Experimental exposure to toluene: further consideration of cresol formation in man.

In two separate experiments 10 healthy men each were exposed at rest in an exposure chamber to about 200 ppm toluene in the air. Hippuric acid, o-, m-, p-cresol, and phenol in urine were detected by capillary gas chromatography at the beginning and at the end of exposure, and at variable times after the cessation of exposure. In addition toluene in blood was determined at the same intervals. The results indicate that in addition to hippuric acid, o-, m-, p-cresol are metabolites of toluene; the detoxication lasting 24 hours at least.

Metabolism of toluene in man: gas-chromatographic determination of o-, m- and p-cresol in urine.

Complete separation of phenol, o-, m- and p-cresol was achieved by capillary gas-chromatography. Urinary concentrations of cresols were determined quantitatively in samples from 10 male workers exposed to toluene. Besides p-cresol, o- and m-cresol were found to be urinary compounds in the case of the exposed group in contrast to normal persons. This finding was proved by gas-chromatography/mass spectrometry. The difference between both groups is significant. It is concluded that beside hippuric acid o-, m- and p-cresol are metabolites of toluene.

Synthesis of the C-terminal decapeptide of bovine insulin B-chain.

The liquid-phase synthesis of a decapeptide corresponding to the last 10 amino acid residues of bovine insulin B-chain is described. Modified monofunctional polyethylene glycol containing benzyl bromide functional group was used as the soluble polymeric support. Cleavage of the fully-protected peptide from the polymer was achieved with 1N NaOH in dioxane. The protected peptide was purified by chromatography on Sephadex LH-20. The protecting groups of a sample were removed with anhydrous HF, and the unprotected crude decapeptide was purified by ion-exchange chromatography on carboxymethyl-cellulose. Both peptides were tested for the racemization of individual amino acids by the gas chromatographic method. The results showed that no residue had been significantly racemized.

[Quantitative analysis of L-hydroxyproline in human biological material by gas-chromatography (author's transl)]. / Gaschromatographische Bestimmung von Hydroxyprolin in biologischem Material des Menschen.

Quantitative amino acid analysis by gas chromatography was applied to the determination of 4-hydroxy-L-proline in biological material. After addition of a known amount of allo-4-hydroxy-D-proline, quantitative analysis of 4-hydroxy-L-proline can be performed by gas chromatographic separation of the amino acid enantiomers; since the standard and sample have identical chemical behaviour, they respond identically during derivatization. The accuracy, reproducibility, and sample requirement of this procedure are more advantageous than those of hitherto existing methods. This study is also an example of the application of chiral stationary phases, which permit the simultaneous separation of amino acids and amino acid enantiomers.