C₁₈‐bound porous silica monolith particles as a low‐cost high‐performance liquid chromatography stationary phase with an excellent chromatographic performance

Abstract

Ground porous silica monolith particles with an average particle size of 2.34 μm and large pores (363 Å) exhibiting excellent chromatographic performance have been synthesized on a relatively large scale by a sophisticated sol-gel procedure. The particle size distribution was rather broad, and the d(0.1)/d(0.9) ratio was 0.14. The resultant silica monolith particles were chemically modified with chlorodimethyloctadecylsilane and end-capped with a mixture of hexamethyldisilazane and chlorotrimethylsilane. Very good separation efficiency (185,000/m) and chromatographic resolution were achieved when the C18 -bound phase was evaluated for a test mixture of five benzene derivatives after packing in a stainless-steel column (1.0 mm × 150 mm). The optimized elution conditions were found to be 70:30 v/v acetonitrile/water with 0.1% trifluoroacetic acid at a flow rate of 25 μL/min. The column was also evaluated for fast analysis at a flow rate of 100 μL/min, and all the five analytes were eluted within 3.5 min with reasonable efficiency (ca. 60,000/m) and resolution. The strategy of using particles with reduced particle size and large pores (363 Å) combined with C18 modification in addition to partial-monolithic architecture has resulted in a useful stationary phase (C18 -bound silica monolith particles) of low production cost showing excellent chromatographic performance.

Styrene‐N‐phenylacrylamide co‐polymer modified silica monolith particles with an optimized mixing ratio of monomers as a new stationary phase for the separation of peptides in high performance liquid chromatography

“…Ligand-modified silica monolith particles have higher separation efficiency (up to 195 000 plates/m) and permeability (2.4 × 10 −14 m 2 for 3.9 µm C18 modified silica monolith particles) than spherical porous silica particles [23]. Their separation efficiency is comparable to that of core-shell particles of similar average particle sizes while the resultant column back pressure is lower (roughly two-thirds) than that of conventional spherical particles [18][19][20][21][22][23]. Such phases reported in the previous studies were C18 modified and polystyrene modified phases.…”

“…The stationary phases based on ground silica monolith particles may be adopted to solve the column packing difficulties. Such stationary phases have been developed in our laboratory [15][16][17][18][19][20][21][22][23]. Their unique character of multiple particle shapes causes a partially monolithic structure in the packed bed enabling fast slurry flux during packing to result in improved packing quality.…”

An optimized mixed‐mode stationary phase based on silica monolith particles for the separation of peptides and proteins in high‐performance liquid chromatography

“…Ground silica monolith particles, a special type of packing material, have higher permeability (2.4 × 10 −14 m 2 for 3.9 µm C18 modified silica monolith particles) and separation efficiency (up to 195 000 plates/m) than spherical porous silica particles . The resultant back pressure of C18 bound silica monolith particles is lower (roughly two thirds) than that of stationary phases based on spherical core‐shell particles while separation efficiency is comparable with that of core‐shell particles of similar average particle sizes . For example, the chromatographic performances of a series of columns packed with various Kinetex C18 core‐shell particles (5, 2.6, 1.7, 1.3 µm) were reported .…”

Cheap C18‐modified Silica Monolith Particles as HPLC Stationary Phase of Good Separation Efficiency

“…In our another previous study, C18‐modified partially sub‐1 µm silica monolith particles were prepared and packed in a column of 15 cm length to show excellent separation efficiency with the number of theoretical plates (N) of about 180,000/m. Nevertheless, the N value per column was only 27,000 since the maximum length of the packed column was only 15 cm due to the reduced particle size.…”