Preparation of new hydrophilic monolithic columns and their applications in capillary liquid chromatography and pressurized capillary electrochromatography

Abstract

New hydrophilic monolithic columns were prepared with {[3-(methacryloylamino) propyl] dimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SPP)} as monomer, pentaerythritol triacrylate (PETA) as crosslinking agent, azobisisobutyronitrile (AIBN) as initiator with two different porogens consisting of ethanol/ethylene glycol and methanol/1 ,4-butanediol, separately. In order to obtain monolithic columns with satisfactory efficiency, electroosmotic flow (EOF) velocity and permeability, the contents of the polymerization mixture were investigated and optimized. The performances of the two columns were compared in the permeability and separation performance. It was found that the monolithic column prepared with ethanol/ ethylene glycol had a better column efficiency and selectivity than that with methanol/1,4-butanediol, but was inferior to the latter in permeability. The effect of salt concentration (from 10 to 70 mmol/L ammonium formate) on the retention of nucleosides was investigated. It was observed that the retention factors of these nucleosides increased at first and then decreased. The columns were used in capillary liquid chromatography (cLC) and pressurized capillary electrochromatography (pCEC) for the separation of a test mixture of amines, phenols and nucleosides separately, and satisfactory separations for these samples were achieved. The column used in pCEC system showed better separation and higher speed of the mixture consisted of phenols and nucleosides compared to those used in cLC system.

Advancements in the preparation of high-performance liquid chromatographic organic polymer monoliths for the separation of small-molecule drugs

“…The other type porogen, in which the monomer is insoluble, results in a smaller pore structure. In recent years, binary and ternary porogens have often been used in the preparation of monolithic organic polymer columns [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] ( Table 3 ).…”

“… Type of monoliths Monolithic column Porogen Ref. Poly(styrene- co -divinylbenzene) Water, methanol, ethanol [30] 1-propanol, formamide [31] Toluene, isooctane [32] Toluene, isooctane methacrylic acid(micro-porogen) [32] Polymethacrylate-based monoliths Poly(BMA-EDMA) 1-propanol, 1,4-butanediol, water [33] Poly(SMA-co-2-Me-1,8-ODDMA) Tert.-butanol, 1,4-butanediol [34] Poly(BMA-co-EDMA) 1-propanol, 1,4-butanediol, water [35] Poly(BMA-co-META-co-EDMA) Water, 1,4-butanediol, 1-propanol [36] Poly(1,12-DoDDMA) Methanol, dodecanol [22] Poly (VER-co-EDMA) n -butanol, 1,4-butanediol, water [26] Poly (SPP- PETA) Ethanol, ethylene glycol [37] Poly(HDDA-co-BMA-co-EDMA) Dodecyl alcohol [38] Poly(TAIC -TMPTA) Polyethylene glycol 200, 1,2-propanediol [39] Polymers Glycerol dimethacrylate Polystyrene, chlorobenzene [40] Poly(ethylene glycol methyl ether acrylate-co-polyethylene glycol diacrylate) Ethyl ether, poly(ethyleneoxide)-poly(propylene oxide)-poly(ethylene oxide) [41] Note: butylmethacrylate (BMA), ethylenedimethacrylate (EDMA), stearyl methacrylate (SMA), 2-methyl-1,8-octanediol dimethacrylate (2-Me-1,8-ODDMA), [2-(methacryloyloxy)ethyl]-trimethyl ammonium chloride (META), 1,12-dodecanediol dimethacrylate (1,12-DoDDMA), vinyl ester resin(VER), triallyl isocyanurate (TAIC) -trimethylolpropane triacrylate (TMPTA), {[3-(methacryloylamino) propyl] dimethyl(3-sulf...…”

“…Gao et al [37] used [3-(methacryloylamino) propyl]dimethyl(3-sulfopropyl)ammonium hydroxide inner salt (SPP) as a zwitterionic monomer, PETA as a crosslinking agent, and ethanol-ethylene glycol as a porogen to synthesize a hydrophilic SPP-co-PETA monolith, on which phenolic compounds were successfully separated. Then they compared the hydrophilic properties of monolithic columns prepared using various porogens when nuclear glycosides and phenolic compounds were used as model compounds.…”

“…In 2012, Gao et al [37] used SPP as a zwitterionic monomer, PETA as a crosslinking agent, AMPS as an electroosmotic flow donator, AIBN as an initiator, and ethanol-ethylene glycol as a porogen to synthesize a hydrophilic (SPP-co-PETA) monolith, on which phenolic compounds were successfully separated. The use of ethanol-ethylene glycol as the porogen provided the prepared monolithic column with high column efficiency and better separation performance.…”