The pore size distribution of the first and the second generation of silica monolithic stationary phases

•The distribution of the mesopores is narrower for 2G silica monolith than for 1G monolith.•The average mesopore sizes are rather similar in the two generations of silica monoliths.•Macropores in 2G silica monoliths are 40% smaller than in 1G monoliths.

The mesopore structure (pore size and its distribution) for the first and second generations of silica-based monolithic columns was determined by inverse size-exclusion chromatography. The effect of pore size distribution was considered via the molecular theory of size-exclusion chromatography. The molecular theory of chromatography allows taking into account the kinetics of the pore ingress and egress processes, the heterogeneity of the pore sizes and polymer polydispersity. Besides, the mesopore structure, the characteristic domain sizes of the macropores present in the first and second generations of silica-based monolithic columns were also characterized.