Warfarin (acid analyte, pKa 5) and codeine (basic analyte, pKa 8) are analyzed on a reverse-phase HPLC column. The mobile phase composition is 50:50 water:methanol, its pH is about 7 but it is not buffered. The results show low retention times, poor peak shape, and co-elution of both analytes. At the current pH, please show the proportion of both analytes found in both the mobile phase (MP) and stationary phase (SP). (Hint: Using a logarithmic rule of thumb)
10 : 90 Warfarin distribution in MP : SP ; 10 : 90 Codeine distribution in MP : SP
90 : 10 Warfarin distribution in MP : SP ; 90 : 10 Codeine distribution in MP : SP
99 : 01 Warfarin distribution in MP : SP ; 90 : 10 Codeine distribution in MP : SP
01 : 99 Warfarin distribution in MP : SP ; 10 : 90 Codeine distribution in MP : SP