pH analysis of small biological samples

The Metrohm Biotrode combination glass electrode brings highly accurate and quick measurements of biology/protein pH measurements in very small sample volumes

Designed with a 3mm diameter immersion system, the Biotrode is said to be well suited for pH measurements in volumes down to 60µl. It can be easily used in sample vessels with small diameters, such as microplates, for quick analysis.

The Biotrode uses a spherical glass membrane manufactured from a special low-impedance membrane glass to ensure short response times. The electrode uses the Metrohm 'Long Life' reference system with the Ag/AgCl cartridge; its silver ion barrier ensures an extended life and consistent measurements, the company says.

Typically, biological samplesparticularly proteinscan be a problem with pH measurements. The Biotrode reference system uses a new electrolyte called 'Idrolyte', a specialised viscous electrolyte based on a glycerol and aqueous KCl solution, which helps to reduce the denaturing of the proteins in the sample. Its viscous nature also reduces any streaming potentials, allowing the Biotrode to be used with a sample that is stirring.

Biotrode features a plied platinum diaphragm that acts as a bundle of capillaries and replaces the troublesome fritted glass diaphragm.