Initial analysis of asparagine
and citrulline mixture
HPLC analysis, using the above described Platinum
EPS C18 column and elute conditions, of a mixture
of asparagine and citrulline yields a single peak
refl ecting co-elution of asparagine and citrulline
(5.85 min) (Figure 1). The ZORBAX Rx-SIL
column enabled slight separation of these two
ureides, giving only slight differences in retention
times (5.41 min for asparagine and 5.44 min for
citrulline). Also, one other ureide, allantoic acid,
elutes at essentially the same time (5.40 min) as
asparagine and citrulline. Thus, asparagine and
citrulline analysis using the ZORBAX Rx-SIL
column is problematic, especially in the presence
of allantoic acid. Thus, the ZORBAX column is
unsuitable for quantitative analysis using the above
described conditions.