The fiber was collected with stainless-steel tweezers, wiped with Kim-wipe, transferred to a glass vial, and extracted with acetonitrile. For C12 and C14-BACs and both DADMACs, the sedimented kaolinite was extracted with acetonitrile containing 1% formic acid for 1 h, followed by centrifugation for 15 min. For shorter chain BACs (C6, C8, C10), kaolinite was not analyzed and the concentration sorbed to kaolinite was estimated from the mass balance calculation. The loss to the tube wall was assumed to be log-linearly related to Cw, estimated from the results of the no-kaolinite vials, and included in the mass balance calculation. The loss estimated this way was 1-13% of the C6, C8, and C10-BACs added to kaolinite suspensions and had only a small contribution to the mass balance.