Table 1. Composition of stock solutions for ion substitution assay in mM.

Solution	98Na	100K	98Na-Cl	98K-CL	ChCl
NaCl	98	0	0	0	1
KCl	2	100	0	0	1
Na Gluconate	0	0	98	2	0
K Gluconate	0	0	2	98	0
Choline Cl	0	0		0	98
MgSO4 7H2O	0	0	0.5	0.5	0
MgCl2 6H2O	0.5	0.5	0	0	0.5
CaCl2 2H2O	0.5	0.5	0	0	0.5
Ca Gluconate	0	0	0.5	0.5	0
Hepes (pH 7.2)	10	10	10	10	10

Bold face indicates primary salt.