Photopolymerized sol-gel frits for packed columns in capillary electrochromatography

Porous sol-gel frits are fabricated in a capillary column by filling it wit h a solution of 3-(trimethoxysilyl)propyl methacrylate, hydrochloric acid, water, toluene (porogen), and a photoinitiator (Irgacure 1800) and exposing it to UV light at 365 nm for 5 min. The separation column (30 cmx75 mum I. D.) contains between the inlet and outlet frits a 15-cm packed segment fill ed with 5-mum silica particles modified with the chiral compound (S)-N-3,5- dinitrobenzoyl-1-naphthylglycine. A detection window (I mm long) is placed immediately after the outlet frit. To demonstrate the performance of this c hiral separation column, mixtures of 16 different amino acids (three of whi ch are not naturally occurring) derivatized with the fluorogenic reagent 4- fluoro-7-nitro-2,1,3-benzoxadiazole were separated by capillary chromatogra phy. The enantiomeric separation of the column results in a resolution rang ing from 1.21 to 8.29, and a plate height ranging from 8.7 to 39 mum. (C) 2 001 Elsevier Science B.V. All rights reserved.