CRS_Guide

MCI GEL CRS series for optical resolution

MCI GEL CRS series are HPLC packed columns suitable for optical resolution of amino acids and hydroxycarboxylic acids.

Separation mechanism

Stationary phase for MCIGEL CRS10W / CRS15W is based on a reversed-phase silica gel that is modified with a newly developed optical active ligand. Optical resolution on this phase is dominated by the interaction between the solute molecules and optical active ligand on the stationary phase. Copper(II) in the eluent is essential for this interaction, which functions as mediator between sample molecule and active ligand. Simultaneously, hydrophobic interaction contributes to enhance the resolution.

CRS10W is used genrally. CRS15W is the optical isomer of CRS10W and elution order are reversed.

MCI^(R) GEL CRS series columns are only for analytical uses. Preparative or larger scale use is not available.

Applications of MCI GEL CRS series

Example of retention time on MCI GEL CRS10W column

	Amino Acid	eluent CuSO₄ mM	flow rate mL/min	retention time (L-isomer) min	separation factor a	resolution Rs
1	Orn·HCl	0.1	0.2	6.8	1.26	<1
2	Lys·HCl	0.1	0.2	7.7	1.45	<1
3	Ala	0.1	0.5	11.0	1.39	1.4
4	His·HCl	0.1	0.5	10.5	1.63	1.7
5	Ser	0.1	0.5	10.1	1.25	1.0
6	Thr	0.1	0.5	11.3	1.29	1.3
7	Cit	0.5	0.5	10.4	1.75	2.3
8	Hyp	1.0	0.2	23.8	1.23	1.1
9	Pro	1.0	1.0	7.3	2.13	4.5
10	Val	1.0	1.0	8.9	2.04	5.0
11	Nval	1.0	1.0	11.5	2.07	4.7
12	Asp	2.0	0.5	13.2	1.18	0.8
13	Glu	2.0	1.0	16.2	1.54	2.3
14	Ileu (DL)	2.0	0.5	30.4	2.14	6.5
15	Ileu (allo)	2.0	0.5	21.9	1.97	6.0
16	Leu	2.0	1.0	14.6	1.97	4.6
17	Nleu	2.0	1.0	24.1	2.16	6.5
18	Met	2.0	1.0	10.3	1.64	2.6
19	Tyr	2.0	1.0	22.5	1.85	5.3
20	Eth	2.0	1.0	26.4	1.69	5.0
21	Phe	2.0	1.0	37.8	1.84	6.3

Operating instructions

For equilibration between copper(II) and stationary phase ligand, it is advised to condition the column for 2 - 3 hours before analysis and after changing eluent.
For hydrophilic amino acids, a low flow rate (0.2-0.3 mL/min) yields better resolution.
For hydrophobic amino acids, addition of methanol or acetonitrile in the eluent (maximum 15 %) enables faster elution and better resolution.
Do not flow an organic solvent or high concentration of hydroorganic solvent into the column. The stationary phase will be fatally damaged and will lose resolution capability in consequence. Please be particulary careful when one HPLC equipment is shared with reversed-phase mode or normal-phase mode uses.
Do not use acid or alkali for adjusting pH of the eluent. Also do not use buffer solutions. Column performance will be damaged because of a blockage of the column with precipitation of copper salt.
It is impossible to regenerate a deteriorated column.