New Polychlorinated Naphthalene Standards

Polychlorinated naphthalenes (also known as PCNs or simply CNs) comprise a class of compounds of up to 75 congeners containing from one to eight chlorine atoms per naphthalene molecule. PCNs are structurally similar to PCBs, sharing chemical and physical properties. PCNs are hydrophobic, have high thermal and chemical stability, resist weathering in the environment, and have low flammability risks, as well as low to medium volatility.

Chloronaphthalenes are widespread global environmental pollutants that accumulate in biota. They are planar compounds and can have toxicity with a combination of various 2,3,7,8-tetrachlorodibenzo-p-dioxin-like toxic responses. There are three known main sources of environmental pollution with PCNs: 

• Technical PCN formulations
• Technical polychlorinated biphenyl formulations, and
• Thermal and other processes in the presence of chlorine.

Until the 1970s, PCNs were high-volume chemicals commercially produced as mixtures of several congeners, distributed under trade names such as Halowax. Industrial uses of PCNs included cable insulation, capacitors, gauge and heat exchange fluids, instrument seals, and solvents – uses similar to those for polychlorinated biphenyls. Owing to the harmful POP properties and risks related to continuing production, use and releases of PCNs to the environment, the committee members of the Stockholm Convention have listed PCNs as chemicals they are considering for inclusion in a future revision of the treaty.

In a move to help researchers develop methods to clearly identify these compounds in a variety of sample matrices, CIL has developed new calibration and spiking standards for analysis of many of the most important PCN congeners.

Polychlorinated Naphthalenes (PCNs)