title: Tunable thick porous silica coating fabricated by multilayer-by-multilayer bonding of silica nanoparticles for open-tubular capillary chromatographic separation.
abstract: A simple coating procedure employing a multilayer-by-multilayer process to modify the inner surface of bare fused-silica capillaries with silica nanoparticles was established. The silica nanoparticles were adsorbed onto the capillary wall via a strong electrostatic interaction between amino functional groups and silica particles. The thickness of the coating could be tuned from 130 to 600 nm by increasing the coating cycles from one to three. Both the retention factor and the resolution were greatly increased with increasing coating cycles. The loading capacity determined by naphthalene in the column with three coating cycles is 152.1 pmol. The effects of buffer concentration and pH value on the stability of the coating were evaluated. The retention reproducibility of the separation of toluene was 0.8, 1.2, 2.3, and 4.5%, respectively, for run-to-run, day-to-day, column-to-column, and batch-to-batch, respectively. The chromatographic performance of these columns was evaluated by both capillary liquid chromatography and open-tubular capillary electrochromatography (OT-CEC). Separation of aromatic hydrocarbons in the column with three coating cycles provided high theoretical plate numbers (up to 269,280 plates m(-1) for toluene) and short separation time (<15 min) by using OT-CEC mode. The method was also used to separate egg white proteins. Both acidic and basic proteins as well as four glycoisoforms were separated in a single run.
authors.affiliation: Key Laboratory of Functional Molecule Design and Interface Process, School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China. Electronic address: quqishu@qq.com.
authors.forename: Qishu
authors.initials: Q
authors.lastname: Qu
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Shi
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yan
authors.affiliation: UL-CCIC Company Limited, Suzhou 215122, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Tang
mesh_terms: D002021:Buffers; D053801:Capillary Electrochromatography; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D006841:Hydrocarbons, Aromatic / Q000032:analysis / Q000302:isolation & purification; D053758:Nanoparticles / Q000737:chemistry*; D016062:Porosity; D011506:Proteins / Q000737:chemistry; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D002021:Buffers; D006841:Hydrocarbons, Aromatic; D011506:Proteins; D012822:Silicon Dioxide
keywords: Multilayer-by-multilayer; Open-tubular column; Silica nanoparticles; Tunable thickness