“…Polyunsaturated hydrocarbons with non-conjugated double bonds (e.g. squalene) form stable charge transfer complexes with Ag + Si-gel (Guha and Janak, 1972;Cagniant, 1991;Nocun and Andersson, 2012), which can severely decrease recovery, even though such strong retention can aid in the separation of aromatic from saturated compounds (Cagniant, 1991;Hollender et al, 2003;Aponte et al, 2013;Dillon et al, 2012;Nocun and Anderson, 2012). To minimize π electron complexation with Ag + (Cagniant, 1991), this ASE method incorporated four precautionary measures: (i) inserting the filter above the Ag + Si-gel to prevent intermixing with activated Si-gel during cell construction or handling, (ii) adjusting the amount of activated Si-gel to prevent PAHs from reaching the Ag + Si-gel during the initial hexane elution, (iii) loading the TLE between layers of activated Si-gel and (iv) inverting the columns to reverse flow direction after the initial hexane elution.…”