Retention of small molecules on polymethacrylate monolithic capillary columns

Improved Sensitivity of Ultralow Flow LC–MS-Based Proteomic Profiling of Limited Samples Using Monolithic Capillary Columns and FAIMS Technology

“…Currently, conventional nanoLC separations are carried out in packed fused-silica capillary columns with internal diameters (IDs) between 50 and 100 μm, typically operated at a flow rate between 100 and 400 nL/min, as the process of high quality packing in nanoLC columns with IDs below 50 μm is reportedly challenging. ,, Monolithic stationary phases have been an attractive alternative for high complexity samples in proteomics applications as a result of their high permeability, low backpressure, ease of preparation, diverse surface chemistries, significant control on the porosity and structure of the stationary phase, high separation efficiency, and broad selectivity. ,,,,− While in the past, monolithic columns posed issues with inconsistent reproducibility, more recent reports show reasonable reproducibility of column preparation and performance; moreover, there are examples of monolithic columns that were commercialized. ,, Rapid and highly efficient separation of complex peptide, protein, metabolite, oligonucleotide, and other small or large molecule mixtures can be routinely achieved using monolithic columns. ,, When connected to MS, high-efficiency ultranarrow bore monolithic LC columns (≤20 μm ID) operated at ultralow flow (ULF) rates (≤20 nL/min) significantly increase the sensitivity of nanoESI-MS, resulting in an improved depth of qualitative and quantitative molecular profiling of limited clinical and biological samples. , Smaller eluent droplets generated by the nanoESI emitter with ULF LC–MS result in higher ionization efficiency of analyte species, lower ion suppression, and a miniaturized nanoESI plume, leading to higher ion transfer efficiency and improved MS sensitivity. The performance of ULF columns has been effectively demonstrated in high sensitivity LC–MS-based bottom-up and top-down proteomics applications and has also established the potential of ULF LC–MS for reaching the sensitivity levels required for proteomic profiling of individual cells. ,,, Despite the reported attractive advantages, the current implementations of the ULF LC–MS technology still lack the sufficient robustness and reproducibility required to become commercialized and widespread.…”

“…11,29,35 Rapid and highly efficient separation of complex peptide, protein, metabolite, oligonucleotide, and other small or large molecule mixtures can be routinely achieved using monolithic columns. 28,32,36 When connected to MS, highefficiency ultranarrow bore monolithic LC columns (≤20 μm ID) operated at ultralow flow (ULF) rates (≤20 nL/min) significantly increase the sensitivity of nanoESI-MS, resulting in an improved depth of qualitative and quantitative molecular profiling of limited clinical and biological samples. 11,18 Smaller eluent droplets generated by the nanoESI emitter with ULF LC−MS result in higher ionization efficiency of analyte species, lower ion suppression, and a miniaturized nanoESI plume, leading to higher ion transfer efficiency and improved MS sensitivity.…”

Advances and Innovations in Liquid Chromatography Stationary Phase Supports

“…(96) The Urban group investigated the retention of small molecules in polymethacrylate monolithic capillary columns and very recently used a post-polymerization UV-initiated grafting reaction with bifunctional poly(ethylene glycol)dimethacrylate monomers to optimize the hydrodynamic and kinetic properties of these columns. (97) (98) They found that the use of shorter crosslinking monomer increased the formation of small pores and minimized mass transfer resistance. Both column efficiency and mass transfer resistance also improved when the amount of crosslinking monomer was reduced.…”