Which of the following was in the 1940s to analyze amino acids that make up proteins?
genetic engineering
chromatography
radioactive tracers
x-ray diffraction

chromatography In the 1940s and 50s, amino acids were analysed by a technique known as column chromatography. The protein sample is taken in a test tube for analysis and the chemical bonds between the amino acids is broken to isolate individual amino acid chain. Since each different type of amino acid is unique, they react differently to the chemical solution added and react at different times. The color of the remaining substance is then examined to determine the make up of the different amino acids.