PubMed · 4626220
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G Schomburg, F Weeke, B Weimann, E Ziegler. 1972. Data processing in gas chromatography.. https://doi.org/10.1002/anie.197203661
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The insolubility of calcium phosphate in water is a significant stumbling block in the chemistry required for the origin of life. The discovery of alkyl phosphonic acids in the Murchison meteorite suggests the possibility of delivery of these water-soluble, phosphorus-containing molecules by meteorites or comets to the early Earth. This could have provided a supply of organic phosphorus for the earliest stages of chemical evolution; although probably not components of early genetic systems, phosphonic acids may have been precursors to the first nucleic acids. Here we report the synthesis of several phosphonic acids, including the most abundant found in the Murchison meteorite, by ultraviolet irradiation of orthophosphorous acid in the presence of formaldehyde, primary alcohols, or acetone. We argue that similar reactions might explain the presence of phosphonic acids in Murchison, and could also have occurred on the prebiotic Earth.
Measurements of polyamines, polyamine conjugates and their metabolites in tissues, cells and extracellular fluids are used in biochemistry, (micro)biology, oncology and parasitology. Decarboxylation of ornithine yields putrescine. Aminopropylation of putrescine yields spermidine, and aminopropylation of spermidine yields spermine. Spermidine and spermine are retroconverted to putrescine and spermidine, respectively, by initial N-acetylation and subsequent polyamine oxidation. The intermediate N-acetylputrescine, N1-acetylspermidine and N8-acetylspermidine are the major urinary N-acetylpolyamines. Polyamines and N-acetylpolyamines are terminally degraded to non-alpha-amino acid metabolites by oxidative deamination and aldehyde dehydrogenation. Chromatography with on-line detection is the most commonly applied profiling method for polyamines, N-acetylpolyamines and their non-alpha-amino acid metabolites. Cation-exchange and reversed-phase high-performance liquid chromatography require pre- or post-column derivatisation, followed by UV-Vis spectrophotometric or fluorimetric detection. Isolation and derivatisation precedes gas chromatography with flame-ionisation, nitrogen-phosphorus, electron-capture or mass spectrometric detection. High-performance liquid chromatography and gas chromatography of polyamines are not competitive techniques, but rather supplementary.
Three methods for the determination of 2,5-hexanedione (2,5-HD) in urine were compared in order to assess their applicability for toxicokinetic studies and biological monitoring of occupational exposure to n-hexane. Two of them were based on derivatization, followed by gas chromatography and electron-capture detection. Of these two, one is a modification of the other, already published, method. The third one involves direct extraction of 2,5-HD followed by gas chromatography and flame-ionization detection. To determine 2,5-HD in urine of workers occupationally exposed to n-hexane, the most straightforward method, direct extraction of 2,5-HD from urine, has been proven to be the most suitable. However, in case of very low concentrations of 2,5-HD in urine, or analysis of small samples of blood, e.g. in kinetic studies, it is necessary to use a more sensitive procedure. The sensitivity of the methods based on the derivatization of 2,5-HD followed by electron-capture detection, was, as expected, much higher in terms of analytical reliability. By using these methods, however, precautions are necessary to avoid a matrix effect.