Em. Fujinari et Jd. Manes, NITROGEN-SPECIFIC DETECTION OF PEPTIDES IN LIQUID-CHROMATOGRAPHY WITHA CHEMILUMINESCENT NITROGEN DETECTOR, Journal of chromatography, 676(1), 1994, pp. 113-120
High-performance liquid chromatography with chemiluminescent nitrogen
detection (HPLC-CLND) in the reversed-phase mode was used to quantitat
e peptides that were isolated from casein hydrolysate. When CLND is us
ed simultaneously with a UV detector in peptide mapping, unique quanti
tative information about the nitrogen distribution of the sample is ob
tained. Nitrogenous compounds without UV chromophores are easily detec
ted by CLND without pre- or post-column derivatization. Of further sig
nificance, the non-nitrogenous compounds in the sample matrix are tran
sparent to the detector. This paper will focus primarily on the analys
is of two peptides, identified as 1 and 2. The UV peptide map showed p
eptide 2 as the largest component. On the other hand, the CLND results
indicated that peptide 1 was the major peak. RP-HPLC amino acid analy
sis of the peptides 1 and 2 confirmed the CLND results. This analysis
shows that peptide 1 was the major component and did not contain aroma
tic amino acid residues. Peptide 2 however, contained aromatic groups
with strong chromophores, thereby explaining the UV response.