Measurement of precipitin reactions in the millimicrogram protein-nitrogen range

Exploitation of newer instrumentation and a dye-binding method for protein measurement made possible reduction in volume down to 1/1000 that commonly used, with no greater error. The procedure was tested at two levels, 1- and 10-microl volumes, with human gamma globulin and rabbit antiserum. Of the dyes tested, bromsulfalein proved best for the protein estimation.