Preparation of radioactive-labeled polystyrene latex monodispersed submicron aerosols

Submicron monodispersed polystyrene latex aerosols have been labeled radio-actively with 131I by emulsion polymerization. By the use of catalytic reagents and heat, the polymerization process is started, and subsequently the contaminants are removed by dialysis. Gamma counting of an aliquot of the labeled suspension indicated that about 40% of the initial activity remained on the particles. No significant removal of the label was found with heat or reduced pressure. During application of the labeled aerosol to filter penetration and collection studies, gamma-counting values were obtained which compared closely with microscopy values. Also, the labeling of the particles did not significantly increase the particle size.