The precise molecular weights for common isotopically labelled amino acids are included in this module. Subsequent separation procedures reduced the amount of isotopically pure einsteinium roughly tenfold. He used isotopically labeled oxygen-18 and radioactive chlorine to study these reactions. This is often an isotopically labeled version of the analyte. Such CO can be converted to methane and from there to isotopically pure synthetic diamonds. The necessity to use expensive, highly isotopically enriched N is a significant factor to overcome. The water is not Earthly contamination but isotopically different from terrestrial water. The name "proton" refers to isotopically pure H. Isotopically pure diamond can have a significantly higher thermal conductivity.