Polystyrene microbeads functionalized with surface carboxyl groups (diameter = 0.99 μm (μP1), 1.04 μm (μP2), and 0.20 μm (μP3)) were obtained from Bangs Laboratories, Inc. (Fishers, IN); FC04N,
PC04N, and
PC02N, respectively. BODIPY disulfonate fluorophore (BODIPY
2–) was obtained from Molecular Probes (Eugene, OR).
Pluronic F108 was purchased from BASF (Florham Park, NJ). Tris–HCl buffer solution was prepared by dissolving reagent grade
Trizma base (Sigma-Aldrich, St. Louis, MO) in deionized water (18.0 MΩ cm,
Milli-Q Gradient System, MilliporeSigma, Burlington, MA) and then adjusting the solution pH to 8.1 using
1.0 M HCl (Fisher Scientific, Hampton, NH). Microfluidic channels were fabricated using poly(dimethylsiloxane) (PDMS) prepared from a silicone elastomer kit (
Sylgard 184, Dow, Midland, MI).
Davies C.D, & Crooks R.M. (2020). Focusing, sorting, and separating microplastics by serial faradaic ion concentration polarization †Electronic supplementary information (ESI) available: Solution conductivity calibration curve; electrophoretic mobility measurements; numerical simulations; normalized conductivity with BPE1 “on”; Tris concentration with BPE1 and BPE2 “on”; simulated rate of convection; movies showing sorting by fICP; focusing and sorting by serial fICP; focusing, sorting, and separating by serial fICP. See DOI: 10.1039/d0sc01931c. Chemical Science, 11(21), 5547-5558.