Amino-phase packing surface structure

In a similar fashion, the retention behavior of 23 tripeptide epimers (with the basic structure Z-Ala-X-Val-OMe, where X is either the d or l form of the inserted amino acid) was studied on a C g column (A = 220 nm) using a series of isocratic methanol/water mobile phases [471]. The k values for all the lll and ldl forms and the resulting a values are tabulated for each epimer. Reasonable elution times were achieved, with mobile phases ranging fixim 60% to 80% methanol. The LDL-epimers were consistently more retained than the LLL-epimers. The authors attribute this to a larger surface area presented to the packing material in the ldl conformation. 

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