Page 87 - Multidimensional Chromatography

Orthogonal GC–GC 79

Figure 4.2 Examples of multidimensional gas chromatography separation arrangements: (a)
small heartcut zones 1–4 are transferred to the second column and run together on this analyt-
ical column, where ideally greater selectivity sees the zones more spread-out on the latter col-
umn; (b) if contiguous zones from 1D are all simply passed to 2D, then we get severely
overlapping zones, and as a result this will be similar to just analysing the sample on the sec-
ond column.(c) the contiguous zones 1–5 are transferred to separate traps, and each can be
independently analysed in the second dimension, thus giving rise to five 2D chromatograms;
(d) if we implement the right modulation process on small contiguous zones from 1D, which
is rapid with respect to the peak width times, between 1D and 2D, preferably with zone com-
pression and fast GC conditions on 2D, then we can obtain the GC GC technique.