How do you extract benzalkonium chloride?

You can extract benzalkonium chloride using Strata X-CW.  benzalkonium chloride has a quaternary amine functional group that will interact strongly with the carboxylic acid groups of Strata X-CW sorbent, and the long alkyl chains will interact strongly with the hydrophobic PSDVB base.  An acidic elution will deionize sorbent chemistry, along with a strong reversed phase solvent (organic) to terminate sorbent-analyte interaction and recover the analyte.  A starting method is outlined below:

To a Strata X-CW cartridge,

Condition/Equilibrate with 4 bed vol of methanol, and then deionized water (pH 6-7)

Load pretreated sample slowly

Wash with 4-8 bed vol of deionized water (pH 6-7), followed by 4-8 bed vol of methanol
Dry cartridge on full vacuum for 10 minutes

Elute with 2x 4 bed vol of 5% formic acid in methanol