What are the methodologies for each?

1. Electrolytes (Na, Cl, K)

2. Sweat Chloride

3. Bicarb

I think one of the tests for #1 is ISE or iron selective electrodes.

For #2 I know the sweat chloride test is used to determine if a patient has cystic fibrosis and uses something called pilocarpine iontophoresis.

Are there any I missed and what testing methodologies are there for Bicarb or HCO3?

Thank you for all your help!