(a)
(b)
(c)
Figure 3: Comparative chromatograms showing isocratic RP-HPLC separation of mixed standard, L-citrulline, and L-arginine in different mobile phases: (a) 0.7% H3P04 : ACN (90 : 10); L-citrulline and L-arginine were unretained and coeluted at value close to zero; (b) 0.7% H3P04; L-citrulline and L-arginine were slightly retained and partially separated; (c) 0.1% H3P04; L-citrulline and L-arginine were efficiently separated with reproducible peaks. The peaks marked represent (1) L-arginine and (2) L-citrulline.