两种β-环糊精单臂键合固定相液相色谱法拆分三唑类手性农药

以有序介孔材料SBA-15为基质, β-环糊精和氨基β-环糊精为配体, 通过环糊精端口的羟基和氨基与3-异氰酸丙基三乙氧基硅烷偶联剂上活泼的异氰酸酯基之间的加成反应, 制备了2种不同单键合臂的β-环糊精修饰SBA-15手性固定相(CDSP和NCDSP), 它们分别含有稳定的氨基甲酸酯基和脲基键合臂. 在反相高效液相色谱模式下, 以灭菌唑、 烯唑醇、 己唑醇和戊唑醇等10种常见的三唑类手性农药为探针, 考察了CDSP和NCDSP的基本手性色谱性能. 研究结果表明, 2种新固定相对三唑类农药对映体均有较好的快速拆分能力, 所需分离时间较短(< 30 min), 其中灭菌唑和烯唑醇的选择性因子(α)分别为1.29和1.28, 分离度分别达到3.84和3.23. 采用甲醇、 乙腈和水组成的简单流动相, 室温下在CDSP和NCDSP上分别拆分了9种和8种三唑类手性农药对映体. 研究发现拥有适当大小和手性碳连接羟基的三唑类农药在上述2种新固定相上有较好的拆分效果, 说明固定相上的环糊精配体对溶质的包结、 氢键和空间位阻等协同作用对空间手性识别有重要贡献. 不同批次CDSP和NCDSP的键合量分别为0.139~0.156和0.120~0.137 μmol/m², 表明2种固定相的制备方法有较好的重现性. 与涂覆型纤维素商品柱相比, 新的脲基环糊精固定相性能更稳定, 反相色谱实用性更强, 且制备方法简便, 成本较低, 在三唑类手性农药对映体残留量检测中具有良好的应用前景.

Enantioseparations of Triazole Chiral Pesticides on Two β-Cyclodextrin-bonded Stationary Phases with Different Linkages by HPLC†

Two kinds of new β-cyclodextrin-bonded chiral stationary phases(CDSP and NCDSP) with carbamate and urea linkages were prepared using ordered mesoporous material SBA-15 as matrix, β-cyclodextrin and 6-amino β-cyclodextrin as ligands via the addition reactions of OH and NH₂ groups of β-cyclodextrin with active 3-isocyanatopropyltriethoxy silane, respectively. The enantioseparation properties of two new stationary phases were evaluated and compared by adopting 10 kinds of common chiral triazole pesticides as probes including triticonazole, diniconazole, hexaconazole, tebuconazole, etc. in reversed-phase mode. The results show that CDSP and NCDSP exhibited excellent and fast chiral separation ability for triazole pesticides within 30 min. Nine and eight kinds of triazole enantiomers were separated on CDSP and NCDSP at room temperature with methanol/H₂O and acetonitrile/H₂O as mobile phase, respectively. The chiral selectivity factor(α) are 1.29 for triticonazole with a resolution of 3.84 for CDSP and 1.28 for diniconazole with a resolutions of 3.23 for NCDSP. It was found that triazole pesticides with appropriate size and —OH groups on CDSP and NCDSP had better separation effect, indicating that the inclusion, hydrogen bonding, steric hindance and other synergic forces between β-cyclodextrin ligand and solutes could contribute enantioseparations. The surface loading of CDSP and NCDSP by different batches were 0.139—0.156 and 0.120—0.137 μmol/m², respectively, indicating that the new preparation methods have good reproducibility. Compared with the commodity coated cellulose column, the new cyclodextrin stationary phases with urea and carbamate linkages were more stable, more practical, easy preparation and low cost. The prepared β-cyclodextrin stationary phases have good prospects in the enantiomeric monitoring of triazole pesticides residues.