New PCN Standard

Polychlorinated naphthalenes (PCNs) are a group of 75 compounds that are structurally similar to PCBs. Until the 1970s, PCNs were high-volume chemicals commercially produced as mixtures of several congeners marketed as Halowax and other commercial trade names. Total global production of PCNs was estimated at 150,000 metric tonnes until production ceased in Europe and North America in the 1980s.

PCNs were mainly used as wood preservatives, paint and engine oil additives, for cable insulation and in capacitors. Due to the harmful persistent organic pollutant (POP) properties and risks related to the possible continuing production, use and releases of PCNs to the environment, at the Persistent Organic Pollutants Review Committee Ninth Meeting held in Rome, October 14–18, 2013, the committee members of the Stockholm Treaty published an addendum on “Risk management evaluation on chlorinated naphthalenes.” This document can be downloaded from “POPRC.9 Documents” tabulated in the Stockholm Convention website (click here.)

Recently, the International Organization for Standardization (ISO) published a GC-MS method for the analysis of PCNs in water and wastewater: Only the overview is visible on-line (click here); the entire method is available for purchase. CIL has developed standards for all unlabeled congeners cited in the method, including both isomers of pairs that are not resolved using currently available columns.

CIL has recently completed production of 30 of the 75 unlabeled congener standards and is nearing completion of five more. All homologue groups are well represented, and standards are now available for all congeners in the important hexa- and heptaCN homolog groups, as well as both monoCNs and octaCN. Isotope-labeled standards in most homologue groups have also been developed, with at least one 13C10 congener from the Tetra- through OctaCN homologue groups in inventory, and a ¹³C₁₀-monoCN (2-monoCN; PCN-2) and DiCN (1,5-diCN; PCN-6) also nearing completion. PCN mixtures designed for exposure analysis (but applicable to other environmental methodology) are also available, as well as a mono-octaCN mixture.

This is an expanding analytical area, and the list of individual PCN standards and PCN mixtures is likely to grow in the future.