Capillary silica is reacted with the monomer through the externally polymerization process so that a capillary silica polymer will be formed. The formed silica polymer will be modified with dimethylamine as an anion exchange group. Modified silica polymers, their morphological form are characterized by SEM and to see the series of functional groups in polymerized silica polymers will be characterized using FTIR. This research begins with the activation of capillary silica to be used, namely capillary silica with an inner diameter of 0.32 mm. After obtaining the optimum conditions of capillary silica to be used, silica will be reacted with several monomers such as glycydil methacrylate (GMA), azobisisobutyronitrile (AIBN) as an initiator, ethylene dimethacrylate (EDMA) as a crosslinker and porogen 1,4 butanadiol, 1-propanol, and water, by comparison of certain compositions to create a capillary silica polymer. Capillary silica polymers that have been externally polymerized will be modified with dimethylamine (DMA) as an anion exchange group and will be applied as a stationary phase for nitrite and nitrate anion analysis.