Polychlorinated Biphenyls (PCBs) are a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. Their chemical properties and physical stability led to wide spread commercial use as dielectric and coolant fluids in electrical equipment and in heat transfer fluids. Because of their stability, they are considered a persistent organic pollutant.

It is important to test for PCBs in water, soil, and small organisms due to their adverse health effects.

PPB Analytical takes advantage of gas chromatography-electron capture detector (GC-ECD) to test PCB samples. This is because of its high sensitivity which is capable of detecting PCBs at minute concentrations.