Table 2.

MS identified products of CYS, MET, and HIS with PAA oxidation.^a

	m/z	Molecular weight	Retention time (min)	Peak Areab ($\times$105)
CYS	120	121(M)	1.60	–
	152	M+32	1.69	0.06
	168	M+48	1.56	0.56
	239	2M −1	1.58	0.15
MET	148	149 (M)	2.31	1.66
	164	M+16	1.69	0.71
HIS	154	155 (M)	2.20	4.00
	186	M+32	2.12	4.76

^aInitial concentration of amino acids and PAA were 10 and 131 μM, respectively.

^bPeak area values for amino acids and corresponding products at 1 min for CYS, 30 min for MET and HIS.