Each eluted sample was dried down into a round-bottom flask using a rotary evaporator, and the dried material transferred into an 8 mL amber glass vial using small volumes of acetonitrile (ACN) and ultrapure water (MilliQ). A residue which could not be dissolved in ACN or ultrapure water was removed using 50 % MeOH, which was then removed using a rotary evaporator. We suspected that this residue was leached column material, and so each daily fraction was redissolved in 50 % MeOH and centrifuged for 15 mins at 6500 rpm. A white precipitate was pelleted out allowing the supernatant sample to be pipetted from the top. These samples were then freeze-dried and weighed. The total mass of these freezedried fractions was 1.8 g. Each fraction was redissolved in 50 % MeOH and combined to produce a single 115 mL sample.