1 research outputs found
Determination of free desmosine and isodesmosine as urinary biomarkers of lung disorder by ultra performance liquid chromatography-ion mobility-mass spectrometry
The elastin degradation products, desmosine (DES) and isodesmosine (IDES) are highly
stable, cross-linking amino-acids that are unique to mature elastin. The excretion of
DES/IDES in urine, in the free form and with associated peptide fragments, provides an
indicator of lung damage in chronic obstructive pulmonary disease (COPD). A quantitative
ion mobility-mass spectrometry (IM-MS) method has been developed for the analysis of free
DES/IDES in urine with deuterated IDES as an internal standard.
Resolution of DES/IDES isomers was achieved in less than five minutes using ultra
performance liquid chromatography (UPLC) combined with ion pairing. The optimized
UPLC-IM-MS method provided a linear dynamic range of 10-300 ng/mL and a limit of
quantitation of 0.028 ng/mL for IDES and 0.03 ng/mL for DES (0.55 ng and 0.61 ng on
column respectively). The method reproducibility (%RSD) was < 4% for DES and IDES.
The UPLC-IM-MS method was applied to the analysis of urine samples obtained from
healthy volunteers and COPD patients. The DES/IDES concentrations in healthy and
COPD urine showed an increase in DES (79%) and IDES (74%) in the COPD samples,
relative to healthy controls. The incorporation of an IM separation prior to m/z measurement
by MS was shown to reduce non-target ion responses from the bio-fluid matrix