Medium Throughput p<i>K</i> _a Determinations of Drugs and Chemicals by Reverse Phase HPLC with an Organic Gradient

Abstract

Abstract A semi‐automated method to determine pK a values of drugs and chemicals by reverse phase HPLC is described. The method uses the capabilities of a crosslinked reverse phase HPLC column (Agilent extend C‐18) as a separation device. The pK a value was determined based on the different retention behaviors of the charged, multiply charged, and uncharged species at different pH conditions. The advantages of this method are low sample consumption, suitability for less soluble compounds, high purity samples not necessary, no spectral shift needed, high sample throughput, easy set up, high sensitivity, low cost, good precision, and agreement with literature values.