The cylic undecapeptides cyclosporin (Csp) A, CspD and dihydro CspC (HCspC) were analyzed by high‐performance liquid chromatography/thermospray‐mass spectrometry (HPLC/TSP‐MS) on line with 1–2 pmol injected on column. Mass spectra were characterized by signals corresponding to the [M + H]+ ion as well as fragment ions derived from he loss of 112 (CspA and CspD) or 44, 114 and 114+44 (HCspC) mass units from the parent ion. The same qualitative profile was observed for negative‐ion acquisition where the ions were formed by proton abstraction. The application of the technique to the characterization of CspA and its major hydroxylated and dealkylated metabolites in human blood samples is presented.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Organic Chemistry