Abstract: A pH gradient mobile phase preparation kit is described. The preparation kit includes a first component and a second component. The first component includes a first reagent separate from a second reagent. The first reagent, the second reagent, and a solvent together provide a volatile buffer solution having a low pH. The second component includes a base. The base mixed in the solvent provide a volatile base solution having a high pH. A method of separating and detecting one or more analytes comprised in a matrix of components in a sample, using the kit is also described.