Unsaturated HC's on HP-Pona

The light hydrocarbons up to C3/C4 range are difficult to separate with a HP-PONA or similar column unless you have a thick film.  You may be able to get it by starting at sub-ambient temperature.  Here are a couple of references from similar columns:

https://www.agilent.com/cs/library/chromatograms/456C.jpg

https://www.agilent.com/cs/library/applications/A00678.pdf

An alumina column would be better for the light hydrocarbons, but those columns have difficulty for compounds heavier than C6-C7, so usually a backflush is employed when using that column.  Here is a representative chromatogram on a GS-Alumina column:

https://www.agilent.com/cs/library/chromatograms/C802.pdf

The light hydrocarbons up to C3/C4 range are difficult to separate with a HP-PONA or similar column unless you have a thick film.  You may be able to get it by starting at sub-ambient temperature.  Here are a couple of references from similar columns:

https://www.agilent.com/cs/library/chromatograms/456C.jpg

https://www.agilent.com/cs/library/applications/A00678.pdf

An alumina column would be better for the light hydrocarbons, but those columns have difficulty for compounds heavier than C6-C7, so usually a backflush is employed when using that column.  Here is a representative chromatogram on a GS-Alumina column:

https://www.agilent.com/cs/library/chromatograms/C802.pdf