3,5-二硝基苯甲酰基高效液相色谱键合硅胶固定相的制备与评价

以N-(β-氨乙基)-γ-氨丙基甲基二甲氧基硅烷为偶联剂,建立了一种制备3,5-二硝基苯甲酰基键合硅胶固定相(DNB)的新方法。采用元素分析、红外光谱和热分析表征了该固定相的结构。根据元素分析碳含量结果,计算出DNB表面配体浓度为2.08 μmol/m2。以芳烃(PAHs)、酚类、芳胺类、硝基苯酚异构体和磺胺类化合物作溶质探针,较系统地研究了该固定相的色谱性能。研究表明,所制备的固定相除了具有弱的疏水性外,还能与溶质发生电荷转移、静电、氢键和偶极-偶极等作用,从而提高对溶质的分离选择性。同时,由于间隔基对硅醇羟基的屏蔽作用,适用于含氮的碱性化合物的分离。

Preparation and Evaluation of 3,5-Dinitrobenzoyl-Bonded Silica Gel Stationary Phase for High Performance Liquid Chromatography

A new preparation method of 3,5-dinitrobenzoyl-bonded silica gel stationary phase (DNB) for high performance liquid chromatography has been developed by using N-(beta-aminoethyl)-gamma-aminopropyl-methyldimethoxy silane as coupling reagent. Its structure was characterized by elemental analysis, diffuse reflectance Fourier transform infrared spectroscopy and thermal analysis. The surface concentration of 3,5-dinitrobenzoyl ligand was 2.08 micromol/m2 according to the carbon content from elemental analysis. The chromatographic performance of the new packing was evaluated by using different solute probes, such as polycyclic aromatic hydrocarbons (PAHs), phenols, naphthalene derivatives, nitrophenol positional isomers and sulfonamides. The results show that comparing with ODS, DNB has weaker hydrophobicity and more versatile chromatographic properties. The charge-transfer between the dinitrobenzoyl ligand and the analytes plays a significant role in the separation of phenols and naphthalene derivatives. In addition, static electric, hydrogen-bonding and dipole-dipole interactions are responsible for the above separations and improve the selectivity of DNB for solutes. An advantage of DNB is that it is suitable for the separation of the basic compounds containing nitrogen atoms without capped process because the spacer containing nitrogen atoms can shield the residual silanols on DNB.