UHPLC/MS Analysis of Insulin Variants and Analogs on BIOshell A160 Peptide C18 Using Difluoroacetic Acid as a Mobile Phase Modifier
Materials
analytical column
CONDITIONS
column
BIOshell A160 Peptide C18, 15 cm x 2.1 mm I.D., 2.7 μm particles (66905-U)
mobile phase
[A] 75:25 water (0.1% v/v difluoroacetic acid): acetonitrile (0.1% v/v difluoroacetic acid); [B] 50:50 water (0.1% v/v difluoroacetic acid): acetonitrile (0.1% v/v difluoroacetic acid); (77:23, A:B)
flow rate
0.2 mL/min
column temp.
75 °C
injection
MS, ESI(+) TOF, TIC 100-3000 m/z
injection
0.5 μL
sample
Mixture of six insulin variants, 100 μg/mL, water (0.1% v/v difluoroacetic acid)
Description
Analysis Note
BIOshell A160 Peptide C18 is an ideal column for reversed-phase separations of small proteins to large peptide sequences. There is over 75% sequence similarity between all six of the insulin variants in the sample; therefore, separation of these variants is achieved through the subtle differences in the polarities of surface residues on the peptides. The use of difluoroacetic acid (DFA) has less of an effect on ion suppression than trifluoroacetic acid (TFA), thus allowing for mass spectral detection of the insulin variants.
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