Abstract: A stationary phase for a liquid chromatograph and process for making is provided. The stationary phase material may have a modified base substrate and a fluorinated carboxylic acid covalently bonded thereto through an amide or ester bond. The stationary phase may have a substantially consistent shape selectivity characteristic with an ?TBN/BaP of less than 1 within a temperature range of at least 10-70° C. Advantageously, a fluorinated stationary phase has a shape selectivity characteristic exhibited with an ?TBN/BaP of less than 1 with a mobile phase having up to at least 30% water. A process for making the stationary involves mixing a substrate material or fluorinated carboxylic acid with a reactive alkylsilane linker and at least one organic solvent to form a first solution. The other of the substrate material or fluorinated carboxylic acid is then added to the first solution, or to a product separated from the first solution, to form a second solution.