IMPROVEMENT OF ANALYTICAL SENSITIVITIES FOR THE DETERMINATION OF ANTIMONY, ARSENIC, CADMIUM, INDIUM, IODINE, MOLYBDENUM, SILICON AND URANIUM IN AIRBORNE PARTICULATE MATTER BY EPITHERMAL NEUTRON-ACTIVATION ANALYSIS

As part of an ongoing Great Lakes deposition study, we have determined a series of heavy metals in air filter samples collected near Lake Ontario. To decrease our detection limits for key elements used in our receptor modeling, we have employed instrumental epithermal neutron activation analysis (NAA) and Compton suppression techniques. Our detection limits were much better than those with thermal NAA, typically 0.3 ng for Sb, 0.7 ng for As, 8 ng for Cd, 0.2 ng for In, 14 mug for I, 5 ng for Mo and 2 ng for U. Silicon, which is usually not reported in conventional NAA results for air filters, was routinely determined at the 60 mug level. Accuracy was corroborated by analyzing the certified reference material concurrently.