Table 4.

Retention times (t_Ri), unadjusted relative retention (r_G) and separation factors of amino acids derivatized with OPA-IBLC. As internal standard, an OPA-IBLC-derivative with an m/z = 481 was chosen, which was eluting around 48 min. Chromatographic conditions are described under Table 1.

Amino acid	[M+H]+	Elution order	tRi(L)in min	tRi(D)in min	rG(L)1	rG(D)1	rG(L)/rG(D)
Thr	409	L < D	32.23	32.82	0.679	0.692	0.981
allo-Thr	409	L < D	33.92	34.93	0.715	0.736	0.971
Leu	421	L < D	48.83	50.07	1.029	1.051	0.979
Ile	421	L < D	47.95	49.55	1.013	1.047	0.968
allo-Ile	421	L < D	48.20	49.55	1.019	1.047	0.973
NorLeu	421	L < D	48.14	49.43	1.024	1.051	0.974
t.but.-Leu	421	L < D	48.80	49.08	1.038	1.045	0.993
erythro-β-MeOTyr	501	D < L	39.64	38.30	0.822	0.782	1.051
threo-β-MeOTyr	501	L < D	37.30	41.06	0.773	0.828	0.934

¹The Unadjusted Relative Retention r_G was calculated as t_Ri/t_R(St).