Faster elution and smaller 2tR

1
Interpreting GCxGC results (assume linear
temperature programming)
Wrap-around occurrence of retention times on 2D
that exceed the modulation period, causing peaks
to be plotted at 2tR actual 2D retention n
(modulation period)
NO
Y E S
?
Strategies to reduce 2tR
reduce 2L
Faster elution and smaller 2tR
2L 1.6m
2L 0.8m
Increases speed on 2D and gives smaller 2tR, but
gives elution at lower T, increasing 2tR
Sometimes no change
increase u
u 50cm/s
u 90cm/s
Compounds to enter 2D at higher T, which reduces
2tR
increase rT
rT 6C/min
rT 11C/min
Greater time between pulses, and therefore less
wraparound. BUT, make sure there are NM ? 4!!!
increase PM
PM 6 s
PM 5 s