Table 1.

Salt-surface interaction potentials from ASA-based analysis of solubility/distribution studies with model compounds

	μ23/(RTASA) × 103, (m-1 Å-2)*
Salt	Aliphatic C	Aromatic C	Amide (O,N)
Na2SO4	6.0 ± 0.1	5.9 ± 0.2	−6.8 ± 0.5
(NH4)2SO4	3.8 ± 0.1		−3.3 ± 0.3
KF	3.4 ± 0.1	2.4 ± 0.1	−4.6 ± 0.3
GuH2SO4†	2.2 ± 0.3	0.3 ± 0.5	−5.8 ± 1.0
NaCl	2.2 ± 0.1	2.0 ± 0.1	−4.2 ± 0.2
KCl	2.0 ± 0.1	1.7 ± 0.1	−4.2 ± 0.2
KBr	1.7 ± 0.1	1.2 ± 0.2	−4.1 ± 0.4
NaClO4	0.9 ± 0.1	1.1 ± 0.1	−7.0 ± 0.3
NH4Cl	0.8 ± 0.3		−1.2 ± 0.8
GuHCl	0.3 ± 0.1	−0.8 ± 0.2	−3.7 ± 0.4

^*Model compound dataset is identical to that in ref. 17. Ammonium salts were not included in ref. 17 due to scarcity of data; values here are estimates obtained from analysis of two [(NH₄)₂SO₄] or three (NH₄Cl) solubility μ₂₃/RT values and one vapor pressure osmometry μ₂₃/RT value (see Fig.  S1). Salts are assumed to be neither accumulated at, nor excluded from, small amounts of ester oxygen surface (6–13% of total ASA) on model peptides.

^†Obtained from Na₂SO₄, NaCl, and GuHCl values assuming ion additivity.