Evaluation of ring-opening metathesis polymerization (ROMP)-derived monolithic capillary high performance liquid chromatography columns

Novel monolithic capillary HPLC columns were prepared via ring opening metathesis polymerization (ROMP) within the confines of fused silica columns with 200 μm i.d. using norborn-2-ene (NBE), 1,4,4a,5,8,8a-hexahydro-1,4,5,8, exo, endo-dimethanonaphthalene (DMN-H6) as monomers, 2-propanol and toluene as porogens and RuCl2(PCy3)2(CHPh) as initiator. Using the monolithic capillary HPLC columns, different sets of analytes (i.e. standard systems) were used for the evaluation of the monolithic columns: (i) a protein standard consisting of six proteins in the range of 5000-66 000 g/mol, (ii) an insulin-albumin standard, and (iii) a peptide standard obtained from a tryptic digest of cytochrome C. With these three different standard systems the reproducibility of synthesis in terms of separation performance proved to be 1-2% relative standard deviation in tR. Variation of polymerization parameters had a significant influence on the monolithic morphology and therefore separation efficiency and back pressure. The maximum analytical loading capacity of ROMP-derived monolithic capillary columns for albumin was found to be 30-125 ng, depending on the monomer content. Long-term stability studies showed no alteration in separation performance.