Measure free fluoride ions in aqueous solutions quickly, simply, accurately and economically with the Thermo Scientific™ Orion™ Fluoride Electrodes. The Thermo Scientific™ Sure-Flow™ junction allows easy cleaning and is easy to use in tough samples.The half cell electrode requires a separate reference electrode. We recommend the reference electrode 900100 to be used with the half cell electrodes 9409BN and 9409SC.