2.1 Chemicals and Reagents
All aqueous solutions were prepared
using ultrapure water (18.2 MΩ∙cm) obtained from a Milli-Q water
purification system (Millipore Sigma). All chemicals and reagents were
used as received, without further purification. Buffers containing
0.001% (w/v) Pluronic F-68 were prepared from a 10% (w/v) Gibco
Pluronic F-68 (Thermo Fisher Scientific) stock solution.
Sodium chloride (NaCl), ≥99%; and
magnesium chloride (MgCl2) hexahydrate, ≥98%, USP grade
were purchased from J.T. Baker. Tetramethylammonium chloride (TMAC),
≥98%; tetrabutylammonium chloride (TBAC) hydrate, ≥96%;
tetraethylammonium acetate (TEA-Ac), ≥97%; and
tetraethylammonium tetrafluoroborate
(TEA-BF4), ≥99% were purchased from Acros Organics.
Tetraethylammonium chloride (TEAC)
monohydrate, ≥98% and tetraethylammonium bromide (TEAB), ≥98% were
purchased from Alfa Aesar. Tetrapropylammonium chloride (TPAC), ≥97%
was purchased from TCI America. Bis-tris propane (BTP), ≥98% was
purchased from Sigma-Aldrich. Tris(hydroxymethyl) aminomethane (Tris),
Emprove Essential, USP grade was purchased from Millipore Sigma.
Tris(hydroxymethyl)aminomethane hydrochloride), (Tris-HCl), ≥99%, USP
grade; and 6 N hydrochloric acid solution were purchased from J.T.
Baker.