Electrodes Oxygen sensor

a dissolved oxygen meter laboratory use

the clark-type electrode used oxygen sensor measuring oxygen dissolved in liquid. basic principle there cathode , anode submersed in electrolyte. oxygen enters sensor through permeable membrane diffusion, , reduced @ cathode, creating measurable electric current.

there linear relationship between oxygen concentration , electric current. two-point calibration (0% , 100% air saturation), possible measure oxygen in sample.

one drawback approach oxygen consumed during measurement rate equal diffusion in sensor. means sensor must stirred in order correct measurement , avoid stagnant water. increasing sensor size, oxygen consumption increases , stirring sensitivity. in large sensors there tend drift in signal on time due consumption of electrolyte. however, clark-type sensors can made small tip size of 10 µm. oxygen consumption of such microsensor small practically insensitive stirring , can used in stagnant media such sediments or inside plant tissue.