Electrochemical (EC) detectors detect chemicals by measuring changes in current across an electrode pair. Many common EC detectors are used for detection of gas phase analytes.  In these instruments, a target gas contacts the electrode and causes an electrochemical reaction takes place, this produces a change in current which is the basis for analyte detection. A variety of EC sensors and detectors are available for identifying gases such as H₂S, CO₂, TIC/TIMs, explosives, and dozens of other chemicals. Most EC-based units are configured with sensors for specific gases. Many units incorporate multiple sensors into a single instrument.  Instruments with this configuration can detect multiple gases simultaneously. Most EC sensors are portable or handheld instruments.  The technology is mature with many manufacturers offering commercial instrumentation across a very broad price range of $1,000 to $20,000+.