Polarographic measurements of oxygen concentration with Clark-type electrode (Hansatech Instruments Ltd.; https://www.hansatech-instruments.com) have been widely used in photosynthesis and respiration research. The Clark-type electrode provides a fast, effective and accurate method to measure the oxygen concentration in either liquid- or gas-phase. It was used for instance in following publications Müller-Moulé P. et al, Plant Physiol (2004) 134(3): 1163–1172,  Takagi D.et al, Plant Physiol (2016) 171(3): 1626–1634

The Clark-type electrode is covered by an oxygen-permeable Teflon membrane that enables the equilibrium of dissolved oxygen between the sample compartment and the electrode surface. The reduction of dissolved oxygen on the platinum cathode (Pt) results in the current flow that is proportional to the oxygen concentration in the measuring cell. The concentrated electrolyte solution (0.5 M KCl) ensures electrical contact between the platinum cathode and the silver anode (Ag) in the polarographic electrode unit. The polarization voltage is necessary for a stable and linear relationship between the oxygen partial pressure and the resulting current. The Clark-type electrode requires regular calibration.

The Oxylab+ system consists of a highly sensitive Clark-type polarographic oxygen electrode, mounted within an electrode chamber and connected to the control unit. It provides a highly versatile solution to oxygen measurements in liquid samples between 0.2 – 2.5 ml with uniform illumination.

• PC operated oxygen electrode control unit Oxylab+
• Oxygen electrode chamber with 4 optical ports and integral Clark-type polarographic oxygen electrode.
• LED1/W white light source
• OxyTrace+ Windows® software for data acquisition, hardware control & data analysis

Location: room B3-38-51

Left: Clark-type electrode; middle: Oxylab+ measuring system; right: older model of a Clark-type electrode