Analysis of biological substances and geochemical samples, of both terrestrial and extraterrestrial origin, for amino acids at the 1–10 nanogram per gram level has been achieved by gas-liquid and ion-exchange chromatographic methods in the past two years. With increasing sensitivity, contamination becomes a most important problem. This paper reports the amino acid distribution and interfering peaks normally observed from several sources of contamination by the GLC method of Gehrke et al. Reagents and laboratory supplies such as water, butanol, methylene chloride, hydrochloric acid, latex gloves, and masslin fibers were investigated as well as skin, dandruff, saliva, hair, and fingerprints from the human body. It was found that significant contamination appeared in nanogram to microgram amounts from several of these sources. However, with the application of the rigorous analytical techniques suggested contamination can be successfully eliminated and analysis of samples containing 1–10 ng per gram is readily achieved. The analysis of Onverwacht chert is presented to demonstrate the application of the GLC nanogram method to a geochemically important sample. The GLC method has been used for the analysis of amino acids in biomedical samples and the Apollo 11, 12, and 14 returned Lunar samples.