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The specificity of multi-column liquid chromatography of neutral urinary steroids as evaluated by comparison with parallel gas chromatography and mass spectrometry.

The use of gas chromatography/mass spectrometry is advocated as the best currently available methodology for the validation of a routine assay for steroid analysis. This is documented by comparative studies by gas chromatography/mass spectrometry and spectrophotometry of peak material obtained in routine assays by multi-column liquid chromatographic techniques.

Chromatography, Gas↗

[Identification of Legionella by gas phase chromatography of fatty acids and high performance liquid chromatography of ubiquinones].

The fatty acids and ubiquinones of 44 reference strains corresponding to species of Legionella and 3 strains of Legionella isolated in the environment have been evaluated. The analysis of fatty acids profiles allows a classification of 22 species into 4 groups depending on the predominance of some branched-chain fatty acids of linear fatty acids. As for ubiquinones our results for the 22 species corroborate the classification in 5 groups established by Moss in 1983 based on the study of 10 species of Legionella. The analysis of fatty acids composition combined with ubiquinones content has allowed us to identify the antigenically similar strains which cannot be differentiated by direct immunofluorescence on one hand (strain 1) and on the other a more precise approach to the identification, before DNA-ADN hybridization of strains of new species (strains 2).

Chromatography, Gas↗

Oxybuprocaine and five metabolites simultaneously determined in urine by gas chromatography and gas chromatography-mass spectrometry after extraction with Extrelut.

We describe a gas-liquid chromatographic (GC) method for determination of oxybuprocaine, and a gas chromatographic-mass spectrometric (GC-MS) method for simultaneous determination of four of its nine metabolites in urine. We used an Extrelut column to simply and rapidly extract oxybuprocaine and its metabolites from urine. For the GC-MS analyses, we monitored the characteristic fragment ions at m/z 353, 395, 369, 411, and 235 for 3-butoxy-4-aminobenzoic acid (metabolite 2, M-2), 3-butoxy-4-acetylaminobenzoic acid (M-3), 3-hydroxy-4-aminobenzoic acid (M-4), 3-hydroxy-4-acetylaminobenzoic acid (M-5), and methaqualone (internal standard), respectively. We quantified the glucuronide of M-2 after enzymic treatment. The assay's selectivity and reproducibility (within-day and between-day CVs less than 8% for all metabolites) make it applicable to determine oxybuprocaine and its metabolites in human urine. Mean 9-h urinary excretion of oxybuprocaine and its five metabolites from four healthy volunteers was 89.2% after a 100-mg oral dose.

Chromatography, Gas↗