Zodiac HST C achieves baseline resolution of acetylcholine and methylacetylcholine from their chloride counterions through a combination of cation exchange, complexation, and hydrophobic interactions. This LC/MS-compatible method employs a mobile phase consisting of water, acetonitrile (MeCN or ACN), and ammonium acetate, with detection performed using Evaporative Light Scattering Detection (ELSD).