.

Now, by definition, Thus, replacing by (Ht) from equation (3.18),

Employing equation (3.19), the standard deviation of the dispersion from connecting tubes, 0.005 in.
I.D., can be calculated when used with columns operating at their optimum linear mobile phase
velocity. Results for tubes of different length, connected to the small standard LC column 3 cm long,
packed with particles 3 gm in diameter, are shown in Figure 3.3. The curves relate the standard
deviation of the dispersion contributed by the tube to the tube length. The horizontal lines represent the
maximum dispersion that can be tolerated by the column and is equivalent to one third of the column
dispersion given in Table 3.2.