In Situ Stabilization of Persistent Organic Contaminants in Marine Sediments

Microprobe two-step laser desorption/laser ionization mass spectrometry (μLMS) is used as a new analytical technique for the detection of polychlorinated biphenyls (PCBs). Three standard Aroclor solutions (Aroclor 1232, 1242, and 1262) and three samples of activated carbon spiked with Aroclor 1242 are examined. All the PCBs present in the Aroclor solutions are clearly identified using μLMS. The distribution of the peaks follows the relative natural abundances of the carbon and chlorine isotopes. μLMS analyses of the spiked particles of activated carbon reveal the presence of PCBs and an abundance of polycyclic aromatic hydrocarbons. The detection limit for PCBs on solid surfaces is determined to be between 1 and 10 ppm. Because the spatial resolution of the μLMS instrument varies between 10 and 40 microns, PCB information at the subparticle scale can be obtained.