Comparison of methods for measurement of organic compounds at ultra-trace level: analytical criteria and application to analysis of amino acids in extraterrestrial samples.

The need for criteria to compare different analytical methods for measuring extraterrestrial organic matter at ultra-trace levels in relatively small and unique samples (e.g., fragments of meteorites, micrometeorites, planetary samples) is discussed.

Chromatographic method for diaminopimelic acid detection in calcareous rocks. Presence of a bacterial biomarker in stromatolites.

The presence in the environment of diaminopimelic acid (DAP), a specific eubacterial marker, can be attributed to that of bacteria. We report a reliable and highly sensitive method for the quantification of DAP in calcareous rocks. It consists of acid hydrolysis of rock powder, purification of DAP by chromatography on Dowex 50W and Spherogel AA-NA+ columns, and quantitative analysis by high-performance liquid chromatography.

A high-performance liquid chromatography method for the detection of diaminopimelic acid in urine.

We describe a quantitative assay for diaminopimelic acid (DAP) in urine. It involves (i) hydrolysis of urine samples, (ii) purification by several different liquid chromatography steps, and (iii) analysis by high-performance liquid chromatography on a reversed-phase C18 column. Tritiated-DAP, the internal standard, allows one to precisely follow the DAP-containing fractions and to determine the yield during purification.