Keywords:

Abstract:

The usefulness of two chemical tests to detect the presence of proteins in paint media has been studied. A positive microchemical test for phosphate is not any indication of the presence of casein. Due to contamination all the samples analyzed–linseed oil paint, casein or egg tempera–gave similar positive results. Chemical tests which detect the amino acid tyrosine and depend on reaction at the phenolic hydroxyl group of this acid showed neither a difference between proteins nor the distinction between proteins and drying oils. The use of a new immunological "gel-diffusion" technique to identify proteins is suggested and discussed. M.H.S.