Qualitative analysis of trimethylsilylated daunosamine and N-alkylated analogs by gas chromatography-mass spectrometry

✍ Scribed by Paul A. Andrews; Patrick S. Callery; Feng-te Edward Chou; Matthew E. May; Nicholas R. Bachur

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 725 KB
• Volume: 126
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(82)90513-9

✦ Synopsis

A gas chromatography-mass spectrometric method is described for the precise chemical identification of the sugar residues of daunorubicin and the N-alkylated anthracycline analogs. Parent drug or purified bihary metabolites from rabbits were hydrolyzed with 0.2 N HCI for 15 to 30 min at 100°C. The generated aglycones were removed by chloroform extraction, and the remaining aqueous extract was evaporated under nitrogen. The residue was dissolved in trimethylsilylimidazole/pyridine.

The resulting silylated daunosamine moiety was chromatographed on a 3% OV-17 column coupled via a jet separator to the source of a mass spectrometer. The natural cY-anomer, which was assigned to the major peak, eluted first. Electron ionization analysis of the silylated sugars displayed extensive fragmentation. lsobutane chemical ionization provided spectra with intense protonated molecular ions [MH]+ and limited fragmentation. In all cases the later eluting @anomer gave identical although more intense fragments than the cY-anomer. Common fragment ions Seen were [MH]+, [MH-90]+, [MH-116]+, and [MH-130]+. Daunosamine has been detected from as little as 5.7 nmol daunorubicin. N-Renzyldaunorubicinol was identified as the major biliary metabolite in rabbits following dosing with 3.0 mg/kg N,N-dibenzyldaunorubicin.

This method has been applied to the analysis of glucosamine and may find utility in the analysis of many other amino sugars.