Stable carbon isotope ratios of POPs — A tracer that can lead to the origins of pollution

An elemental analyzer in combination with stable isotope ratio mass spectrometry (EA–IRMS) was used to demonstrate that two samples of the chloropesticide Melipax discovered in two countries varied only by 0.1‰ in their δ13C values. Gas chromatography interfaced to a stable isotope mass spectrometer (GC–IRMS) was used to study the δ13C values of individual congeners in two technical polybrominated diphenyl ether products, i. e. DE-71 and DE-79, at three different concentration levels. Injections of 4 μg and 5.2 μg of DE-71 and DE-79 were most suited for the determinations. In both products, the δ13C values were usually the more negative the higher the degree of bromination was. The δ13C values of three hexabromo isomers BDE 138, BDE 153, and BDE 154 could be determined in both products. In all cases the δ13C values of the three hexaBDEs were more depleted in δ13C in the higher brominated technical octabromo diphenyl ether DE-79.