Chromatography Forum

My auditor is holding my feet to the fire over section 10.2.4.1. Resolution of 2 pairs of peaks, anthracene and phenanthrene should be separated by baseline, and chrysene and benz[a]anthracene by a valley no more than 25%.
Wants us to develop some calculations to prove we do it as now we only print pictures of the peak pairs.
We have never been able to get baseline resolution for anthracene and phenanthrene using an HP5 column.
Anyone else having these issues?

I do not have the resolution issue at all, I use Restek's Rxi-5sil-MS column (30m x 0.25 mm x 0.25 μm), and the temperature program as follows: initial at 55 °C, hold for 1 min; ramp at 10 °C/min to 200 °C; ramp at 7 °C/min to 320 °C, and hold 0.36 min.
The carrier gas is helium at a constant flow of 1.2 mL/min.

We also use a Restek RXi-5Sil MS column. You will not get the resolution you're looking for with a HP-5; we have tried in the past. The Sil phase makes a really big difference in separating the PAHs. We get baseline resolution of both of the pairs that you're worried about, as well as less than a 25% valley for benzo(b) and benzo(k) fluoranthene.