Which digestion buffers are compatible with FabRICATOR-HPLC?

We have tested PBS and 150 mM ammonium acetate, pH7 with good results. More buffers were found to be compatible with FabRICATOR digestion in solution (more info) and should be suitable for FabRICATOR-HPLC as well. However, the ionic strength of the buffer influences retention of the antibody fragments on the FabRICATOR-HPLC column and a minimum of 100-150 mM salt is necessary for IgG1 subunits to elute as a single, narrow peak. Other IgG subclasses or fusion proteins might need some optimization of buffer composition.