Splitted peaks are often seen when using on-column injection. The injection error can be fixed by using retention gaps.
Using Splitless and PTV type injection techniques we do not require retention gaps. If splitless methods are implemented where the oven temperature is MUCH lower then solvent boiling point, a retention gap will help. These methods are basically not correct, as the oven temperature must be approx. 20°C below solvent bp., but there will be several labs that have to follow the books. Using a retention gap will help here.
When the PTV is used as an On-Column injector, peak splitting is a risk. Biodiesel methods, using the PTV, can show peak splitting depending on amount injected and starting oven temp. This phenomenon can be prevented using a retention gap. In the figure, an Integrated retention gap was used using 0.32mm fs Rtx-Biodiesel column. The setting of injection parameters will be less critical. The absence of a coupling also simplifies this method.
Further reading: Using Guard Columns and Retention Gaps in GC (Part 1)
