GLpKa is Sirius' industry leading instrument for pKa, logP/D and solubility measurement using pH-metric technology. GLpKa has five dispenser units that deliver all necessary reagents automatically. It uses a proprietary Ag/AgCI double junction electrode for accurate pH measurement. An overhead stirrer ensures that the correct level of mixing is used for each type of assay. Temperature control is achieved using an external re-circulating water bath whilst assay temperature is monitored by a PT100 probe. Assays are designed, controlled and processed with our RefinementPro2 software.

In pH-metric methods, pKa is measured by titrating a solution of the sample in water or solvent with acid and base, and calculating the pKa from the shape of the titration curve. This method will always find the pKas of a sample, and easily copes with multiple and overlapping pKas.

LogP is also measured by a pH-metric method, based on a two-phase acid-base titration in a mixture of water and octanol. The assay delivers logP results for the neutral and ion-pair species and a pH vs. logD profile. The method works well for poorly water-soluble samples, because they tend to dissolve in the octanol phase.

Please note: We have discontinued production of new GLpKa systems due to the launch of its successor, the new SiriusT3.