The ligand density can be calculated using the Berendsen-de Galan equation:

α = 10⁶ %C/(10² MW _carbon nC – %C MW _ligand) SBET

where α is the ligand density (µmol/m²), %C is the percent carbon (%), MW _carbon is the molecular weight of carbon (g/mol), nC is the number of carbon atoms per bonded ligand, MW _ligand is the molecular weight of the organic bonded ligand (g/mol), and SBET is the specific surface area of silica material (m²/g).

For example, the ligand density of the Cogent UDC-Cholesterol™ stationary phase comes out to approximately 1.5 µmol/m² using this equation.