Total Organic Carbon (TOC) analyzers perform two functions: they oxidize the organic carbon in a sample to CO2 and measure the CO2 produced. What makes TOC analyzers different is the method they use to oxidize the organics and the methods used to detect the resulting CO2.
The three main methods of CO2 detection used commercially are:
Non-dispersive infrared (NDIR)
Direct Conductometric (Non-selective Conductometric)
Membrane Conductometric Detection (Selective Conductometric)
NDIR TOC detectors measure CO2 in the gaseous phase, while conductometric TOC detectors measure CO2 in the liquid phase.